WO2015017406A1 - Structure de filtre rf accordable présentant des résonateurs couplés - Google Patents

Structure de filtre rf accordable présentant des résonateurs couplés Download PDF

Info

Publication number
WO2015017406A1
WO2015017406A1 PCT/US2014/048608 US2014048608W WO2015017406A1 WO 2015017406 A1 WO2015017406 A1 WO 2015017406A1 US 2014048608 W US2014048608 W US 2014048608W WO 2015017406 A1 WO2015017406 A1 WO 2015017406A1
Authority
WO
WIPO (PCT)
Prior art keywords
filter
tunable
resonator
filter path
cross
Prior art date
Application number
PCT/US2014/048608
Other languages
English (en)
Inventor
Dirk Robert Walter LEIPOLD
George Maxim
Baker Scott
Original Assignee
Rf Micro Devices, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US14/298,829 external-priority patent/US9455680B2/en
Application filed by Rf Micro Devices, Inc. filed Critical Rf Micro Devices, Inc.
Publication of WO2015017406A1 publication Critical patent/WO2015017406A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/09—Filters comprising mutual inductance
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/207—Hollow waveguide filters
    • H01P1/208—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1708—Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/004—Capacitive coupling circuits not otherwise provided for

Definitions

  • Embodiments of the present disclosure relate to radio frequency (RF) communications systems, which may include RF front-end circuitry, RF transceiver circuitry, RF amplifiers, direct current (DC)-DC converters, RF filters, RF antennas, RF switches, RF combiners, RF splitters, the like, or any combination thereof.
  • RF radio frequency
  • wireless communications systems become increasingly sophisticated.
  • wireless communications protocols continue to expand and change to take advantage of the technological evolution.
  • many wireless communications devices must be capable of supporting any number of wireless communications protocols, each of which may have certain performance requirements, such as specific out-of-band emissions requirements, linearity requirements, or the like.
  • portable wireless communications devices are typically battery powered and need to be relatively small, and have low cost.
  • RF circuitry in such a device needs to be as simple, small, flexible, and efficient as is practical.
  • RF circuitry in a communications device that is low cost, small, simple, flexible, and efficient.
  • the RF filter structures may have multiple filter paths, which are provided by weakly coupled resonators.
  • the filter paths may be interconnected so that additional filter paths may be realized between input and output terminals of the RF filter structures.
  • the weakly coupled resonators from the filter paths may be arranged in a matrix.
  • an RF filter structure includes a first filter path and a second filter path.
  • the first filter path includes (at least) a first pair of weakly coupled resonators, while the second filter path includes (at least) a second pair of weakly coupled resonators.
  • a cross-coupling capacitive structure is electrically connected between the first filter path and the second filter path.
  • an additional filter path may be realized through the interconnection provided by the cross-coupling capacitive structure.
  • Figure 2 shows the traditional communications circuitry according to the prior art.
  • Figure 3 shows the traditional communications circuitry according to the prior art.
  • Figure 4 shows RF communications circuitry according to one embodiment of the RF communications circuitry.
  • Figure 5 is a graph illustrating filtering characteristics of a first tunable RF filter path and a second tunable RF filter path illustrated in Figure 4 according to one embodiment of the first tunable RF filter path and the second tunable RF filter path.
  • Figures 6A and 6B are graphs illustrating filtering characteristics of the first tunable RF filter path and the second tunable RF filter path, respectively, illustrated in Figure 4 according to an alternate embodiment of the first tunable RF filter path and the second tunable RF filter path, respectively.
  • Figure 7 shows the RF communications circuitry according to one embodiment of the RF communications circuitry.
  • Figure 8 shows the RF communications circuitry according to an alternate embodiment of the RF communications circuitry.
  • Figures 9A and 9B are graphs illustrating filtering characteristics of the first tunable RF filter path and the second tunable RF filter path, respectively, illustrated in Figure 8 according to an additional embodiment of the first tunable
  • Figures 10A and 10B are graphs illustrating filtering characteristics of a first traditional RF duplexer and a second traditional RF duplexer, respectively, illustrated in Figure 3 according to the prior art.
  • Figure 1 1 shows the RF communications circuitry according to one embodiment of the RF communications circuitry.
  • Figure 12 shows the RF communications circuitry according to an alternate embodiment of the RF communications circuitry.
  • Figure 13 shows the RF communications circuitry according to an additional embodiment of the RF communications circuitry.
  • Figure 14 shows the RF communications circuitry according to another embodiment of the RF communications circuitry.
  • Figure 15 shows the RF communications circuitry according to a further embodiment of the RF communications circuitry.
  • Figure 16 shows the RF communications circuitry according to one embodiment of the RF communications circuitry.
  • Figure 17 shows the RF communications circuitry according to an alternate embodiment of the RF communications circuitry.
  • Figure 18 shows the RF communications circuitry according to an additional embodiment of the RF communications circuitry.
  • Figure 19 shows the RF communications circuitry according to another embodiment of the RF communications circuitry.
  • Figure 20 shows the RF communications circuitry according to a further embodiment of the RF communications circuitry.
  • Figure 21 illustrates one embodiment of a tunable radio frequency (RF) filter structure that defines multiple tunable RF filtering paths that are
  • Figure 22 illustrates one embodiment of a tunable RF filter path shown in Figure 21 having cross-coupling capacitors arranged in a V-bridge structure.
  • Figure 23 illustrates another embodiment of the tunable RF filter path shown in Figure 21 having cross-coupling capacitors arranged in an X-bridge structure.
  • Figure 24 illustrates another embodiment of the tunable RF filter path shown in Figure 21 having a cross-coupling capacitor arranged in a single positive bridge structure.
  • Figure 25 illustrates another embodiment of the tunable RF filter path shown in Figure 21 having cross-coupling capacitors arranged in an H-bridge structure.
  • Figure 26 illustrates another embodiment of the tunable RF filter path shown in Figure 21 having cross-coupling capacitors arranged in a double H- bridge structure.
  • Figure 27 illustrates another embodiment of the tunable RF filter path shown in Figure 21 having four weakly coupled resonators with magnetic and electric couplings between them.
  • Figures 28A-28D disclose different embodiments of a tunable RF filter structure, each with a different number of input terminals and output terminals.
  • Figure 29 illustrates one embodiment of a tunable radio frequency (RF) filter structure having four resonators and cross-coupling capacitive structures electrically connected between the four resonators so as to form a 2X2 matrix with the four resonators.
  • RF radio frequency
  • Figure 30 illustrates another embodiment of a tunable RF filter structure having M number of rows and N number of columns of resonators that are electrically connected by cross-coupling capacitive structures so that the tunable RF filter structure is arranged so as to form an MXN two-dimensional matrix of the resonators.
  • Figure 31 illustrates the tunable RF filter structure shown in Figure 30 electrically connected to various RF antennas.
  • Figure 32 illustrates the tunable RF filter structure shown in Figure 30 with two tunable RF filter paths highlighted for performing Multiple Input Multiple
  • MIMO Single Input Multiple Output
  • SIMO Multiple Input Single Output
  • MISO MISO
  • SISO Single Input Single Output
  • Figure 33 illustrates another embodiment of a tunable RF filter structure with amplifier stages electrically connected within and between tunable
  • Figure 34 illustrates an embodiment of a tunable RF filter structure integrated into an integrated circuit (IC) package with multiple and separate semiconductor dies.
  • Figure 35 illustrates an embodiment of the same tunable RF filter structure shown in Figure 34, but now integrated into an IC package with a single semiconductor die.
  • Figure 36 illustrates one embodiment of a tunable RF filter structure having resonators and cross-coupling capacitive structures electrically connected between the resonators so as to form a three-dimensional matrix of the resonators.
  • RF communications circuitry which includes a first RF filter structure, is disclosed according to a first embodiment of the present disclosure.
  • the first RF filter structure includes a first tunable RF filter path and a second tunable RF filter path.
  • the first tunable RF filter path includes a pair of weakly coupled resonators. Additionally, a first filter parameter of the first tunable RF filter path is tuned based on a first filter control signal. A first filter parameter of the second tunable RF filter path is tuned based on a second filter control signal.
  • the first tunable RF filter path is directly coupled between a first common connection node and a first connection node.
  • the second tunable RF filter path is directly coupled between a second connection node and the first common connection node.
  • the first tunable RF filter path and the second tunable RF filter path do not significantly load one another at frequencies of interest.
  • front-end RF switching elements may be avoided, thereby reducing cost, size, and non-linearity; and increasing efficiency and flexibility of the RF communications system.
  • the first common connection node is coupled to an antenna.
  • TDD time division duplex
  • CA carrier-aggregation
  • FIG. 1 shows traditional communications circuitry 10 according to the prior art.
  • the traditional communications circuitry 10 illustrated in Figure 1 is a time-division duplex (TDD) system, which is capable of transmitting and receiving RF signals, but not simultaneously. Such a system may also be called a half- duplex system.
  • the traditional communications circuitry 10 may be used as a simplex system, which is a system that only transmits RF signals or only receives RF signals.
  • Traditional communications systems often use fixed frequency filters. As a result, to cover multiple communications bands, switching elements are needed to select between different signal paths.
  • the traditional communications circuitry 10 includes traditional RF system control circuitry 12, traditional RF front-end circuitry 14, and a first RF antenna 16.
  • the traditional RF front-end circuitry 14 includes traditional RF front- end control circuitry 18, first traditional antenna matching circuitry 20, first traditional RF receive circuitry 22, first traditional RF transmit circuitry 24, a first traditional RF switch 26, and a second traditional RF switch 28.
  • the first traditional RF switch 26 is coupled between the first traditional antenna matching circuitry 20 and the first traditional RF receive circuitry 22.
  • the second traditional RF switch 28 is coupled between the first traditional antenna matching circuitry 20 and the first traditional RF transmit circuitry 24.
  • the first RF antenna 16 is coupled to the first traditional antenna matching circuitry 20.
  • the first traditional antenna matching circuitry 20 provides at least partial impedance matching between the first RF antenna 16 and either the first traditional RF receive circuitry 22 or the first traditional RF transmit circuitry 24.
  • the traditional RF system control circuitry 12 provides the necessary control functions needed to facilitate RF communications between the traditional communications circuitry 10 and other RF devices.
  • the traditional RF system control circuitry 12 processes baseband signals needed for the RF
  • the traditional RF system control circuitry 12 provides a first traditional upstream transmit signal TUT1 to the first traditional RF transmit circuitry 24.
  • the first traditional upstream transmit signal TUT1 may be a baseband transmit signal, an intermediate frequency (IF) transmit signal, or an RF transmit signal.
  • the traditional RF system control circuitry 12 receives a first traditional downstream receive signal TDR1 from the first traditional RF receive circuitry 22.
  • the first traditional downstream receive signal TDR1 may be a baseband receive signal, an IF receive signal, or an RF receive signal.
  • the first traditional RF transmit circuitry 24 may include up-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the first traditional RF receive circuitry 22 may include down-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the traditional RF system control circuitry 12 provides a traditional front-end control signal TFEC to the traditional RF front-end control circuitry 18.
  • the traditional RF front-end control circuitry 18 provides a first traditional switch control signal TCS1 and a second traditional switch control signal TCS2 to the first traditional RF switch 26 and the second traditional RF switch 28,
  • the traditional RF system control circuitry 12 controls the first traditional RF switch 26 and the second traditional RF switch 28 via the traditional front-end control signal TFEC.
  • the first traditional RF switch 26 is in one of an ON state and an OFF state based on the first traditional switch control signal TCS1 .
  • the second traditional RF switch 28 is in one of an ON state and an OFF state based on the second traditional switch control signal TCS2.
  • Half-duplex operation of the traditional communications circuitry 10 is accomplished using the first traditional RF switch 26 and the second traditional RF switch 28.
  • the traditional communications circuitry 10 is transmitting RF signals via the first RF antenna 16
  • the first traditional RF switch 26 is in the OFF state and the second traditional RF switch 28 is in the ON state.
  • the first traditional antenna matching circuitry 20 is electrically isolated from the first traditional RF receive circuitry 22 and the first traditional antenna matching circuitry 20 is electrically coupled to the first traditional RF transmit circuitry 24.
  • the traditional RF system control circuitry 12 provides the first traditional upstream transmit signal TUT1 to the first traditional RF transmit circuitry 24, which provides a traditional transmit signal TTX to the first RF antenna 16 via the second traditional RF switch 28 and the first traditional antenna matching circuitry 20 based on the first traditional upstream transmit signal TUT1 .
  • the first traditional RF switch 26 When the traditional communications circuitry 10 is receiving RF signals via the first RF antenna 16, the first traditional RF switch 26 is in the ON state and the second traditional RF switch 28 is in the OFF state. As such, the first traditional antenna matching circuitry 20 is isolated from the first traditional RF transmit circuitry 24 and the first traditional antenna matching circuitry 20 is electrically coupled to the first traditional RF receive circuitry 22. In this regard, the first traditional antenna matching circuitry 20 receives the RF signals from the first RF antenna 16 and forwards the RF signals via the first traditional RF switch 26 to the first traditional RF receive circuitry 22.
  • the first traditional RF switch 26 provides a traditional receive signal TRX to the first traditional RF receive circuitry 22, which provides a first traditional downstream receive signal TDR1 to the traditional RF system control circuitry 12 based on the traditional receive signal TRX.
  • the traditional communications circuitry 10 illustrated in Figure 1 is a half-duplex system, during operation, the first traditional RF switch 26 and the second traditional RF switch 28 are not simultaneously in the ON state.
  • the first traditional RF receive circuitry 22 and the first traditional RF transmit circuitry 24 are isolated from one another. As such, the first traditional RF receive circuitry 22 and the first traditional RF transmit circuitry 24 are prevented from interfering with one another.
  • FIG. 2 shows the traditional communications circuitry 10 according to the prior art.
  • the traditional communications circuitry 10 illustrated in Figure 2 is similar to the traditional communications circuitry 10 illustrated in Figure 1 , except in the traditional communications circuitry 10 illustrated in Figure 2, the traditional RF front-end control circuitry 18, the first traditional RF switch 26, and the second traditional RF switch 28 are omitted, and the traditional RF front-end circuitry 14 further includes a first traditional RF duplexer 30.
  • the first traditional RF duplexer 30 is coupled between the first traditional antenna matching circuitry 20 and the first traditional RF receive circuitry 22, and is further coupled between the first traditional antenna matching circuitry 20 and the first traditional RF transmit circuitry 24.
  • the traditional communications circuitry 10 illustrated in Figure 2 may be used as a TDD system or a simplex system. However, the traditional communications circuitry 10 illustrated in Figure 2 may also be used as a frequency-division duplex (FDD) system, which is capable of transmitting and receiving RF signals simultaneously. Such a system may also be called a full- duplex system.
  • FDD frequency-division duplex
  • the traditional RF system control circuitry 12 provides the first traditional upstream transmit signal TUT1 to the first traditional RF transmit circuitry 24, which provides the traditional transmit signal TTX to the first RF antenna 16 via first traditional RF duplexer 30 based on the first traditional upstream transmit signal TUT1 .
  • the first traditional antenna matching circuitry 20 receives the RF signals from the first RF antenna 16 and forwards the RF signals via the first traditional RF duplexer 30 to the first traditional RF receive circuitry 22.
  • the first traditional RF duplexer 30 provides the traditional receive signal TRX to the first traditional RF receive circuitry 22, which provides the first traditional downstream receive signal TDR1 to the traditional RF system control circuitry 12 based on the traditional receive signal TRX.
  • the first traditional RF duplexer 30 provides filtering, such that the first traditional RF receive circuitry 22 and the first traditional RF transmit circuitry 24 are substantially isolated from one another. As such, the first traditional RF receive circuitry 22 and the first traditional RF transmit circuitry 24 are prevented from interfering with one another.
  • Traditional FDD systems using duplexers with high rejection ratios have a fixed frequency transfer. Covering multiple communications bands requires multiple duplexers and switches to route RF signals through appropriate signal paths.
  • FIG 3 shows the traditional communications circuitry 10 according to the prior art.
  • the traditional communications circuitry 10 illustrated in Figure 3 is a carrier aggregation (CA) based system, which is capable of transmitting or receiving multiple simultaneous transmit signals or multiple simultaneous receive signals, respectively, or both.
  • Each of the simultaneous transmit signals is in a frequency band that is different from each frequency band of a balance of the simultaneous transmit signals.
  • each of the simultaneous receive signals is in a frequency band that is different from each frequency band of a balance of the simultaneous receive signals.
  • the traditional communications circuitry 10 may operate as a simplex system, a half-duplex system, or a full- duplex system.
  • the traditional communications circuitry 10 includes the traditional RF system control circuitry 12, the traditional RF front-end circuitry 14, the first RF antenna 16, and a second RF antenna 32.
  • the traditional RF front-end circuitry 14 includes the first traditional antenna matching circuitry 20, the first traditional RF receive circuitry 22, the first traditional RF transmit circuitry 24, the first traditional RF duplexer 30, first traditional antenna switching circuitry 34, a second traditional RF duplexer 36, a third traditional RF duplexer 38, second traditional antenna matching circuitry 40, second traditional antenna switching circuitry 42, a fourth traditional RF duplexer 44, a fifth traditional RF duplexer 46, a sixth traditional RF duplexer 48, second traditional RF receive circuitry 50, and second traditional RF transmit circuitry 52.
  • Traditional CA systems use fixed frequency filters and diplexers, triplexers, or both to combine signal paths, which increases complexity. Alternatively, additional switch paths may be used, but may degrade performance.
  • the first traditional antenna matching circuitry 20 is coupled between the first RF antenna 16 and the first traditional antenna switching circuitry 34.
  • the second traditional antenna matching circuitry 40 is coupled between the second RF antenna 32 and the second traditional antenna switching circuitry 42.
  • the first traditional RF duplexer 30 is coupled between the first traditional antenna switching circuitry 34 and the first traditional RF receive circuitry 22, and is further coupled between the first traditional antenna switching circuitry 34 and the first traditional RF transmit circuitry 24.
  • the second traditional RF duplexer 36 is coupled between the first traditional antenna switching circuitry 34 and the first traditional RF receive circuitry 22, and is further coupled between the first traditional antenna switching circuitry 34 and the first traditional RF transmit circuitry 24.
  • the third traditional RF duplexer 38 is coupled between the first traditional antenna switching circuitry 34 and the first traditional RF receive circuitry 22, and is further coupled between the first traditional antenna switching circuitry 34 and the first traditional RF transmit circuitry 24.
  • the fourth traditional RF duplexer 44 is coupled between the second traditional antenna switching circuitry 42 and the second traditional RF receive circuitry 50, and is further coupled between the second traditional antenna switching circuitry 42 and the second traditional RF transmit circuitry 52.
  • the fifth traditional RF duplexer 46 is coupled between the second traditional antenna switching circuitry 42 and the second traditional RF receive circuitry 50, and is further coupled between the second traditional antenna switching circuitry 42 and the second traditional RF transmit circuitry 52.
  • the sixth traditional RF duplexer 48 is coupled between the second traditional antenna switching circuitry 42 and the second traditional RF receive circuitry 50, and is further coupled between the second traditional antenna switching circuitry 42 and the second traditional RF transmit circuitry 52.
  • the first traditional RF duplexer 30 is associated with a first
  • the second traditional RF duplexer 36 is associated with a second aggregated receive band, a second aggregated transmit band, or both.
  • the third traditional RF duplexer 38 is associated with a third aggregated receive band, a third aggregated transmit band, or both.
  • the fourth traditional RF duplexer 44 is associated with a fourth aggregated receive band, a fourth aggregated transmit band, or both.
  • the fifth traditional RF duplexer 46 is associated with a fifth aggregated receive band, a fifth aggregated transmit band, or both.
  • the sixth traditional RF duplexer 48 is associated with a sixth aggregated receive band, a sixth aggregated transmit band, or both.
  • the first traditional antenna switching circuitry 34 couples a selected one of the first traditional RF duplexer 30, the second traditional RF duplexer 36, and the third traditional RF duplexer 38 to the first traditional antenna matching circuitry 20. Therefore, the first RF antenna 16 is associated with a selected one of the first aggregated receive band, the second aggregated receive band, and the third aggregated receive band; with a selected one of the first aggregated transmit band, the second aggregated transmit band, and the third aggregated transmit band; or both.
  • the second traditional antenna switching circuitry 42 couples a selected one of the fourth traditional RF duplexer 44, the fifth traditional RF duplexer 46, and the sixth traditional RF duplexer 48 to the second traditional antenna matching circuitry 40. Therefore, the second RF antenna 32 is associated with a selected one of the fourth aggregated receive band, the fifth aggregated receive band, and the sixth aggregated receive band; with a selected one of the fourth aggregated transmit band, the fifth aggregated transmit band, and the sixth aggregated transmit band; or both.
  • the traditional RF system control circuitry 12 provides the first traditional upstream transmit signal TUT1 to the first traditional RF transmit circuitry 24, which forwards the first traditional upstream transmit signal TUT1 to the first RF antenna 16 for transmission via the selected one of the first traditional RF duplexer 30, the second traditional RF duplexer 36, and the third traditional RF duplexer 38; via the first traditional antenna switching circuitry 34; and via the first traditional antenna matching circuitry 20.
  • the traditional RF system control circuitry 12 provides a second traditional upstream transmit signal TUT2 to the second traditional RF transmit circuitry 52, which forwards the second traditional upstream transmit signal TUT2 to the second RF antenna 32 for transmission via the selected one of the fourth traditional RF duplexer 44, the fifth traditional RF duplexer 46, and the sixth traditional RF duplexer 48; via the second traditional antenna switching circuitry 42; and via the second traditional antenna matching circuitry 40.
  • the first RF antenna 16 forwards a received RF signal to the first traditional RF receive circuitry 22 via the first traditional antenna matching circuitry 20, the first traditional antenna switching circuitry 34, and the selected one of the first traditional RF duplexer 30, the second traditional RF duplexer 36, and the third traditional RF duplexer 38.
  • the first traditional RF receive circuitry 22 provides the first traditional downstream receive signal TDR1 to the traditional RF system control circuitry 12 based on the received RF signal.
  • the second RF antenna 32 forwards a received RF signal to the second traditional RF receive circuitry 50 via the second traditional antenna matching circuitry 40, the second traditional antenna switching circuitry 42, and the selected one of the fourth traditional RF duplexer 44, the fifth traditional RF duplexer 46, and the sixth traditional RF duplexer 48.
  • the second traditional RF receive circuitry 50 provides a second traditional downstream receive signal TDR2 to the traditional RF system control circuitry 12 based on the received RF signal.
  • the first traditional antenna switching circuitry 34 isolates each of the first traditional RF duplexer 30, the second traditional RF duplexer 36, and the third traditional RF duplexer 38 from one another; and prevents each of the first traditional RF duplexer 30, the second traditional RF duplexer 36, and the third traditional RF duplexer 38 from interfering with one another.
  • the second traditional antenna matching circuitry 40 isolates each of the fourth traditional RF duplexer 44, the fifth traditional RF duplexer 46, and the sixth traditional RF duplexer 48 from one another; and prevents each of the fourth traditional RF duplexer 44, the fifth traditional RF duplexer 46, and the sixth traditional RF duplexer 48 from interfering with one another.
  • FIG. 4 shows RF communications circuitry 54 according to one embodiment of the RF communications circuitry 54.
  • the RF communications circuitry 54 includes RF system control circuitry 56, RF front-end circuitry 58, and the first RF antenna 16.
  • the RF front-end circuitry 58 includes a first RF filter structure 60, RF receive circuitry 62, and RF transmit circuitry 64.
  • the first RF filter structure 60 includes a first tunable RF filter path 66 and a second tunable RF filter path 68. Additionally, the first RF filter structure 60 has a first connection node 70, a second connection node 72, and a first common connection node 74.
  • the RF system control circuitry 56 is an RF transceiver.
  • the first tunable RF filter path 66 includes a pair of weakly coupled resonators R(1 ,1 ), R(1 ,2) ( Figure 22).
  • the RF filter structure 60 includes the pair of weakly coupled resonators R(1 ,1 ), R(1 ,2) ( Figure 21 ).
  • any or all of the first connection node 70, the second connection node 72, and the first common connection node 74 are external to the first RF filter structure 60.
  • the first tunable RF filter path 66 includes a first pair (not shown) of weakly coupled resonators.
  • the second tunable RF filter path 68 includes a second pair (not shown) of weakly coupled resonators.
  • the first tunable RF filter path 66 is directly coupled between the first common connection node 74 and the first connection node 70
  • the second tunable RF filter path 68 is directly coupled between the second connection node 72 and the first common connection node 74
  • the first RF antenna 16 is directly coupled to the first common connection node 74.
  • the first RF antenna 16 is omitted.
  • the RF receive circuitry 62 is coupled between the first connection node 70 and the RF system control circuitry 56
  • the RF transmit circuitry 64 is coupled between the second connection node 72 and the RF system control circuitry 56.
  • the first tunable RF filter path 66 is a first RF receive filter, such that the first RF antenna 16 forwards a received RF signal via the first common connection node 74 to provide a first upstream RF receive signal RU1 to the first tunable RF filter path 66, which receives and filters the first upstream RF receive signal RU1 to provide a first filtered RF receive signal RF1 to the RF receive circuitry 62.
  • the RF receive circuitry 62 may include down-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the RF receive circuitry 62 processes the first filtered RF receive signal RF1 to provide a first receive signal RX1 to the RF system control circuitry 56.
  • the second tunable RF filter path 68 is a first RF transmit filter, such that the RF system control circuitry 56 provides a first transmit signal TX1 to the RF transmit circuitry 64, which processes the first transmit signal TX1 to provide a first upstream RF transmit signal TU1 to the second tunable RF filter path 68.
  • the RF transmit circuitry 64 may include up-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the second tunable RF filter path 68 receives and filters the first upstream RF transmit signal TU1 to provide a first filtered RF transmit signal TF1 , which is transmitted via the first common connection node 74 by the first RF antenna 16.
  • the RF system control circuitry 56 provides a first filter control signal FCS1 to the first tunable RF filter path 66 and provides a second filter control signal FCS2 to the second tunable RF filter path 68.
  • the RF system control circuitry 56 tunes a first filter parameter of the first tunable RF filter path 66 using the first filter control signal FCS1 . Additionally, the RF system control circuitry 56 tunes a first filter parameter of the second tunable RF filter path 68 using the second filter control signal FCS2.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 do not significantly load one another at frequencies of interest. As such, by directly coupling the first tunable RF filter path 66 and the second tunable RF filter path 68 to the first common connection node 74; front-end RF switching elements may be avoided, thereby reducing cost, size, and non-linearity; and increasing efficiency and flexibility of the RF communications circuitry 54. Since tunable RF filters can support multiple communications bands using a single signal path, they can simplify front-end architectures by eliminating switching and duplexing components.
  • the RF communications circuitry 54 is used as an FDD communications system, such that the first upstream RF receive signal RU1 and the first filtered RF transmit signal TF1 are full-duplex signals.
  • the RF communications circuitry 54 is used as a TDD communications system, such that the first upstream RF receive signal RU1 and the first filtered RF transmit signal TF1 are half-duplex signals.
  • the RF communications circuitry 54 is used as a simplex communications system, such that the first upstream RF receive signal RU1 is a simplex signal and the first filtered RF transmit signal TF1 is not present. In other embodiments of the RF
  • the RF communications circuitry 54 is used as a simplex communications system, such that the first upstream RF receive signal RU1 is not present and the first filtered RF transmit signal TF1 is a simplex signal.
  • Figure 5 is a graph illustrating filtering characteristics of the first tunable RF filter path 66 and the second tunable RF filter path 68 illustrated in Figure 4 according to one embodiment of the first tunable RF filter path 66 and the second tunable RF filter path 68.
  • the first tunable RF filter path 66 is a first RF bandpass filter, which functions as the first RF receive filter
  • the second tunable RF filter path 68 is a second RF bandpass filter, which functions as the first RF transmit filter.
  • a bandwidth 76 of the first RF bandpass filter, a center frequency 78 of the first RF bandpass filter, a bandwidth 80 of the second RF bandpass filter, a center frequency 82 of the second RF bandpass filter, a frequency 84 of the first upstream RF receive signal RU1 ( Figure 4), and a frequency 86 of the first filtered RF transmit signal TF1 ( Figure 4) are shown. Operation of the first RF bandpass filter and the second RF bandpass filter is such that the first RF bandpass filter and the second RF bandpass filter do not significantly interfere with one another. In this regard, the bandwidth 76 of the first RF bandpass filter does not overlap the bandwidth 80 of the second RF bandpass filter.
  • the first RF receive filter and the first RF transmit filter in combination function as an RF duplexer.
  • a duplex frequency 88 of the RF duplexer is about equal to a difference between the frequency 84 of the first upstream RF receive signal RU1 ( Figure 4) and the frequency 86 of the first filtered RF transmit signal TF1 ( Figure 4).
  • the first filter parameter of the first tunable RF filter path 66 is tunable based on the first filter control signal FCS1 .
  • both the first filter parameter of the first tunable RF filter path 66 and a second filter parameter of the first tunable RF filter path 66 are tunable based on the first filter control signal FCS1 .
  • the first filter parameter of the second tunable RF filter path 68 is tunable based on the second filter control signal FCS2.
  • both the first filter parameter of the second tunable RF filter path 68 and a second filter parameter of the second tunable RF filter path 68 are tunable based on the second filter control signal FCS2.
  • the first filter parameter of the first tunable RF filter path 66 is the center frequency 78 of the first RF bandpass filter.
  • the second filter parameter of the first tunable RF filter path 66 is the bandwidth 76 of the first RF bandpass filter.
  • the first filter parameter of the second tunable RF filter path 68 is the center frequency 82 of the second RF bandpass filter.
  • the second filter parameter of the second tunable RF filter path 68 is the bandwidth 80 of the second RF bandpass filter.
  • Figures 6A and 6B are graphs illustrating filtering characteristics of the first tunable RF filter path 66 and the second tunable RF filter path 68,
  • the first tunable RF filter path 66 is an RF lowpass filter and the second tunable RF filter path 68 is an RF highpass filter.
  • Figure 6A shows a frequency response curve 90 of the RF lowpass filter and Figure 6B shows a frequency response curve 92 of the RF highpass filter.
  • Figure 6A shows a break frequency 94 of the RF lowpass filter and Figure 6B shows a break frequency 96 of the RF highpass filter.
  • Both Figures 6A and 6B show the frequency 84 of the first upstream RF receive signal RU1 ( Figure 4), the frequency 86 of the first filtered RF transmit signal TF1 ( Figure 4), and the duplex frequency 88 of the RF duplexer for clarification.
  • the RF lowpass filter and the RF highpass filter in combination function as an RF diplexer.
  • the first filter parameter of the first tunable RF filter path 66 is the break frequency 94 of the RF lowpass filter. In one embodiment of the RF lowpass filter, the RF lowpass filter has bandpass filter characteristics.
  • the first filter parameter of the second tunable RF filter path 68 is the break frequency 96 of the RF highpass filter. In one embodiment of the RF highpass filter, the RF highpass filter has bandpass filter characteristics. In one embodiment of the RF diplexer, the break frequency 96 of the RF highpass filter is about equal to the break frequency 94 of the RF lowpass filter.
  • Figure 7 shows the RF communications circuitry 54 according to one embodiment of the RF communications circuitry 54.
  • the RF communications circuitry 54 illustrated in Figure 7 is similar to the RF communications circuitry 54 illustrated in Figure 4, except in the RF front-end circuitry 58 illustrated in Figure 7, the RF transmit circuitry 64 ( Figure 4) is omitted and the RF front-end circuitry 58 further includes RF front-end control circuitry 98.
  • the RF system control circuitry 56 provides a front-end control signal FEC to the RF front-end control circuitry 98.
  • the RF front-end control circuitry 98 provides the first filter control signal FCS1 and the second filter control signal FCS2 based on the front-end control signal FEC.
  • the RF system control circuitry 56 provides the first filter control signal FCS1 and the second filter control signal FCS2 directly.
  • the RF communications circuitry 54 includes control circuitry, which may be either the RF system control circuitry 56 or the RF front-end control circuitry 98, that provides the first filter control signal FCS1 and the second filter control signal FCS2.
  • the control circuitry tunes a first filter parameter of the first tunable RF filter path 66 using the first filter control signal FCS1 . Additionally, the control circuitry tunes a first filter parameter of the second tunable RF filter path 68 using the second filter control signal FCS2. In an additional embodiment of the RF communications circuitry 54, the control circuitry further tunes a second filter parameter of the first tunable RF filter path 66 using the first filter control signal FCS1 ; and the control circuitry further tunes a second filter parameter of the second tunable RF filter path 68 using the second filter control signal FCS2.
  • any or all of the first connection node 70, the second connection node 72, and the first common connection node 74 are external to the first RF filter structure 60.
  • the first tunable RF filter path 66 includes a first pair (not shown) of weakly coupled resonators.
  • the second tunable RF filter path 68 includes a second pair (not shown) of weakly coupled resonators.
  • the first tunable RF filter path 66 is directly coupled between the first common connection node 74 and the first connection node 70
  • the second tunable RF filter path 68 is directly coupled between the second connection node 72 and the first common connection node 74
  • the first RF antenna 16 is directly coupled to the first common connection node 74.
  • the first RF antenna 16 is omitted.
  • the RF receive circuitry 62 is coupled between the first connection node 70 and the RF system control circuitry 56, and the RF receive circuitry 62 is further coupled between the second connection node 72 and the RF system control circuitry 56.
  • the first tunable RF filter path 66 is a first RF receive filter, such that the first RF antenna 16 forwards a first received RF signal via the first common connection node 74 to provide a first upstream RF receive signal RU1 to the first tunable RF filter path 66, which receives and filters the first upstream RF receive signal RU1 to provide a first filtered RF receive signal RF1 to the RF receive circuitry 62.
  • the second tunable RF filter path 68 is a second RF receive filter, such that the first RF antenna 16 forwards a second received RF signal via the first common connection node 74 to provide a second upstream RF receive signal RU2 to the second tunable RF filter path 68, which receives and filters the second upstream RF receive signal RU2 to provide a second filtered RF receive signal RF2 to the RF receive circuitry 62.
  • the RF receive circuitry 62 may include down-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the RF receive circuitry 62 processes the first filtered RF receive signal RF1 to provide a first receive signal RX1 to the RF system control circuitry 56. Additionally, the RF receive circuitry 62 processes the second filtered RF receive signal RF2 to provide a second receive signal RX2 to the RF system control circuitry 56.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 do not significantly load one another at frequencies of interest. As such, by directly coupling the first tunable RF filter path 66 and the second tunable RF filter path 68 to the first common connection node 74; front-end RF switching elements may be avoided, thereby reducing cost, size, and non-linearity; and increasing efficiency and flexibility of the RF communications circuitry 54.
  • each of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a bandpass filter having a unique center frequency.
  • the first filter parameter of each of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a unique center frequency.
  • one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a lowpass filter
  • another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a highpass filter.
  • the first filter parameter of each of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a break frequency.
  • one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a lowpass filter
  • another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a bandpass filter
  • the first filter parameter of one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a center frequency
  • the first filter parameter of another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a break frequency.
  • one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a highpass filter
  • another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a bandpass filter
  • the first filter parameter of one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a center frequency
  • the first filter parameter of another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a break frequency.
  • the RF communications circuitry 54 is a receive only CA system, such that the first tunable RF filter path 66, which is the first RF receive filter, and the second tunable RF filter path 68, which is the second RF receive filter, simultaneously receive and filter the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2, respectively, via the first common connection node 74.
  • the first RF filter structure 60 functions as a de-multiplexer.
  • each of the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2 has a unique carrier frequency.
  • receive CA may increase an effective receive bandwidth of the RF communications circuitry 54.
  • the RF communications circuitry 54 is a receive only communications system, such that the first tunable RF filter path 66, which is the first RF receive filter, and the second tunable RF filter path 68, which is the second RF receive filter, do not simultaneously receive and filter the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2, respectively.
  • the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2 are nonsimultaneous signals.
  • Each of the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2 may be associated with a unique RF communications band.
  • Figure 8 shows the RF communications circuitry 54 according to an alternate embodiment of the RF communications circuitry 54.
  • the RF receive circuitry 62 is omitted and the RF transmit circuitry 64 is included.
  • the RF system control circuitry 56 provides the front-end control signal FEC to the RF front-end control circuitry 98.
  • the RF front-end control circuitry 98 provides the first filter control signal FCS1 and the second filter control signal FCS2 based on the front-end control signal FEC.
  • the RF system control circuitry 56 provides the first filter control signal FCS1 and the second filter control signal FCS2 directly.
  • the RF communications circuitry 54 includes control circuitry, which may be either the RF system control circuitry 56 or the RF front-end control circuitry 98, that provides the first filter control signal FCS1 and the second filter control signal FCS2.
  • the control circuitry tunes a first filter parameter of the first tunable RF filter path 66 using the first filter control signal FCS1 . Additionally, the control circuitry tunes a first filter parameter of the second tunable RF filter path 68 using the second filter control signal FCS2. In an additional embodiment of the RF communications circuitry 54, the control circuitry further tunes a second filter parameter of the first tunable RF filter path 66 using the first filter control signal FCS1 ; and the control circuitry further tunes a second filter parameter of the second tunable RF filter path 68 using the second filter control signal FCS2.
  • any or all of the first connection node 70, the second connection node 72, and the first common connection node 74 are external to the first RF filter structure 60.
  • the first tunable RF filter path 66 includes a first pair (not shown) of weakly coupled resonators.
  • the second tunable RF filter path 68 includes a second pair (not shown) of weakly coupled resonators.
  • the first tunable RF filter path 66 is directly coupled between the first common connection node 74 and the first connection node 70
  • the second tunable RF filter path 68 is directly coupled between the second connection node 72 and the first common connection node 74
  • the first RF antenna 16 is directly coupled to the first common connection node 74.
  • the first RF antenna 16 is omitted.
  • the RF transmit circuitry 64 is coupled between the first connection node 70 and the RF system control circuitry 56, and the RF transmit circuitry 64 is further coupled between the second connection node 72 and the RF system control circuitry 56.
  • the first tunable RF filter path 66 is a first RF transmit filter, such that the RF system control circuitry 56 provides the first transmit signal TX1 to the RF transmit circuitry 64, which processes the first transmit signal TX1 to provide a first upstream RF transmit signal TU1 to the first tunable RF filter path 66.
  • the second tunable RF filter path 68 is a second RF transmit filter, such that the RF system control circuitry 56 provides a second transmit signal TX2 to the RF transmit circuitry 64, which processes the second transmit signal TX2 to provide a second upstream RF transmit signal TU2 to the second tunable RF filter path 68.
  • the RF transmit circuitry 64 may include up-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the first tunable RF filter path 66 receives and filters the first upstream RF transmit signal TU1 to provide the first filtered RF transmit signal TF1 , which is transmitted via the first common connection node 74 by the first RF antenna 16.
  • the second tunable RF filter path 68 receives and filters the second upstream RF transmit signal TU2 to provide a second filtered RF transmit signal TF2, which is transmitted via the first common connection node 74 by the first RF antenna 16.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 do not significantly load one another at frequencies of interest. As such, by directly coupling the first tunable RF filter path 66 and the second tunable RF filter path 68 to the first common connection node 74; front-end RF switching elements may be avoided, thereby reducing cost, size, and non-linearity; and increasing efficiency and flexibility of the RF communications circuitry 54.
  • each of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a bandpass filter having a unique center frequency.
  • the first filter parameter of each of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a unique center frequency.
  • one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a lowpass filter
  • another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a highpass filter.
  • the first filter parameter of each of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a break frequency.
  • one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a lowpass filter
  • another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a bandpass filter
  • the first filter parameter of one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a center frequency
  • the first filter parameter of another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a break frequency.
  • one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a highpass filter
  • another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a bandpass filter
  • the first filter parameter of one of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a center frequency
  • the first filter parameter of another of the first tunable RF filter path 66 and the second tunable RF filter path 68 is a break frequency.
  • the RF communications circuitry 54 is a transmit only CA system, such that the first tunable RF filter path 66, which is the first RF transmit filter, and the second tunable RF filter path 68, which is the second RF transmit filter, simultaneously receive and filter the first upstream RF transmit signal TU1 and the second upstream RF transmit signal TU2, respectively, to simultaneously provide the first filtered RF transmit signal TF1 and the second filtered RF transmit signal TF2, respectively, via the first common connection node 74.
  • the first RF filter structure 60 functions as a multiplexer.
  • each of the first filtered RF transmit signal TF1 and the second filtered RF transmit signal TF2 has a unique carrier frequency.
  • Using transmit CA may increase an effective transmit bandwidth of the RF communications circuitry 54.
  • the RF communications circuitry 54 is a transmit only communications system, such that the first tunable RF filter path 66, which is the first RF transmit filter, and the second tunable RF filter path 68, which is the second RF transmit filter, do not simultaneously receive and filter the first upstream RF transmit signal TU1 and the second upstream RF transmit signal TU2, respectively.
  • the first filtered RF transmit signal TF1 and the second filtered RF transmit signal TF2 are nonsimultaneous signals.
  • Each of the first filtered RF transmit signal TF1 and the second filtered RF transmit signal TF2 may be associated with a unique RF communications band.
  • Figures 9A and 9B are graphs illustrating filtering characteristics of the first tunable RF filter path 66 and the second tunable RF filter path 68, respectively, illustrated in Figure 8 according to an additional embodiment of the first tunable RF filter path 66 and the second tunable RF filter path 68, respectively.
  • Figure 9A shows a frequency response curve 100 of the first tunable RF filter path 66
  • Figure 9B shows a frequency response curve 102 of the second tunable RF filter path 68.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 are both bandpass filters having the frequency response curves 100, 102 illustrated in Figures 9A and 9B, respectively.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 can be directly coupled to one another via the first common connection node 74 ( Figure 8) without interfering with one another.
  • Figures 10A and 10B are graphs illustrating filtering characteristics of the first traditional RF duplexer 30 and the second traditional RF duplexer 36, respectively, illustrated in Figure 3 according to the prior art.
  • Figure 10A shows a frequency response curve 104 of the first traditional RF duplexer 30
  • Figure 10B shows a frequency response curve 106 of the second traditional RF duplexer 36.
  • interference 108 between the frequency response curve 104 of the first traditional RF duplexer 30 and the frequency response curve 106 of the second traditional RF duplexer 36 as shown in Figures 10A and 10B.
  • the first traditional RF duplexer 30 and the second traditional RF duplexer 36 cannot be directly coupled to one another without interfering with one another.
  • traditional systems use RF switches to disconnect unused filters.
  • Figure 1 1 shows the RF communications circuitry 54 according to one embodiment of the RF communications circuitry 54.
  • the RF communications circuitry 54 illustrated in Figure 1 1 is similar to the RF communications circuitry 54 illustrated in Figure 8, except in the RF communications circuitry 54 illustrated in Figure 1 1 , the RF front-end circuitry 58 further includes the RF receive circuitry 62 and the first RF filter structure 60 further includes a third tunable RF filter path 1 10 and a fourth tunable RF filter path 1 12.
  • the RF front-end circuitry 58 has the first connection node 70, the second connection node 72, the first common connection node 74, a third connection node 1 14 and a fourth connection node 1 16, such that all of the first connection node 70, the second connection node 72, the first common connection node 74, the third connection node 1 14 and the fourth connection node 1 16 are external to the first RF filter structure 60.
  • connection node 74, a third connection node 1 14 and a fourth connection node 1 16 are internal to the first RF filter structure 60.
  • the RF front-end control circuitry 98 further provides a third filter control signal FCS3 to the third tunable RF filter path 1 10 and a fourth filter control signal FCS4 to the fourth tunable RF filter path 1 12 based on the front- end control signal FEC.
  • the control circuitry tunes a first filter parameter of the third tunable RF filter path 1 10 using the third filter control signal FCS3. Additionally, the control circuitry tunes a first filter parameter of the fourth tunable RF filter path 1 12 using the fourth filter control signal FCS4.
  • control circuitry further tunes a second filter parameter of the third tunable RF filter path 1 10 using the third filter control signal FCS3; and the control circuitry further tunes a second filter parameter of the fourth tunable RF filter path 1 12 using the fourth filter control signal FCS4.
  • the third tunable RF filter path 1 10 includes a third pair (not shown) of weakly coupled resonators.
  • the fourth tunable RF filter path 1 12 includes a fourth pair (not shown) of weakly coupled resonators.
  • the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is directly coupled between the first common connection node 74 and the third connection node 1 14, and the fourth tunable RF filter path 1 12 is directly coupled between the fourth connection node 1 16 and the first common connection node 74.
  • the first RF antenna 16 is omitted.
  • the RF receive circuitry 62 is coupled between the third connection node 1 14 and the RF system control circuitry 56, and the RF receive circuitry 62 is further coupled between the fourth connection node 1 16 and the RF system control circuitry 56.
  • the third tunable RF filter path 1 10 is the first RF receive filter, such that the first RF antenna 16 forwards a first received RF signal via the first common connection node 74 to provide the first upstream RF receive signal RU1 to the third tunable RF filter path 1 10, which receives and filters the first upstream RF receive signal RU1 to provide the first filtered RF receive signal RF1 to the RF receive circuitry 62.
  • the fourth tunable RF filter path 1 12 is a second RF receive filter, such that the first RF antenna 16 forwards a second received RF signal via the first common connection node 74 to provide the second upstream RF receive signal RU2 to the fourth tunable RF filter path 1 12, which receives and filters the second upstream RF receive signal RU2 to provide the second filtered RF receive signal RF2 to the RF receive circuitry 62.
  • the RF receive circuitry 62 may include down-conversion circuitry, amplification circuitry, power supply circuitry, filtering circuitry, switching circuitry, combining circuitry, splitting circuitry, dividing circuitry, clocking circuitry, the like, or any combination thereof.
  • the RF receive circuitry 62 processes the first filtered RF receive signal RF1 to provide the first receive signal RX1 to the RF system control circuitry 56. Additionally, the RF receive circuitry 62 processes the second filtered RF receive signal RF2 to provide the second receive signal RX2 to the RF system control circuitry 56.
  • the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, and the fourth tunable RF filter path 1 12 do not significantly load one another at frequencies of interest.
  • front-end RF switching elements may be avoided, thereby reducing cost, size, and non-linearity; and increasing efficiency and flexibility of the RF communications circuitry 54.
  • each of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a bandpass filter having a unique center frequency.
  • the first filter parameter of each of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a unique center frequency.
  • one of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a lowpass filter, and another of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a highpass filter.
  • the first filter parameter of each of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a break frequency.
  • one of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a lowpass filter
  • another of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a bandpass filter
  • the first filter parameter of one of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a center frequency
  • the first filter parameter of another of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a break frequency.
  • one of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a highpass filter
  • another of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a bandpass filter
  • the first filter parameter of one of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a center frequency
  • the first filter parameter of another of the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 is a break frequency.
  • the RF communications circuitry 54 is a CA system, such that the third tunable RF filter path 1 10, which is the first RF receive filter, and the fourth tunable RF filter path 1 12, which is the second RF receive filter, simultaneously receive and filter the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2, respectively, via the first common connection node 74.
  • the first RF filter structure 60 functions as a de-multiplexer using the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12.
  • the first RF filter structure 60 further functions as a multiplexer using the first tunable RF filter path 66 and the second tunable RF filter path 68.
  • each of the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2 has a unique carrier frequency.
  • the RF communications circuitry 54 is a receive communications system, such that the third tunable RF filter path 1 10, which is the first RF receive filter, and the fourth tunable RF filter path 1 12, which is the second RF receive filter, do not
  • first upstream RF receive signal RU1 and the second upstream RF receive signal RU2 are nonsimultaneous signals.
  • Each of the first upstream RF receive signal RU1 and the second upstream RF receive signal RU2 may be associated with a unique RF communications band.
  • Figure 12 shows the RF communications circuitry 54 according to an alternate embodiment of the RF communications circuitry 54.
  • the communications circuitry 54 illustrated in Figure 1 2 further includes the second RF antenna 32. Additionally, the RF front-end circuitry 58 further includes a second common connection node 1 18 and a second RF filter structure 120. The third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 are included in the second RF filter structure 120 instead of being included in the first RF filter structure 60. Instead of being coupled to the first common connection node 74, the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 are coupled to the second common connection node 1 18. In one
  • the third tunable RF filter path 1 10 and the fourth tunable RF filter path 1 12 are directly coupled to the second common connection node 1 18.
  • the second RF antenna 32 is coupled to the second common connection node 1 18.
  • Figure 13 shows the RF communications circuitry 54 according to an additional embodiment of the RF communications circuitry 54.
  • the RF front-end control circuitry 98 provides a front-end status signal FES to the RF system control circuitry 56. Additionally, the RF front-end control circuitry 98 provides a first calibration control signal CCS1 and up to and including an N TH calibration control signal CCSN to the first RF filter structure 60. The RF front-end control circuitry 98 provides a PTM calibration control signal CCSP and up to and including an X TH calibration control signal CCSX to the second RF filter structure 120. Details of the first RF filter structure 60 and the second RF filter structure 120 are not shown to simplify Figure 13.
  • the first RF filter structure 60 provides a first calibration status signal CSS1 and up to and including a QTM calibration status signal CSSQ to the RF front-end control circuitry 98.
  • the second RF filter structure 120 provides an RTM calibration status signal CSSR and up to and including a YTM calibration status signal CSSY to the RF front-end control circuitry 98.
  • any or all of the N TH calibration control signal CCSN, the Q calibration status signal CSSQ, the X calibration control signal CCSX, and the Y TH calibration status signal CSSY are omitted.
  • the RF front-end circuitry 58 operates in one of a normal operating mode and a calibration mode.
  • the RF front-end control circuitry 98 performs a calibration of the first RF filter structure 60, the second RF filter structure 120, or both.
  • the RF front-end control circuitry 98 provides any or all of the filter control signals FCS1 , FCS2, FCS3, FCS4 and any or all of the calibration control signals CCS1 , CCSN, CCSP, CCSX needed for calibration.
  • the RF front-end control circuitry 98 receives any or all of the calibration status signals CSS1 , CSSQ, CSSR, CSSY needed for calibration.
  • the RF front-end control circuitry 98 provides any or all of the filter control signals FCS1 , FCS2, FCS3, FCS4 and any or all of the calibration control signals CCS1 , CCSN, CCSP, CCSX needed for normal operation. Further, the RF front-end control circuitry 98 receives any or all of the calibration status signals CSS1 , CSSQ, CSSR, CSSY needed for normal operation. Any or all of the calibration control signals CCS1 , CCSN, CCSP, CCSX may be based on the front-end control signal FEC. The front-end status signal FES may be based on any or all of the calibration status signals CSS1 , CSSQ, CSSR, CSSY. Further, during the normal operating mode, the RF front-end circuitry 58 processes signals as needed for normal operation. Other embodiments described in the present disclosure may be associated with normal operation.
  • the RF communications circuitry 54 illustrated in Figure 13 includes the first RF antenna 16 and the second RF antenna 32.
  • the RF communications circuitry 54 is a multiple antenna system.
  • a single-input single- output (SISO) antenna system is a system in which RF transmit signals may be transmitted from the first RF antenna 16 and RF receive signals may be received via the second RF antenna 32.
  • the antenna system in the RF communications circuitry 54 is a SISO antenna system, as illustrated in Figure 13.
  • a single-input multiple-output (SIMO) antenna system is a system in which RF transmit signals may be simultaneously transmitted from the first RF antenna 16 and the second RF antenna 32, and RF receive signals may be received via the second RF antenna 32.
  • the second RF filter structure 120 is coupled to the RF transmit circuitry 64, such that the antenna system in the RF communications circuitry 54 is a SIMO antenna system.
  • a multiple-input single-output (MISO) antenna system is a system in which RF transmit signals may be transmitted from the first RF antenna 16, and RF receive signals may be simultaneously received via the first RF antenna 16 and the second RF antenna 32.
  • the first RF filter structure 60 is coupled to the RF receive circuitry 62, such that the antenna system in the RF communications circuitry 54 is a MISO antenna system.
  • a multiple-input multiple-output (MIMO) antenna system is a system in which RF transmit signals may be simultaneously transmitted from the first RF antenna 16 and the second RF antenna 32, and RF receive signals may be simultaneously received via the first RF antenna 16 and the second RF antenna 32.
  • the second RF filter structure 120 is coupled to the RF transmit circuitry 64 and the first RF filter structure 60 is coupled to the RF receive circuitry 62, such that the antenna system in the RF communications circuitry 54 is a MIMO antenna system.
  • Figure 14 shows the RF communications circuitry 54 according to another embodiment of the RF communications circuitry 54.
  • the RF radio frequency
  • the first RF filter structure 60 further includes a fifth tunable RF filter path 122 and a sixth tunable RF filter path 124
  • the RF front-end circuitry 58 further includes a fifth connection node 126 and a sixth connection node 128.
  • the RF front-end control circuitry 98 shown in Figure 1 1 is not shown in Figure 14 to simplify Figure 14.
  • the fifth tunable RF filter path 122 the fifth tunable RF filter path 122 includes a fifth pair (not shown) of weakly coupled resonators.
  • the sixth tunable RF filter path 124 includes a sixth pair (not shown) of weakly coupled resonators.
  • the fifth tunable RF filter path 122 and the sixth tunable RF filter path 124 the fifth tunable RF filter path 122 is directly coupled between the first common connection node 74 and the fifth connection node 126, and the sixth tunable RF filter path 124 is directly coupled between the sixth connection node 128 and the first common connection node 74.
  • the first RF antenna 16 is omitted.
  • the RF receive circuitry 62 is further coupled between the sixth connection node 128 and the RF system control circuitry 56
  • the RF transmit circuitry 64 is further coupled between the fifth connection node 126 and the RF system control circuitry 56.
  • the sixth tunable RF filter path 124 is a third RF receive filter, such that the first RF antenna 16 forwards a third received RF signal via the first common connection node 74 to provide a third upstream RF receive signal RU3 to the sixth tunable RF filter path 124, which receives and filters the third upstream RF receive signal RU3 to provide a third filtered RF receive signal RF3 to the RF receive circuitry 62, which processes the third filtered RF receive signal RF3 to provide the third receive signal RX3 to the RF system control circuitry 56.
  • the fifth tunable RF filter path 122 is a third RF transmit filter, such that the RF system control circuitry 56 provides a third transmit signal TX3 to the RF transmit circuitry 64, which processes the third transmit signal TX3 to provide a third upstream RF transmit signal TU3 to the fifth tunable RF filter path 122.
  • the fifth tunable RF filter path 122 receives and filters the third upstream RF transmit signal TU3 to provide a third filtered RF transmit signal TF3, which is transmitted via the first common connection node 74 by the first RF antenna 16.
  • the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124 do not significantly load one another at frequencies of interest. Therefore, antenna switching circuitry 34, 42 ( Figure 3) may be avoided.
  • the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122 and the sixth tunable RF filter path 124 may be avoided, thereby reducing cost, size, and non-linearity; and increasing efficiency and flexibility of the RF communications circuitry 54.
  • the RF communications circuitry 54 is an FDD communications system, such that each of the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124 is a bandpass filter having a unique center frequency.
  • the first filter parameter of each of the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124 is a unique center frequency.
  • Figure 15 shows the RF communications circuitry 54 according to a further embodiment of the RF communications circuitry 54.
  • the RF radio frequency
  • the RF front-end circuitry 58 further includes an RF antenna switch 130 and the third connection node 1 14. Additionally, the first RF filter structure 60 further includes the third tunable RF filter path 1 10. Instead of the first RF antenna 16 being directly coupled to the first common connection node 74, as illustrated in Figure 4, the RF antenna switch 130 is coupled between the first RF antenna 16 and the first common connection node 74. As such, the first common connection node 74 is coupled to the first RF antenna 16 via the RF antenna switch 130.
  • the RF communications circuitry 54 is a hybrid RF communications system.
  • the RF antenna switch 130 has an antenna switch common
  • connection node 132 an antenna switch first connection node 134, an antenna switch second connection node 136, and an antenna switch third connection node 138.
  • the antenna switch common connection node 132 is coupled to the first RF antenna 16. In one embodiment of the RF antenna switch 130, the antenna switch common connection node 132 is directly coupled to the first RF antenna 16.
  • the antenna switch first connection node 134 is coupled to the first common connection node 74. In one embodiment of the RF antenna switch 130, the antenna switch first connection node 134 is directly coupled to the first common connection node 74.
  • the antenna switch second connection node 136 may be coupled to other circuitry (not shown).
  • the antenna switch third connection node 138 may be coupled to other circuitry (not shown). In another embodiment of the RF antenna switch 130, the antenna switch third connection node 138 is omitted. In a further embodiment of the RF antenna switch 130, the RF antenna switch 130 has at least one additional connection node.
  • the RF system control circuitry 56 provides a switch control signal SCS to the RF antenna switch 130. As such, the RF system control circuitry 56 selects one of the antenna switch first connection node 134, the antenna switch second connection node 136, and the antenna switch third connection node 138 to be coupled to the antenna switch common connection node 132 using the switch control signal SCS.
  • the third tunable RF filter path 1 10 is directly coupled between the first common connection node 74 and the third connection node 1 14.
  • the third tunable RF filter path 1 10 is a second RF receive filter, such that the first RF antenna 16 forwards a received RF signal via the RF antenna switch 130 and the first common connection node 74 to provide the second upstream RF receive signal RU2 to the third tunable RF filter path 1 10, which receives and filters the second upstream RF receive signal RU2 to provide the second filtered RF receive signal RF2 to the RF receive circuitry 62.
  • the RF receive circuitry 62 processes the second filtered RF receive signal RF2 to provide a second receive signal RX2 to the RF system control circuitry 56.
  • the RF system control circuitry 56 further provides the third filter control signal FCS3. As such, in one embodiment of the RF communications circuitry 54, the RF system control circuitry 56 tunes a first filter parameter of the third tunable RF filter path 1 10 using the third filter control signal FCS3. In one embodiment of the RF communications circuitry 54, the RF communications circuitry 54 uses the second tunable RF filter path 68 and the third tunable RF filter path 1 10 to provide receive CA. In an alternate embodiment of the RF communications circuitry 54, tunable RF filters allow for sharing a signal path to provide both an FDD signal path and a TDD signal path, thereby lowering front- end complexity.
  • Figure 16 shows the RF communications circuitry 54 according to one embodiment of the RF communications circuitry 54.
  • the RF communications circuitry 54 illustrated in Figure 16 is similar to the RF communications circuitry 54 illustrated in Figure 15, except in the RF communications circuitry 54 illustrated in Figure 16, the third tunable RF filter path 1 10 is omitted.
  • the RF receive circuitry 62, the RF transmit circuitry 64, and the first RF filter structure 60 are all broadband devices.
  • the RF communications circuitry 54 is broadband circuitry capable of processing RF signals having wide frequency ranges.
  • Figure 17 shows the RF communications circuitry 54 according to an alternate embodiment of the RF communications circuitry 54.
  • the RF radio frequency
  • the RF receive circuitry 62 is omitted and the RF front-end circuitry 58 further includes a first RF front-end circuit 140, a second RF front-end circuit 142, and a third RF front-end circuit 144.
  • the first RF front-end circuit 140 includes the RF transmit circuitry 64.
  • the second RF front-end circuit 142 includes the first RF filter structure 60, the first connection node 70, the second connection node 72, and the first common connection node 74.
  • the third RF front-end circuit 144 includes the RF antenna switch 130.
  • the first RF front-end circuit 140 is a first RF front-end integrated circuit (IC).
  • the second RF front-end circuit 142 is a second RF front-end IC.
  • the third RF front-end circuit 144 is a third RF front-end IC.
  • Figure 18 shows the RF communications circuitry 54 according to an additional embodiment of the RF communications circuitry 54.
  • the RF communications circuitry 54 illustrated in Figure 18 is similar to the RF
  • the RF receive circuitry 62 is omitted and the RF front-end circuitry 58 further includes the first RF front-end circuit 140 and the second RF front-end circuit 142.
  • the first RF front-end circuit 140 includes the RF transmit circuitry 64.
  • the second RF front-end circuit 142 includes the first RF filter structure 60, the RF antenna switch 130, the first connection node 70, the second connection node 72, and the first common connection node 74.
  • the first RF front-end circuit 140 is the first RF front- end IC.
  • the second RF front-end circuit 142 is the second RF front-end IC.
  • Figure 19 shows the RF communications circuitry 54 according to another embodiment of the RF communications circuitry 54.
  • the RF radio frequency
  • the RF receive circuitry 62 is omitted and the RF front-end circuitry 58 further includes the first RF front-end circuit 140.
  • the first RF front-end circuit 140 includes the RF transmit circuitry 64, the first RF filter structure 60, the RF antenna switch 130, the first connection node 70, the second connection node 72, and the first common connection node 74.
  • the first RF front-end circuit 140 is the first RF front-end IC.
  • Figure 20 shows the RF communications circuitry 54 according to a further embodiment of the RF communications circuitry 54.
  • the RF radio frequency
  • the communications circuitry 54 illustrated in Figure 20 is a TDD system, which is capable of transmitting and receiving RF signals, but not simultaneously.
  • the RF communications circuitry 54 illustrated in Figure 20 is similar to the RF communications circuitry 54 illustrated in Figure 4, except in the RF communications circuitry 54 illustrated in Figure 20, the second tunable RF filter path 68 and the second connection node 72 are omitted, and the RF front-end circuitry 58 further includes an RF transmit/receive switch 146 coupled between the first tunable RF filter path 66 and the RF receive circuitry 62, and further coupled between the first tunable RF filter path 66 and the RF transmit circuitry 64.
  • the first tunable RF filter path 66 Since the RF communications circuitry 54 does not simultaneously transmit and receive RF signals, the first tunable RF filter path 66 provides front- end transmit filtering when the RF communications circuitry 54 is transmitting RF signals and the first tunable RF filter path 66 provides front-end receive filtering when the RF communications circuitry 54 is receiving RF signals. In this regard, the first tunable RF filter path 66 processes half-duplex signals.
  • the RF transmit/receive switch 146 has a transmit/receive switch common connection node 148, a transmit/receive switch first connection node 150, and a transmit/receive switch second connection node 152.
  • the RF receive circuitry 62 is coupled between the RF system control circuitry 56 and the transmit/receive switch second connection node 152.
  • the RF transmit circuitry 64 is coupled between the RF system control circuitry 56 and the transmit/receive switch first connection node 150.
  • the first connection node 70 is coupled to the transmit/receive switch common connection node 148.
  • the RF system control circuitry 56 provides a switch control signal SCS to the RF transmit/receive switch 146. As such, the RF system control circuitry 56 selects either the transmit/receive switch first connection node 150 or the transmit/receive switch second connection node 152 to be coupled to the transmit/receive switch common connection node 148 using the switch control signal SCS. Therefore, when the RF communications circuitry 54 is transmitting RF signals, the RF transmit circuitry 64 is coupled to the first tunable RF filter path 66 and the RF receive circuitry 62 is not coupled to the first tunable RF filter path 66. Conversely, when the RF communications circuitry 54 is receiving RF signals, the RF receive circuitry 62 is coupled to the first tunable RF filter path 66 and the RF transmit circuitry 64 is not coupled to the first tunable RF filter path 66.
  • FIG. 21 illustrates an exemplary embodiment of the first RF filter structure 60.
  • the first RF filter structure 60 includes a plurality of resonators (referred to generically as elements R and specifically as elements R(i,j), where an integer i indicates a row position and an integer j indicates a column position, where 1 ⁇ i ⁇ M, 1 ⁇ j ⁇ N and M is any integer greater than 1 and N is any integer greater than to 1 . It should be noted that in alternative embodiments the number of resonators R in each row and column may be the same or different).
  • the first tunable RF filter path 66 includes row 1 of weakly coupled resonators R(1 ,1 ), R(1 ,2) through (R(1 ,N).
  • the second tunable RF filter path 68 includes row M of weakly coupled resonators R(M,1 ), R(M,2) through R(M,N). All of the weakly coupled resonators R(M,1 ), R(M,2) through R(M,N) are weakly coupled to one another.
  • the second tunable RF filter path 68 is electrically connected between terminal 204 and terminal 206. In this manner, the second tunable RF filter path 68 is configured to receive RF signals and output filtered RF signals.
  • the first RF filter structure 60 may include any number of tunable RF filter paths, such as, for example, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124, described above with respect to Figures 1 1 -14.
  • Each of the resonators R may be a tunable resonator, which allows for a resonant frequency of each of the resonators R to be varied to along a frequency range. In some embodiments, not all of the couplings between the resonators R are weak. A hybrid architecture having at least one pair of weakly coupled resonators R and strongly or moderately coupled resonators R is also possible.
  • Cross-coupling capacitive structures C are electrically connected to and between the resonators R.
  • each of the cross-coupling capacitive structures C is a variable cross-coupling capacitive structure, such as a varactor or an array of capacitors.
  • the magnetic couplings may be negligible.
  • the cross-coupling capacitive structures C may simply be provided by a capacitor with a fixed capacitance.
  • the tunable RF filter paths of the first RF filter structure 60 are independent of one another.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 are independent of one another and thus do not have cross-coupling capacitive structures C between their resonators.
  • the cross-coupling capacitive structures C do not connect any of the weakly coupled resonators R(1 ,1 ), R(1 ,2) through (R(1 ,N) to any of the weakly coupled resonators R(M,1 ), R(M,2) through (R(M,N). This provides increased isolation between the first tunable RF filter path 66 and the second tunable RF filter path 68.
  • energy transfer between two weakly coupled resonators R in the first tunable RF filter path 66 and the second tunable RF filter path 68 may be provided by multiple energy transfer components.
  • energy may be transferred between the resonators R only through mutual magnetic coupling, only through mutual electric coupling, or through both mutual electric coupling and mutual magnetic coupling.
  • all of the mutual coupling coefficients are provided as designed, but in practice, the mutual coupling coefficients also be the result of parasitics.
  • the inductors of the resonators R may also have magnetic coupling between them. A total coupling between the resonators R is given by the sum of magnetic and electric coupling.
  • the tunable RF filter paths 66, 68 are configured to adjust notches in the transfer function, which are provided by the resonators R within the tunable RF filter paths 66, 68.
  • the notches can be provided using parallel tanks connected in series or in shunt along a signal path of the first tunable RF filter path 66. To provide the notches, the parallel tanks operate approximately as an open circuit or as short circuits at certain frequencies. The notches can also be provided using multi-signal path cancellation.
  • the tunable RF filter paths 66, 68 may be smaller and/or have fewer inductors.
  • the tunable RF filter paths 66, 68 are configured to vary variable electric coupling coefficients so that parasitic couplings between the resonators R in the tunable RF filter paths 66, 68 are absorbed into a desired frequency transfer function.
  • Figure 22 illustrates an exemplary embodiment of the first tunable RF filter path 66 in the first RF filter structure 60 shown in Figure 21 . While the exemplary embodiment shown in Figure 22 is of the first tunable RF filter path 66, any of the tunable RF filter paths shown in the first RF filter structure 60 of Figure 21 may be arranged in accordance with the exemplary embodiment shown in Figure 22.
  • the first tunable RF filter path 66 shown in Figure 22 includes an embodiment of the resonator R(1 ,1 ) and an embodiment of the resonator R(1 ,2).
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled to one another.
  • the resonator R(1 ,1 ) includes an inductor 208 and a capacitive structure 210.
  • the resonator R(1 ,2) includes an inductor 212, a capacitive structure 214, and a capacitive structure 216.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are a pair of weakly coupled resonators.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled by providing the inductor 208 and the inductor 212 such that the inductor 208 and the inductor 212 are weakly magnetically coupled.
  • the inductor 212 has a maximum lateral width and a displacement between the inductor 208 and the inductor 212 is less than or equal to half the maximum lateral width of the inductor 212. As such, the inductor 208 and the inductor 212 are relatively close to one another.
  • the displacement between the inductor 208 and the inductor 212 may be measured from a geometric centroid of the inductor 208 to a geometric centroid of the inductor 212.
  • the maximum lateral width may be a maximum dimension of the inductor 212 along a plane defined by its largest winding.
  • the weak coupling between the inductor 208 and the inductor 212 is obtained through topological techniques.
  • the inductor 208 and the inductor 212 may be fully or partially aligned, where winding(s) of the inductor 208 and winding(s) of the inductor 212 are configured to provide weak coupling through cancellation.
  • a plane defining an orientation of the winding(s) of the inductor 208 and a plane defining an orientation of the winding(s) of the inductor 212 may be fully or partially orthogonal to one another.
  • Some of the magnetic couplings between the resonators R can be unidirectional (passive or active). This can significantly improve isolation (e.g., transmit and receive isolation in duplexers).
  • the first tunable RF filter path 66 is configured to change a sign of a total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2). Accordingly, the first tunable RF filter path 66 includes a cross-coupling capacitive structure C(P1 ) and a cross- coupling capacitive structure C(N1 ).
  • the cross-coupling capacitive structure C(P1 ) and the cross-coupling capacitive structure C(N1 ) are embodiments of the cross-coupling capacitive structures C described above with regard to Figure 21 .
  • the cross-coupling capacitive structure C(P1 ) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) so as to provide a positive coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross-coupling capacitive structure C(P1 ) is a variable cross-coupling capacitive structure configured to vary the positive coupling coefficient provided between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross-coupling capacitive structure C(N1 ) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) so as to provide a negative coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross- coupling capacitive structure C(N1 ) is a variable cross-coupling capacitive structure configured to vary the negative coupling coefficient provided between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the arrangement of the cross- coupling capacitive structure C(P1 ) and the cross-coupling capacitive structure C(N1 ) shown in Figure 22 is a V-bridge structure. In alternative embodiments, some or all of the cross-coupling capacitive structures is fixed (not variable).
  • the inductor 208 and the capacitive structure 210 are electrically connected in parallel. More specifically, the inductor 208 has an end 217 and an end 218, which are disposed opposite to one another. The ends 217, 218 are each electrically connected to the capacitive structure 210, which is grounded. Thus, the resonator R(1 ,1 ) is a single-ended resonator.
  • the inductor 212 is electrically connected between the capacitive structure 214 and the capacitive structure 216. More specifically, the inductor 212 has an end 220 and an end 222, which are disposed opposite to one another. The end 220 is electrically connected to the capacitive structure 214 and the end 222 is electrically connected to the capacitive structure 216. Both the capacitive structure 214 and the capacitive structure 216 are grounded.
  • the resonator R(1 ,2) is a differential resonator.
  • an inductor with a center tap can be used. The tap can be connected to ground and only a single capacitive structure can be used.
  • both an inductor and a capacitive structure may have a center tap that is grounded.
  • neither the inductor nor the capacitive structure may have a grounded center tap.
  • the inductor 208 is magnetically coupled to the inductor 212 such that an RF signal received at the end 217 of the inductor 208 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in a filtered RF signal being transmitted out the end 220 of the inductor 212 with the same voltage polarity.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the inductor 212 is magnetically coupled to the inductor 208 such that an RF signal received at the end 220 of the inductor 212 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in a filtered RF signal being transmitted out the end 217 of the inductor 208 with the same voltage polarity.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the transfer function of the first tunable RF filter path 66 is provided so as to be fully adjustable.
  • the inductors 208, 212 may be magnetically coupled so as to have a low magnetic coupling coefficient through field cancellation, with the variable positive coupling coefficient and the variable negative coupling coefficient.
  • the inductor 208 and the inductor 212 are arranged such that a mutual magnetic coupling between the inductor 208 and the inductor 212 cancel.
  • the inductor 208 and the inductor 212 are arranged such that the inductor 212 reduces a mutual magnetic coupling coefficient of the inductor 208.
  • the variable positive coupling coefficient is a variable positive electric coupling coefficient
  • the variable negative coupling coefficient is a variable negative electric coupling coefficient.
  • the variable positive electric coupling coefficient and the variable negative electric coupling coefficient oppose each other to create a tunable filter characteristic.
  • the resonator R(1 ,2) is operably associated with the resonator R(1 ,1 ) such that an energy transfer factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) is less than 10%.
  • a total mutual coupling between the resonator R(1 ,1 ) and the resonator R(1 ,2) is provided by a sum total of the mutual magnetic factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) and the mutual electric coupling coefficients between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the mutual magnetic coupling coefficient between the inductor 208 and the inductor 212 is a fixed mutual magnetic coupling coefficient.
  • embodiments of the resonators R(1 ,1 ), R(1 ,2) may be provided so as to provide a variable magnetic coupling coefficient between the resonators R(1 ,1 ), R(1 ,2)
  • embodiments of the resonators R(1 ,1 ), R(1 ,2) that provide variable magnetic couplings can be costly and difficult to realize.
  • providing variable electric coupling coefficients i.e., the variable positive electric coupling coefficient and the variable electric negative coupling coefficient
  • the cross- coupling capacitive structure C(P1 ) and the cross-coupling capacitive structure C(N1 ) to provide the variable positive electric coupling coefficient and the variable electric negative coupling coefficient is an economical technique for providing a tunable filter characteristic between the resonators R(1 ,1 ), R(1 ,2). Furthermore, since the mutual magnetic coupling coefficient between the inductor 208 and the inductor 212 is fixed, the first tunable RF filter path 66 has lower insertion losses.
  • the inductor 208 and the 212 inductor are the same size.
  • the inductor 208 and the inductor 212 may be different sizes.
  • the inductor 212 may be smaller than the inductor 208.
  • the magnetic coupling coefficient between the inductor 208 and the inductor 212 can be set.
  • the inductor 208 may be a folded inductor configured to generate a first confined magnetic field
  • the inductor 212 may be a folded inductor configured to generate a second confined magnetic field.
  • Magnetic field lines of the first confined magnetic field and of the second confined magnetic field that are external to the inductor 208 and inductor 212 are cancelled by opposing magnetic field lines in all directions.
  • the folded inductors can be stacked. This allows building the first tunable RF filter path 66 such that several inductors 208, 212 are stacked.
  • this arrangement allows for a specially sized interconnect structure that electrically connects the inductors 208, 212 to the capacitive structure 210, the capacitive structure 214, the capacitive structure 216, the cross-coupling capacitive structure C(P1 ), and the cross-coupling capacitive structure C(N1 ).
  • the specially sized interconnect increases the Q factor of the capacitive structure 210, the capacitive structure 214, the capacitive structure 216, the cross-coupling capacitive structure C(P1 ), and the cross-coupling capacitive structure C(N1 ), and allows for precise control of their variable capacitances.
  • Weakly coupled filters can also be realized with planar field cancellation structures.
  • Figure 23 illustrates an exemplary embodiment of the first tunable RF filter path 66 in the first RF filter structure 60 shown in Figure 21 . While the exemplary embodiment shown in Figure 23 is of the first tunable RF filter path 66, any of the tunable RF filter paths shown in the first RF filter structure 60 of Figure 21 may be arranged in accordance with the exemplary embodiment shown in Figure 23.
  • the first tunable RF filter path 66 shown in Figure 23 includes an embodiment of the resonator R(1 ,1 ) and an embodiment of the resonator R(1 ,2).
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled to one another.
  • the embodiment of the resonator R(1 ,2) is the same as the embodiment of the resonator R(1 ,2) shown in Figure 22.
  • the resonator R(1 ,2) shown in Figure 23 is a differential resonator that includes the inductor 212, the capacitive structure 214, and the capacitive structure 216.
  • the embodiment of the resonator R(1 ,1 ) shown in Figure 23 includes the inductor 208 and the capacitive structure 210.
  • the resonator R(1 ,1 ) shown in Figure 23 is a differential resonator and further includes a capacitive structure 224.
  • the end 217 of the inductor 208 is electrically connected to the capacitive structure 210 and the end 218 of the inductor 208 is electrically connected to the capacitive structure 224.
  • Both the capacitive structure 210 and the capacitive structure 224 are grounded.
  • the capacitive structure 224 is also a variable capacitive structure, such as a programmable array of capacitors or a varactor. Alternatively, a center tap of an inductor may be grounded.
  • the inductor and a capacitive structure may be RF floating (a low-resistance connection to ground).
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are a pair of weakly coupled resonators.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled by providing the inductor 208 and the inductor 212 such that the inductor 208 and the inductor 212 are weakly coupled.
  • the inductor 208 and the inductor 212 may have a magnetic coupling coefficient that is less than or equal to approximately 0.3.
  • a displacement between the inductor 208 and the inductor 212 is less than or equal to half the maximum lateral width of the inductor 212.
  • the displacement between the inductor 208 and the inductor 212 may be measured from a geometric centroid of the inductor 208 to a geometric centroid of the inductor 212.
  • the maximum lateral width may be a maximum dimension of the inductor 212 along a plane defined by its largest winding.
  • the weak coupling between the inductor 208 and the inductor 212 is obtained through topological techniques.
  • the inductor 208 and the inductor 212 may be fully or partially aligned, where winding(s) of the inductor 208 and winding(s) of the inductor 212 are configured to provide weak coupling through cancellation.
  • a plane defining an orientation of the windings of the inductor 208 and a plane defining an orientation of the windings of the inductor 212 may be fully or partially orthogonal to one another.
  • the resonator R(1 ,2) is operably associated with the resonator R(1 ,1 ) such that an energy transfer factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) is less than 10%.
  • To provide a tuning range to tune a transfer function of the first tunable RF filter path 66 such to provide a fast roll-off from a low-frequency side to a high-frequency side requires changing a sign of the total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the first tunable RF filter path 66 shown in Figure 23 includes the cross- coupling capacitive structure C(P1 ) and the cross-coupling capacitive structure C(N1 ).
  • the cross-coupling capacitive structure C(P1 ) and the cross-coupling capacitive structure C(N1 ) are arranged in the same manner described above with respect to Figure 22.
  • the first tunable RF filter path 66 shown in Figure 23 also includes a cross-coupling capacitive structure C(P2) and a cross-coupling capacitive structure C(N2).
  • the cross-coupling capacitive structure C(P2) and the cross-coupling capacitive structure C(N2) are also embodiments of the cross-coupling capacitive structures C described above with regard to Figure 21 .
  • the cross-coupling capacitive structure C(P1 ) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) so as to provide the positive coupling coefficient (i.e., the variable positive electric coupling coefficient) between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the positive coupling coefficient i.e., the variable positive electric coupling coefficient
  • the cross-coupling capacitive structure C(N1 ) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) so as to provide the negative coupling coefficient (i.e., the variable negative electric coupling coefficient) between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the negative coupling coefficient i.e., the variable negative electric coupling coefficient
  • the cross-coupling capacitive structure C(P2) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) so as to provide another positive coupling coefficient (i.e., another variable positive electric coupling coefficient) between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross-coupling capacitive structure C(P2) is electrically connected between the end 218 of the inductor 208 and the end 222 of the inductor 212.
  • the cross-coupling capacitive structure C(P2) is a variable cross-coupling capacitive structure configured to vary the other positive coupling coefficient (i.e., the other variable positive electric coupling coefficient) provided between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross-coupling capacitive structure C(N2) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) so as to provide another negative coupling coefficient (i.e., another variable negative electric coupling coefficient) between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross-coupling capacitive structure C(N2) is electrically connected between the end 218 of the inductor 208 and the end 220 of the inductor 212.
  • the cross-coupling capacitive structure C(N2) is a variable cross-coupling capacitive structure configured to vary the negative coupling coefficient (i.e., the other variable negative electric coupling coefficient) provided between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the resonator R(1 ,2) is operably associated with the resonator R(1 ,1 ) such that an energy transfer factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) is less than 10%.
  • the total mutual coupling between the resonator R(1 ,1 ) and the resonator R(1 ,2) is provided by a sum total of the mutual magnetic factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) and the mutual electric coupling coefficients between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the total mutual coupling between the resonator R(1 ,1 ) and the resonator R(1 ,2) is provided by the sum total of the mutual magnetic coupling coefficient, the variable positive electric coupling coefficient provided by the cross-coupling capacitive structure C(P1 ), the variable negative electric coupling coefficient provided by the cross-coupling capacitive structure C(N1 ), the other variable positive electric coupling coefficient provided by the cross-coupling capacitive structure C(P2), and the other variable negative electric coupling coefficient provided by the cross-coupling capacitive structure C(N2).
  • Figure 24 illustrates an exemplary embodiment of the first tunable RF filter path 66 in the first RF filter structure 60 shown in Figure 21 . While the exemplary embodiment shown in Figure 24 is of the first tunable RF filter path 66, any of the tunable RF filter paths shown in the first RF filter structure 60 of Figure 21 may be arranged in accordance with the exemplary embodiment shown in Figure 24.
  • the first tunable RF filter path 66 shown in Figure 24 includes an embodiment of the resonator R(1 ,1 ) and an embodiment of the resonator R(1 ,2).
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled to one another.
  • the embodiment of the resonator R(1 ,1 ) is the same as the embodiment of the resonator R(1 ,1 ) shown in Figure 22.
  • the resonator R(1 ,1 ) shown in Figure 24 is a single-ended resonator that includes the inductor 208 and the capacitive structure 210.
  • the embodiment of the resonator R(1 ,2) shown in Figure 24 includes the inductor 212 and the capacitive structure 214.
  • the resonator R(1 ,2) shown in Figure 24 is a single-ended resonator. More specifically, the end 220 and the end 222 of the inductor 212 are each electrically connected to the capacitive structure 214, which is grounded.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are a pair of weakly coupled resonators.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled by providing the inductor 208 and the inductor 212 such that the inductor 208 and the inductor 212 are weakly coupled.
  • the inductor 208 and the inductor 212 may have a magnetic coupling coefficient that is less than or equal to approximately 0.3.
  • the displacement between the inductor 208 and the inductor 212 is less than or equal to half the maximum lateral width of the inductor 212.
  • the inductor 208 and the inductor 212 are relatively close to one another.
  • the displacement between the inductor 208 and the inductor 212 may be measured from the geometric centroid of the inductor 208 to the geometric centroid of the inductor 212.
  • the maximum lateral width may be a maximum dimension of the inductor 212 along a plane defined by its largest winding.
  • the weak coupling between the inductor 208 and the inductor 212 is obtained through topological techniques.
  • the inductor 208 and the inductor 212 may be fully or partially aligned, where winding(s) of the inductor 208 and winding(s) of the inductor 212 are configured to provide weak coupling through cancellation.
  • a plane defining an orientation of the windings of the inductor 208 and a plane defining an orientation of the windings of the inductor 212 may be fully or partially orthogonal to one another.
  • the resonator R(1 ,2) is operably associated with the resonator R(1 ,1 ) such that an energy transfer factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) is less than 10%.
  • the first tunable RF filter path 66 is configured to change a sign of a total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the first tunable RF filter path 66 shown in Figure 24 only includes the cross-coupling capacitive structure C(P1 ), which is electrically connected between the end 217 of the inductor 208 and the end 220 of the inductor 212.
  • the cross- coupling capacitive structure C(P1 ) is a variable cross-coupling capacitive structure configured to vary the positive coupling coefficient (i.e., the variable positive electric coupling coefficient) provided between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the inductor 208 and the inductor 212 are arranged so as to provide a fixed negative mutual magnetic coupling coefficient between the inductor 208 of the resonator R(1 ,1 ) and the inductor 212 of the resonator R(1 ,2).
  • varying the variable positive electric coupling coefficient allows for the sign of the total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2) to be changed using only the cross-coupling capacitive structure C(P1 ).
  • the inductor 208 is magnetically coupled to the inductor 212 such that an RF signal received at the end 217 of the inductor 208 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in a filtered RF signal with the same voltage polarity being transmitted out the end 222 of the inductor 212.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the inductor 212 is magnetically coupled to the inductor 208 such that an RF signal received at the end 222 of the inductor 212 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in a filtered RF signal with the same voltage polarity being transmitted out the end 217 of the inductor 208.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the transfer function of the first tunable RF filter path 66 is provided so to be fully adjustable.
  • the arrangement of the cross-coupling capacitive structure C(P1 ) shown in Figure 24 is a single positive bridge structure.
  • Figure 25 illustrates another exemplary embodiment of the first tunable RF filter path 66 in the first RF filter structure 60 shown in Figure 21 . While the exemplary embodiment shown in Figure 25 is of the first tunable RF filter path 66, any of the tunable RF filter paths shown in the first RF filter structure 60 of Figure 21 may be arranged in accordance with the exemplary embodiment shown in Figure 25.
  • the first tunable RF filter path 66 shown in Figure 25 includes an embodiment of the resonator R(1 ,1 ) and an embodiment of the resonator R(1 ,2).
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled to one another.
  • the embodiment of the resonator R(1 ,1 ) is the same as the embodiment of the resonator R(1 ,1 ) shown in Figure 22.
  • the resonator R(1 ,1 ) shown in Figure 25 is a single-ended resonator that includes the inductor 208 and the capacitive structure 210, which are arranged in the same manner described above with respect to Figure 22.
  • the resonator R(1 ,2) shown in Figure 25 is a single-ended resonator that includes the inductor 212 and the capacitive structure 214.
  • the inductor 208 shown in Figure 25 is magnetically coupled to the inductor 212 such that an RF signal received at the end 217 of the inductor 208 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in a filtered RF signal with the same voltage polarity being transmitted out the end 220 of the inductor 212.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the inductor 212 shown in Figure 25 is magnetically coupled to the inductor 208 such that an RF signal received at the end 220 of the inductor 212 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in a filtered RF signal with the same voltage polarity being transmitted out the end 217 of the inductor 208.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the resonator R(1 ,2) is a differential resonator.
  • the resonator R(1 ,1 ) is a single-ended resonator while the resonator R(1 ,2) is a differential resonator.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are a pair of weakly coupled resonators.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are weakly coupled by providing the inductor 208 and the inductor 212 such that the inductor 208 and the inductor 212 are weakly coupled.
  • the inductor 208 and the inductor 212 may have a fixed magnetic coupling coefficient that is less than or equal to approximately 0.3.
  • a displacement between the inductor 208 and the inductor 212 is less than or equal to half the maximum lateral width of the inductor 212.
  • the displacement between the inductor 208 and the inductor 212 may be measured from a geometric centroid of the inductor 208 to a geometric centroid of the inductor 212.
  • the maximum lateral width may be a maximum dimension of the inductor 212 along a plane defined by its largest winding.
  • the weak coupling between the inductor 208 and the inductor 212 is obtained through topological techniques.
  • the inductor 208 and the inductor 212 may be fully or partially aligned, where winding(s) of the inductor 208 and winding(s) of the inductor 212 are configured to provide weak coupling through cancellation.
  • a plane defining an orientation of the windings of the inductor 208 and a plane defining an orientation of the windings of the inductor 212 may be fully or partially orthogonal to one another.
  • the resonator R(1 ,2) is operably associated with the resonator R(1 ,1 ) such that an energy transfer factor between the resonator R(1 ,1 ) and the resonator R(1 ,2) is less than 10%.
  • the first tunable RF filter path 66 is configured to change the sign of the total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the first tunable RF filter path 66 shown in Figure 25 includes a cross-coupling capacitive structure C(PH1 ), a cross-coupling capacitive structure (CNH1 ), a cross-coupling capacitive structure C(I1 ), a cross-coupling capacitive structure C(PH2), and a cross-coupling capacitive structure C(NH2).
  • cross- coupling capacitive structure C(PH1 ), the cross-coupling capacitive structure (CNH1 ), the cross-coupling capacitive structure C(I1 ), the cross-coupling capacitive structure C(PH2), and the cross-coupling capacitive structure C(NH2) are also embodiments of the cross-coupling capacitive structures C described above with regard to Figure 21 .
  • the cross-coupling capacitive structure C(PH1 ) and the cross-coupling capacitive structure C(NH1 ) are arranged to form a first capacitive voltage divider.
  • the first capacitive voltage divider is electrically connected to the resonator R(1 ,1 ). More specifically, the cross-coupling capacitive structure C(PH1 ) is electrically connected between the end 217 of the inductor 208 and a common connection node H1 .
  • the cross-coupling capacitive structure C(NH1 ) is electrically connected between the end 218 of the inductor 208 and the common connection node H1 . Additionally, the cross-coupling capacitive structure
  • the cross-coupling capacitive structure C(PH2) and the cross-coupling capacitive structure C(NH2) are arranged to form a second capacitive voltage divider.
  • the second capacitive voltage divider is electrically connected to the resonator R(1 ,2).
  • the cross- coupling capacitive structure C(PH2) is electrically connected between the end 220 of the inductor 212 and a common connection node H2.
  • the cross-coupling capacitive structure C(NH2) is electrically connected between the end 222 of the inductor 212 and the common connection node H2.
  • the cross-coupling capacitive structure C(I1 ) is electrically connected between the first capacitive voltage divider and the second capacitive voltage divider.
  • the cross-coupling capacitive structure C(I1 ) is electrically connected between the common connection node H1 and the common connection node H2.
  • the arrangement of the cross-coupling capacitive structure C(PH1 ), the cross- coupling capacitive structure C(NH1 ), the cross-coupling capacitive structure C(PH2), the cross-coupling capacitive structure C(NH2), and the cross-coupling capacitive structure C(I1 ) shown in Figure 25 is an H-bridge structure.
  • the cross-coupling capacitive structure C(I1 ) is not provided and instead there is a short between the common connection node H1 and the common connection node H2.
  • a center tap of the inductor 208 may be grounded and/or the common connection node H1 may be
  • a high impedance to ground may be provided at the common connection node H1 .
  • the cross-coupling capacitive structure C(PH1 ) is a variable cross-coupling capacitive structure configured to vary a first variable positive electric coupling coefficient provided between the resonator R(1 ,1 ) and the common connection node H1 .
  • the cross- coupling capacitive structure C(NH1 ) is a variable cross-coupling capacitive structure configured to vary a first variable negative electric coupling coefficient provided between the resonator R(1 ,1 ) and the common connection node H1 .
  • a mutual electric coupling coefficient of the resonator R(1 ,1 ) is
  • the cross- coupling capacitive structure C(PH2) is a variable cross-coupling capacitive structure configured to vary a second variable positive electric coupling
  • the cross-coupling capacitive structure C(NH2) is a variable cross- coupling capacitive structure configured to vary a second variable negative electric coupling coefficient provided between the resonator R(1 ,2) and the common connection node H2.
  • a mutual electric coupling coefficient of the resonator R(1 ,2) is approximately equal to the second variable positive electric coupling coefficient and the second variable negative electric coupling coefficient.
  • the cross-coupling capacitive structure C(I1 ) is a variable cross- coupling capacitive structure configured to vary a first variable intermediate electric coupling coefficient provided between the common connection node H1 and the common connection node H2.
  • the first tunable RF filter path 66 shown in Figure 25 thus has a total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2) equal to the sum total of the mutual magnetic coupling coefficient between the inductor 208 and the inductor 212, the mutual electric coupling coefficient of the resonator R(1 ,1 ), the mutual electric coupling coefficient of the resonator R(1 ,2), and the first variable intermediate electric coupling coefficient provided between the common connection node H1 and the common connection node H2.
  • cross-coupling capacitive structures with fixed capacitances are provided.
  • the cross-coupling capacitive structure C(PH1 ), the cross-coupling capacitive structure C(NH1 ), the cross-coupling capacitive structure C(PH2), the cross-coupling capacitive structure C(NH2), and the cross- coupling capacitive structure C(I1 ) may each be provided as a varactor.
  • the cross-coupling capacitive structure C(PH1 ), the cross-coupling capacitive structure C(NH1 ), the cross-coupling capacitive structure C(PH2), the cross-coupling capacitive structure C(NH2), and the cross-coupling capacitive structure C(I1 ) may each be provided as a programmable array of capacitors in order to reduce insertion losses and improve linearity.
  • the cross-coupling capacitive structure C(PH1 ), the cross-coupling capacitive structure C(NH1 ), the cross-coupling capacitive structure C(PH2), the cross-coupling capacitive structure C(NH2), and the cross-coupling capacitive structure C(I1 ) can also be any combination of suitable variable cross-coupling capacitive structures, such as combinations of varactors and programmable arrays of capacitors.
  • suitable variable cross-coupling capacitive structures such as combinations of varactors and programmable arrays of capacitors.
  • Figure 26 illustrates yet another exemplary embodiment of the first tunable RF filter path 66 in the first RF filter structure 60 shown in Figure 21 . While the exemplary embodiment shown in Figure 26 is of the first tunable RF filter path 66, any of the tunable RF filter paths shown in the first RF filter structure 60 of Figure 21 may be arranged in accordance with the exemplary embodiment shown in Figure 26.
  • the first tunable RF filter path 66 shown in Figure 26 can be used to ameliorate the common-mode signal transfer of the H- bridge structure shown in Figure 25.
  • the first tunable RF filter path 66 shown in Figure 26 includes the same embodiment of the resonator R(1 ,1 ) and the same embodiment of the resonator R(1 ,2) described above with respect to Figure 25. Furthermore, the first tunable RF filter path 66 shown in Figure 26 includes the first capacitive voltage divider with the cross-coupling capacitive structure C(PH1 ) and the cross-coupling capacitive structure C(NH1 ) described above with respect to Figure 25, the second capacitive voltage divider with the cross-coupling capacitive structure C(PH2) and the cross-coupling capacitive structure (CNH2) described above with respect to Figure 25, and the cross-coupling capacitive structure C(I1 ) described above with respect to Figure 25.
  • the first tunable RF filter path 66 shown in Figure 26 also includes a cross-coupling capacitive structure C(PH3), a cross- coupling capacitive structure (CNH3), a cross-coupling capacitive structure C(I2), a cross-coupling capacitive structure C(PH4), and a cross-coupling capacitive structure C(NH4).
  • cross-coupling capacitive structure C(PH3), the cross- coupling capacitive structure (CNH3), the cross-coupling capacitive structure C(I2), the cross-coupling capacitive structure C(PH4), and the cross-coupling capacitive structure C(NH4) are also embodiments of the cross-coupling capacitive structures C described above with regard to Figure 21 .
  • the cross-coupling capacitive structure C(PH3) and the cross-coupling capacitive structure C(NH3) are arranged to form a third capacitive voltage divider.
  • the third capacitive voltage divider is electrically connected to the resonator R(1 ,1 ). More specifically, the cross-coupling capacitive structure C(PH3) is electrically connected between the end 217 of the inductor 208 and a common connection node H3.
  • the cross-coupling capacitive structure C(NH3) is electrically connected between the end 218 of the inductor 208 and the common connection node H3.
  • cross-coupling capacitive structure C(PH4) and the cross-coupling capacitive structure C(NH4) are arranged to form a fourth capacitive voltage divider.
  • the fourth capacitive voltage divider is electrically connected to the resonator R(1 ,2). More
  • the cross-coupling capacitive structure C(PH4) is electrically connected between the end 220 of the inductor 212 and a common connection node H4.
  • the cross-coupling capacitive structure C(NH4) is electrically connected between the end 222 of the inductor 212 and the common connection node H4.
  • the cross-coupling capacitive structure C(I2) is electrically connected between first capacitive voltage divider and the second capacitive voltage divider. More specifically, the cross-coupling capacitive structure C(I2) is electrically connected between the common connection node H3 and the common connection node H4.
  • the cross-coupling capacitive structure C(I1 ) and the cross-coupling capacitive structure C(I2) can be replaced with shorts.
  • the arrangement of the cross-coupling capacitive structure C(PH1 ), the cross-coupling capacitive structure C(NH1 ), the cross- coupling capacitive structure C(PH2), the cross-coupling capacitive structure C(NH2), the cross-coupling capacitive structure C(I 1 ), the cross-coupling capacitive structure C(PH3), the cross-coupling capacitive structure C(NH3), the cross-coupling capacitive structure C(PH4), the cross-coupling capacitive structure C(NH4), and the cross-coupling capacitive structure C(I2) shown in Figure 26 is a double H-bridge structure.
  • the cross-coupling capacitive structure C(PH3) is a variable cross-coupling capacitive structure configured to vary a third variable positive electric coupling coefficient provided between the resonator R(1 ,1 ) and the common connection node H3.
  • the cross- coupling capacitive structure C(NH3) is a variable cross-coupling capacitive structure configured to vary a third variable negative electric coupling coefficient provided between the resonator R(1 ,1 ) and the common connection node H3.
  • a mutual electric coupling coefficient of the resonator R(1 ,1 ) is
  • the cross-coupling capacitive structure C(PH4) is a variable cross-coupling capacitive structure configured to vary a fourth variable positive electric coupling coefficient provided between the resonator R(1 ,2) and the common connection node H4.
  • the cross- coupling capacitive structure C(NH4) is a variable cross-coupling capacitive structure configured to vary a fourth variable negative electric coupling coefficient provided between the resonator R(1 ,2) and the common connection node H4.
  • a mutual electric coupling coefficient of the resonator R(1 ,2) is
  • the cross-coupling capacitive structure C(I2) is a variable cross- coupling capacitive structure configured to vary a second variable intermediate electric coupling coefficient provided between the common connection node H3 and the common connection node H4.
  • the first tunable RF filter path 66 shown in Figure 26 thus has a total mutual coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2) equal to the sum total of the mutual magnetic coupling coefficient between the inductor 208 and the inductor 212, the mutual electric coupling coefficient of the resonator R(1 ,1 ), the mutual electric coupling coefficient of the resonator R(1 ,2), the first variable intermediate electric coupling coefficient provided between the common connection node H1 and the common connection node H2 and the second variable intermediate electric coupling coefficient provided between the common connection node H3 and the common connection node H4.
  • the double H-bridge structure thus includes two H-bridge structures.
  • the two H-bridge structures allow for common-mode signal transfers of the two H-bridge structures to oppose one another and thereby be reduced and even cancelled.
  • Figure 27 illustrates still another exemplary embodiment of the first tunable RF filter path 66 in the first RF filter structure 60 shown in Figure 21 . While the exemplary embodiment shown in Figure 27 is of the first tunable RF filter path 66, any of the tunable RF filter paths shown in the first RF filter structure 60 of Figure 21 may be arranged in accordance with the exemplary embodiment shown in Figure 27.
  • the first tunable RF filter path 66 shown in Figure 27 includes the same embodiment of the resonator R(1 ,1 ) and the same embodiment of the resonator R(1 ,2) described above with respect to Figure 22.
  • the first tunable RF filter path 66 shown in Figure 27 includes the cross-coupling capacitive structure C(P1 ) and the cross-coupling capacitive structure (CN1 ) that form the V-bridge structure described above with respect to Figure 22.
  • the first tunable RF filter path 66 shown in Figure 27 further includes a resonator R(1 ,3) and a resonator R(1 ,4). More specifically, the resonator R(1 ,3) includes an inductor 226, a capacitive structure 228, and a capacitive structure 230.
  • the resonator R(1 ,4) includes an inductor 232 and a capacitive structure 234.
  • the inductor 226 is electrically connected between the capacitive structure 228 and the capacitive structure 230. More specifically, the inductor 226 has an end 236 and an end 238, which are disposed opposite to one another. The end 236 is electrically connected to the capacitive structure 228 and the end 238 is electrically connected to the capacitive structure 230. Both the capacitive structure 228 and the capacitive structure 230 are grounded. Thus, the resonator R(1 ,3) is a differential resonator. In this embodiment, each of the capacitive structure 228 and the capacitive structure 230 is a variable capacitive structure.
  • the capacitive structure 234 are electrically connected in parallel. More specifically, the inductor 232 has an end 240 and an end 242, which are disposed opposite to one another. The ends 240, 242 are each electrically connected to the
  • the resonator R(1 ,4) is a single-ended resonator.
  • the resonator R(1 ,1 ), the resonator R(1 ,2), the resonator R(1 ,3), and the resonator R(1 ,4) are all weakly coupled to one another.
  • the resonator R(1 ,3) and the resonator R(1 ,4) are weakly coupled by providing the inductor 226 and the inductor 232 such that the inductor 226 and the inductor 232 are weakly coupled.
  • the resonators R(1 ,1 ), R(1 ,2), R(1 ,3), and R(1 ,4) are each operably associated with one another such that energy transfer factors between the resonators R(1 ,1 ), R(1 ,2), R(1 ,3), and R(1 ,4) are less than 10%.
  • the inductor 232 has a maximum lateral width and a displacement between the inductor 226 and the inductor 232 is less than or equal to half the maximum lateral width of the inductor 232. As such, the inductor 226 and the inductor 232 are relatively close to one another.
  • the displacement between the inductor 226 and the inductor 232 may be measured from a geometric centroid of the inductor 226 to a geometric centroid of the inductor 232.
  • the maximum lateral width may be a maximum dimension of the inductor 232 along a plane defined by its largest winding.
  • the weak coupling between the inductor 226 and the inductor 232 is obtained through topological techniques.
  • the inductor 226 and the inductor 232 may be fully or partially aligned, where winding(s) of the inductor 226 and winding(s) of the inductor 232 are configured to provide weak coupling through cancellation.
  • a plane defining an orientation of the windings of the inductor 226 and a plane defining an orientation of the windings of the inductor 232 may be fully or partially orthogonal to one another.
  • all of the inductors 208, 212, 226, 232 are provided such that displacements between each of the inductors 208, 212, 226, 232 are less than or equal to half the maximum lateral width of the inductor 212.
  • only a proper subset of the inductors 208, 212, 226, 232 has displacements that are less than or equal to half the maximum lateral width of the inductor 212.
  • the displacement between the inductor 208 and the inductor 212 may be less than or equal to half the maximum lateral width of the inductor 212 and the displacement between the inductor 226 and the inductor 232 may be less than or equal to half the maximum lateral width of the inductor 232
  • the displacements from the inductor 208 and the inductor 212 to the inductor 226 and the inductor 232 may each be greater than half the maximum lateral width of the inductor 212 and half the maximum lateral width of the inductor 232.
  • the inductors 208, 212, 226, and 232 are magnetically coupled to the each other such that an RF signal received at the end 217 of the inductor 208 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in filtered RF signals with the same voltage polarity being transmitted out the end 220 of the inductor 212, the end 236 of the inductor 226, and the end 240 of the inductor 232.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the inductors 208, 212, 226, and 232 are magnetically coupled to the each other such that an RF signal received at the end 240 of the inductor 232 with a voltage polarity (i.e., either a positive voltage polarity or a negative voltage polarity) results in filtered RF signals with the same voltage polarity being transmitted out the end 217 of the inductor 208, the end 220 of the inductor 212, and the end 236 of the inductor 226.
  • a voltage polarity i.e., either a positive voltage polarity or a negative voltage polarity
  • the first tunable RF filter path 66 shown in Figure 27 includes a cross- coupling capacitive structure C(P3), a cross-coupling capacitive structure C(N3), a cross-coupling capacitive structure C(P4), and a cross-coupling capacitive structure C(N4) electrically connected between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P3), the cross-coupling capacitive structure C(N3), the cross-coupling capacitive structure C(P4) and the cross- coupling capacitive structure C(N4) are arranged to have the X-bridge structure described above with respect to Figure 23.
  • the cross-coupling capacitive structure C(P3) is electrically connected between the end 220 and the end 236 so as to provide a variable positive electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P3) is a variable cross-coupling capacitive structure configured to vary the variable positive electric coupling coefficient provided between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(N3) is electrically connected between the end 220 and the end 238 so as to provide a variable negative electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(N3) is a variable cross-coupling capacitive structure configured to vary the variable negative electric coupling coefficient provided between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P4) is electrically connected between the end 222 and the end 238 so as to provide another variable positive electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P4) is a variable cross-coupling capacitive structure configured to vary the other variable positive electric coupling coefficient provided between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(N4) is electrically connected between the end 222 and the end 236 so as to provide another variable negative electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(N4) is a variable cross-coupling capacitive structure configured to vary the other variable negative electric coupling coefficient provided between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the first tunable RF filter path 66 shown in Figure 27 includes a cross-coupling capacitive structure C(P5) and a cross-coupling capacitive structure C(N5) electrically connected between the resonator R(1 ,3) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(P5) and the cross-coupling capacitive structure C(N5) are arranged to have the V-bridge structure described above with respect to Figure 22.
  • the cross-coupling capacitive structure C(P5) is electrically connected between the end 236 and the end 240 so as to provide a variable positive electric coupling coefficient between the resonator R(1 ,3) and the resonator R(1 ,4).
  • the cross- coupling capacitive structure C(P5) is a variable cross-coupling capacitive structure configured to vary the variable positive electric coupling coefficient provided between the resonator R(1 ,3) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(N5) is electrically connected between the end 238 and the end 240 so as to provide a variable negative electric coupling coefficient between the resonator R(1 ,3) and the resonator R(1 ,4).
  • the cross- coupling capacitive structure C(N5) is a variable cross-coupling capacitive structure configured to vary the variable negative electric coupling coefficient provided between the resonator R(1 ,3) and the resonator R(1 ,4).
  • first RF filter structure 60 shown in Figure 27 also includes a cross-coupling capacitive structure C(P6), a cross-coupling capacitive structure C(N6), a cross-coupling capacitive structure C(P7), a cross-coupling capacitive structure C(N7), and a cross-coupling capacitive structure C(P8).
  • the cross-coupling capacitive structure C(P6) and the cross-coupling capacitive structure C(N6) are each electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P6) is electrically connected between the end 217 and the end 236 so as to provide a variable positive electric coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P6) is a variable cross-coupling capacitive structure configured to vary the variable positive electric coupling coefficient provided between the resonator R(1 ,1 ) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(N6) is electrically connected between the end 217 and the end 238 so as to provide a variable negative electric coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,3).
  • the cross- coupling capacitive structure C(N6) is a variable cross-coupling capacitive structure configured to vary the variable negative electric coupling coefficient provided between the resonator R(1 ,1 ) and the resonator R(1 ,3).
  • the cross-coupling capacitive structure C(P7) and the cross-coupling capacitive structure C(N7) are each electrically connected between the resonator R(1 ,2) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(P7) is electrically connected between the end 220 and the end 240 so as to provide a variable positive electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(P7) is a variable cross-coupling capacitive structure configured to vary the variable positive electric coupling coefficient provided between the resonator R(1 ,2) and the resonator R(1 ,4). Also, the cross-coupling capacitive structure C(N7) is electrically connected between the end 222 and the end 240 so as to provide a variable negative electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(N7) is a variable cross-coupling capacitive structure configured to vary the variable negative electric coupling coefficient provided between the resonator R(1 ,2) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(P8) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(P8) is electrically connected between the end 217 and the end 240 so as to provide a variable positive electric coupling coefficient between the resonator R(1 , 1 ) and the resonator R(1 ,4).
  • the cross-coupling capacitive structure C(P8) is a variable cross-coupling capacitive structure configured to vary the variable positive electric coupling coefficient provided between the resonator R(1 , 1 ) and the resonator R(1 ,4).
  • a variable capacitive structure 244 is electrically connected in series between the terminal 200 and the resonator R(1 , 1 ).
  • the variable capacitive structure 244 is configured to vary a variable impedance of the first tunable RF filter path 66 as measured into the terminal 200 in order to match a source or a load impedance at the terminal 200.
  • a variable capacitive structure 245 is electrically connected in series between the resonator R(1 ,4) and the terminal 202.
  • the variable capacitive structure 245 is configured to vary a variable impedance of the first tunable RF filter path 66 as seen into the terminal 202 in order to match a source or a load impedance at the terminal 202.
  • Figures 28A through 28D illustrate different embodiments of the first RF filter structure 60, wherein each of the embodiments has different
  • the first RF filter structure 60 can have various topologies.
  • the embodiment of the first RF filter structure 60 shown in Figure 28A has a single input terminal IN and an integer number i of output terminals OUT-i-OUTj.
  • the first RF filter structure 60 may define various tunable RF filter paths (e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 1 0, the fourth tunable RF filter path 1 1 2, the fifth tunable RF filter path 1 22, and the sixth tunable RF filter path 1 24 shown in Figures 4, 8, 1 1 , 12, and 14-20) that may be used to receive different RF signals at the input terminal IN and transmit a different filtered RF signal from each of the output terminals OUT-i-OUTi.
  • the first RF filter structure 60 shown in Figure 28A may be specifically configured to provide Single Input Multiple Output (SIMO) operations.
  • SIMO Single Input Multiple Output
  • the first RF filter structure 60 has an integer number j of input terminals IN-i-INj and a single output terminal OUT.
  • the first RF filter structure 60 may define various tunable RF filter paths (e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124 shown in Figures 4, 8, 1 1 , 12, and 14-20) that may be used to receive a different RF signal at each of the input terminals ⁇ - ⁇ -IN j and transmit different filtered RF signals from the single output terminal OUT.
  • the first RF filter structure 60 shown in Figure 28B may be specifically configured to provide Multiple Input Single Output (MISO) operations.
  • MISO Multiple Input Single Output
  • the first RF filter structure 60 has a single input terminal IN and a single output terminal OUT.
  • the first RF filter structure 60 may define various tunable RF filter paths (e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124 shown in Figures 4, 8, 1 1 , 12, and 14-20) that may be used to receive different RF signals at the single input terminal IN and transmit different filtered RF signals from the output terminal OUT.
  • the first RF filter structure 60 shown in Figure 28A may be specifically configured to provide Single Input Single Output (SISO) operations.
  • SISO Single Input Single Output
  • the first RF filter structure 60 has the input terminals ⁇ - ⁇ -IN j and the output terminals OUT-i-OUTj.
  • the first RF filter structure 60 may define various tunable RF filter paths (e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124 shown in Figures 4, 8, 1 1 , 12, and 14-20) that may be used to receive a different RF signal at each of the input terminal IN IN j and transmit a different filtered RF signal from each of the output terminals OUT OUTi.
  • tunable RF filter paths e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable
  • Figure 29 illustrates another embodiment of the first RF filter structure 60.
  • the first RF filter structure 60 shown in Figure 29 includes one embodiment of the first tunable RF filter path 66 and one embodiment of the second tunable RF filter path 68.
  • the first tunable RF filter path 66 includes the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) are thus a first pair of weakly coupled resonators in the first tunable RF filter path 66.
  • the second tunable RF filter path 68 includes the resonator R(2,1 ) and the resonator R(2,2).
  • the resonator R(2,1 ) and the resonator R(2,2) are thus a second pair of weakly coupled resonators in the second tunable RF filter path 68.
  • a set S of cross-coupling capacitive structures is electrically connected between the resonator R(1 ,1 ), the resonator R(1 ,2), the resonator R(2,1 ), and the resonator R(2,2) in the first tunable RF filter path 66 and the second tunable RF filter path 68.
  • the set S includes a cross-coupling capacitive structure C(PM1 ), a cross-coupling capacitive structure C(PM2), a cross-coupling capacitive structure C(PM3), a cross-coupling capacitive structure C(PM4), a cross-coupling capacitive structure C(NM1 ), and a cross-coupling capacitive structure C(NM2).
  • the set S of cross-coupling capacitive structures interconnects the resonator R(1 ,1 ), the resonator R(1 ,2), the resonator R(2,1 ), and the resonator R(2,2) so that the first RF filter structure 60 shown in Figure 29 is a matrix (in this embodiment, a 2X2 matrix) of the resonators R.
  • some of the cross-coupling capacitive structures C(PM1 ), C(PM2), C(PM3), C(PM4), C(NM1 ), and C(NM2) may be omitted depending on the filter transfer function to be provided.
  • the first tunable RF filter path 66 and the second tunable RF filter path 68 are not independent of one another.
  • the set S of cross- coupling capacitive structures thus provides for additional tunable RF filter paths to be formed from the resonator R(1 ,1 ), the resonator R(1 ,2), the resonator R(2,1 ), and the resonator R(2,2).
  • the arrangement of the first RF filter structure 60 shown in Figure 29 can be used to realize examples of each of the embodiments of the first RF filter structure 60 shown in Figures 28A-28D.
  • the cross-coupling capacitive structure C(PM1 ) is electrically connected within the first tunable RF filter path 66, while the cross-coupling capacitive structure C(PM4) is electrically connected within the second tunable RF filter path 68. More specifically, the cross-coupling capacitive structure C(PM1 ) is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2) in the first tunable RF filter path 66.
  • the cross-coupling capacitive structure C(PM1 ) is a variable cross-coupling capacitive structure configured to provide and vary a (e.g., positive or negative) electric coupling coefficient between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • the cross-coupling capacitive structure C(PM4) is a variable cross-coupling capacitive structure configured to provide and vary a (e.g., positive or negative) electric coupling coefficient between the resonator R(2,1 ) and the resonator R(2,2) in the second tunable RF filter path 68.
  • the cross-coupling capacitive structure C(PM2), the cross-coupling capacitive structure C(PM3), the cross-coupling capacitive structure C(NM1 ), and the cross-coupling capacitive structure C(NM2) are each electrically connected between the first tunable RF filter path 66 and the second tunable RF filter path 68.
  • the cross-coupling capacitive structure C(PM2) is a variable cross-coupling capacitive structure configured to provide and vary a (e.g., positive or negative) electric coupling coefficient between the resonator R(1 ,2) and the resonator R(2,2).
  • the cross- coupling capacitive structure C(PM3) is a variable cross-coupling capacitive structure configured to provide and vary a (e.g., positive or negative) electric coupling coefficient between the resonator R(1 ,1 ) and the resonator R(2,1 ).
  • the cross-coupling capacitive structure C(NM1 ) is a variable cross-coupling capacitive structure configured to provide and vary a (e.g., positive or negative) electric coupling coefficient between the resonator R(1 ,1 ) and the resonator R(2,2).
  • the cross-coupling capacitive structure C(NM2) is a variable cross- coupling capacitive structure configured to provide and vary a (e.g., positive or negative) electric coupling coefficient between the resonator R(1 ,2) and the resonator R(2,1 ).
  • the first tunable RF filter path 66 is electrically connected between the input terminal IN and the output terminal OUT-,.
  • the second tunable RF filter path 68 is electrically connected between an input terminal IN 2 and an output terminal OUT 2 .
  • the first RF filter structure 60 shown in Figure 29 is an embodiment of the first RF filter structure 60 shown in Figure 28D.
  • the input terminal IN 2 and the output terminal OUT are optional and may be excluded in other embodiments.
  • the first RF filter structure 60 shown in Figure 29 would be provided as an embodiment of the first RF filter structure 60 shown in Figure 28A. It might, for example, provide a diplexing or a duplexing function.
  • Some examples include embodiments of the first RF filter structure 60 used for triplexing, quadplexing, herplexing, and providing FDD and carrier aggregation.
  • the first tunable RF filter path 66 still provides a path between the input terminal INi and the output terminal OUT-i. However, assuming that the input terminal IN 2 is not provided for SIMO operation, the cross-coupling capacitive structure C(NM1 ) is electrically connected between the first tunable RF filter path 66 and the second tunable RF filter path 68 to define a first additional tunable RF filter path between the input terminal INi and the output terminal OUT 2 .
  • the first additional tunable RF filter path is thus provided by a portion of the first tunable RF filter path 66 and a portion of the second tunable RF filter path 68.
  • the first additional tunable RF filter path includes the resonator R(1 ,1 ) and the resonator R(2,2).
  • the first additional tunable RF filter path also includes the cross-coupling capacitive structure C(NM1 ) that is electrically connected between the resonator R(1 ,1 ) and the resonator R(1 ,2).
  • a second additional tunable RF filter path, a third additional tunable RF filter path, a fourth additional tunable RF filter path, and a fifth additional tunable RF filter path are also defined from the input terminal IN to the output terminal OUT 2 .
  • the second additional tunable RF filter path includes the resonator R(1 ,1 ), the cross-coupling capacitive structure C(PM1 ), the resonator R(1 ,2), the cross-coupling capacitive C(PM2), and the resonator R(2,2).
  • the third additional tunable RF filter path includes the resonator R(1 ,1 ), the cross-coupling capacitive structure C(PM3), the resonator R(2,1 ), the cross-coupling capacitive C(PM4), and the resonator R(2,2).
  • the fourth additional tunable RF filter path includes the resonator R(1 ,1 ), the cross-coupling capacitive structure C(PM1 ), the resonator R(1 ,2), the cross-coupling capacitive C(NM2), the resonator R(2,1 ), the cross-coupling capacitive structure C(PM4), and the resonator R(2,2).
  • the fifth additional tunable RF filter path includes the resonator R(1 ,1 ), the cross-coupling capacitive structure C(PM3), the resonator R(2,1 ), the cross-coupling capacitive C(NM2), the resonator R(1 ,2), the cross-coupling capacitive structure C(PM2), and the resonator R(2,2).
  • the first RF filter structure 60 shown in Figure 29 would be provided as an embodiment of the first RF filter structure 60 shown in Figure 28B.
  • the second tunable RF filter path 68 still provides a path between the input terminal IN 2 and the output terminal OUT 2 .
  • the first additional tunable RF filter path, the second additional tunable RF filter path, the third additional tunable RF filter path, the fourth additional tunable RF filter path, and the fifth additional tunable RF filter path would provide the paths from the input terminal IN to the output terminal OUT 2 .
  • the first RF filter structure 60 shown in Figure 29 would be provided as an embodiment of the first RF filter structure 60 shown in Figure 28C.
  • the second tunable RF filter path 68 still provides a path between the input terminal IN 2 and the output terminal OUT 2 .
  • the first additional tunable RF filter path, the second additional tunable RF filter path, the third additional tunable RF filter path, the fourth additional tunable RF filter path, and the fifth additional tunable RF filter path would provide the paths from the input terminal I N1 to the output terminal OUT 2 .
  • This may constitute a SISO filter implemented with an array to allow for a large number of signal paths and thus create one or more notches in the transfer function.
  • the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), R(2,2) shown in Figure 29 the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), R(2,2) may each be single- ended resonators, differential resonators, or different combinations of single- ended resonators and differential resonators.
  • the resonator R(1 ,1 ) and the resonator R(1 ,2) in the first tunable RF filter path 66 may each be provided in accordance with any of the embodiments of the resonator R(1 ,1 ) and the resonator R(1 ,2) described above with respect to Figures 22-27.
  • the resonator R(1 ,1 ) may include the inductor 208 (see Figure 24) and the capacitive structure 210 (see Figure 24).
  • the resonator R(1 ,2) may include the inductor 212 and the capacitive structure 214 (see Figure 24).
  • the resonator R(2,1 ) may include an inductor (like the inductor 208 in Figure 24) and a capacitive structure (like the capacitive structure 210 shown in Figure 24).
  • the resonator R(2,2) may include an inductor (like the inductor 212 in Figure 24) and a capacitive structure (like the capacitive structure 214 shown in Figure 24).
  • one or more of the resonators R(1 ,1 ), R(1 ,2) in the first tunable RF filter path 66 and one or more of the resonators R(2,1 ), R(2,2) in the second tunable RF filter path 68 may be weakly coupled.
  • the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), R(2,2) may be operably associated with one another such that an energy transfer factor between each of the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), R(2,2) is less than 10%.
  • the energy transfer factor between only a subset of the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), R(2,2) is less than 10%.
  • not all of the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), R(2,2) are weakly coupled to one another.
  • the inductor 208 (see Figure 24) of the resonator R(1 ,1 ), the inductor 212 (see Figure 24) of the resonator R(1 ,2), the inductor of the resonator R(2,1 ), and the inductor of the resonator R(2,2) may all be weakly coupled to one another.
  • displacements between the inductor 208 (see Figure 24) of the resonator R(1 ,1 ), the inductor 212 (see Figure 24) of the resonator R(1 ,2), the inductor of the resonator R(2,1 ), and the inductor of the resonator R(2,2) may all be less than or equal to half the maximum lateral width of the inductor 212.
  • only a proper subset of the inductor 208 (see Figure 24) of the resonator R(1 ,1 ), the inductor 212 (see Figure 24) of the resonator R(1 ,2), the inductor of the resonator R(2,1 ), and the inductor of the resonator R(2,2) may have displacements that are less than or equal to half the maximum lateral width of the inductor 212.
  • Figure 30 illustrates yet another embodiment of the first RF filter structure 60.
  • the first RF filter structure 60 includes the resonators R described above with respect to Figure 21 .
  • the resonators R of the first RF filter structure 60 shown in Figure 30 are arranged as a two-dimensional matrix of the
  • the first RF filter structure 60 includes an embodiment of the first tunable RF filter path 66, an embodiment of the second tunable RF filter path 68, an embodiment of the third tunable RF filter path 1 10, and an embodiment of the fourth tunable RF filter path 1 12.
  • the integer M for the first RF filter structure 60 shown in Figure 30 is four (4) or greater.
  • the integer N for the first RF filter structure 60 shown in Figure 30 is 3 or greater.
  • the integer M may be two (2) or greater and the integer N may be two(2) or greater. It should be noted that in alternative embodiments the number of resonators R in each row and column may be the same or different.
  • the first tunable RF filter path 66 includes the resonator R(1 ,1 ), the resonator R(1 ,2), and one or more additional resonators R, such as the resonator R(1 ,N), since the integer N is 3 or greater. All of the weakly coupled resonators R(1 ,1 ) through R(1 ,N) are weakly coupled to one another. Furthermore, the first tunable RF filter path 66 is electrically connected between a terminal TU1 and a terminal TANT1 .
  • the second tunable RF filter path 68 includes the resonator R(2,1 ), the resonator R(2,2), and one or more additional resonators R, such as the resonator R(2,N), since the integer N is 3 or greater. All of the weakly coupled resonators R(2,1 ) through R(2,N) are weakly coupled to one another. Furthermore, the second tunable RF filter path 68 is electrically connected between a terminal TU2 and a terminal TANT2.
  • the third tunable RF filter path 1 10 includes a resonator R(3,1 ), a resonator R(3,2), and one or more additional resonators R, such as a resonator R(3,N), since the integer N is 3 or greater. All of the weakly coupled resonators R(3,1 ) through R(3,N) are weakly coupled to one another. Alternatively, only a proper subset of them may be weakly coupled to one another. Furthermore, the third tunable RF filter path 1 10 is electrically connected between a terminal TU3 and a terminal TANT3.
  • the fourth tunable RF filter path 1 12 includes the resonator R(M,1 ), the resonator R(M,2), and one or more additional resonators R, such as the resonator R(M,N), since the integer N is 3 or greater. All of the weakly coupled resonators R(M,1 ) through R(M,N) are weakly coupled to one another. Alternatively, only a proper subset of them may be weakly coupled to one another. Furthermore, the fourth tunable RF filter path 1 12 is electrically connected between a terminal TU4 and a terminal TANT4.
  • the first tunable RF filter path 66 is configured to receive RF signals and output filtered RF signals.
  • the first RF filter structure 60 may include any number of tunable RF filter paths, such as, for example, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the fifth tunable RF filter path 122, and the sixth tunable RF filter path 124, described above with respect to Figures 1 1 -14.
  • Each of the resonators R may be a tunable resonator, which allows for a resonant frequency of each of the resonators to be varied to along a frequency range. In alternative embodiments, only a proper subset of the resonators R may be tunable. In still another embodiment, all of the resonators R are not tunable, but rather have a fixed transfer function.
  • all of the resonators R in the first RF filter structure 60 shown in Figure 30 are weakly coupled to one another.
  • the resonators R may all be operably associated with one another such that energy transfer factors between the resonators R are less than 10%.
  • the energy transfer factor is less than 10% only among a proper subset of the resonators R.
  • only the resonators R in adjacent tunable RF filter paths 66, 68, 1 10, 1 12 are weakly coupled to one another.
  • all the resonators R(1 ,1 ) through R(1 ,N) may be weakly coupled to all the resonators R(2,1 ) through R(2,N).
  • only subsets of adjacent resonators R may be weakly coupled to each other.
  • the resonators R(1 ,1 ), R(1 ,2) may be weakly coupled to the resonators R(2,1 ), R(2,2), while the resonators R(3,1 ), R(3,2) may be weakly coupled to the resonators R(M,1 ), R(M,2).
  • Sets S(1 ), S(2), S(3), S(4), S(5), and S(6) of cross-coupled capacitive structures are electrically connected between the resonators R.
  • Each of the sets S(1 ), S(2), S(3), S(4), S(5), and S(6) is arranged like the set S of cross-coupled capacitive structures described above with respect to Figure 29.
  • the set S(1 ) of cross-coupled capacitive structures is electrically connected between the resonators R(1 ,1 ), R(1 ,2) in the first tunable RF filter path 66 and the resonators R(2,1 ), R(2,2) in the second tunable RF filter path 68.
  • the set S(2) of cross- coupled capacitive structures is electrically connected between the resonators R(1 ,2), R(1 ,N) in the first tunable RF filter path 66 and the resonators R(2,2), R(2,N) in the second tunable RF filter path 68.
  • the set S(3) of cross-coupled capacitive structures is electrically connected between the resonators R(2,1 ), R(2,2) in the second tunable RF filter path 68 and the resonators R(3,1 ), R(3,2) in the third tunable RF filter path 1 10.
  • the set S(4) of cross-coupled capacitive structures is electrically connected between the resonators R(2,2), R(2,N) in the second tunable RF filter path 68 and the resonators R(3,2), R(3,N) in the third tunable RF filter path 1 10.
  • the set S(5) of cross-coupled capacitive structures is electrically connected between the resonators R(3,1 ), R(3,2) in the third tunable RF filter path 1 10 and the resonators R(M,1 ), R(M,2) in the fourth tunable RF filter path 1 12.
  • the set S(6) of cross-coupled capacitive structures is electrically connected between the resonators R(3,2), R(3,N) in the third tunable RF filter path 1 10 and the resonators R(M,2), R(M,N) in the fourth tunable RF filter path 1 12.
  • cross-coupled capacitive structures in the sets S(1 ), S(2), S(3), S(4), S(5), and S(6) of cross-coupled capacitive structures for the resonators R in adjacent columns or in adjacent ones of the tunable RF filter paths 66, 68, 1 10, 1 12 overlap. This is because in the matrix of the resonators R, each of the resonators R is adjacent to multiple other ones of the resonators R.
  • the sets S(1 ), S(2), S(3), S(4), S(5), and S(6) of cross-coupled capacitive structures may be connected between non-adjacent resonators R. For example, there may be cross-coupled capacitive structures between resonators R that are more than one column or row apart.
  • Figure 31 illustrates the embodiment of the first RF filter structure 60 shown in Figure 30 electrically connected to the first RF antenna 16, the second RF antenna 32, a third RF antenna 246, and a fourth RF antenna 247. More specifically, the first tunable RF filter path 66 is electrically connected to the first RF antenna 16 at the terminal TANT1 . The second tunable RF filter path 68 is electrically connected to the second RF antenna 32 at the terminal TANT2. The third tunable RF filter path 1 10 is electrically connected to the third RF antenna 246 at the terminal TANT3. The fourth tunable RF filter path 1 12 is electrically connected to the fourth RF antenna 247 at the terminal TANT4.
  • the first RF filter structure 60 shown in Figure 31 forms an interconnected two- dimensional matrix of the resonators R.
  • the sets S(1 ), S(2), S(3), S(4), S(5), and S(6) of cross-coupled capacitive structures provide a multitude of additional tunable RF filter paths between the terminals TU1 , TU2, TU3, TU4 and the terminals TANT1 , TANT2, TANT3, TANT4.
  • the terminals TANT1 , TANT2, TANT3, TANT4 may not be connected to antennas. Some antennas may be omitted depending on the functionality being realized.
  • the first RF filter structure 60 shown in Figure 31 can be tuned so that any combination of the resonators R is selectable for the propagation of RF signals. More specifically, the first RF filter structure 60 shown in Figure 31 is tunable to route RF receive signals from any combination of the terminals TANT1 , TANT2, TANT3, TANT4 to any combination of the terminals TU1 , TU2, TU3, TU4.
  • the first RF filter structure 60 shown in Figure 31 is tunable to route RF transmission signals from any combination of the terminals TU1 , TU2, TU3, TU4 to the terminals TANT1 , TANT2, TANT3, TANT4. Accordingly, the first RF filter structure 60 can be configured to implement various MIMO, SIMO, MISO, and SISO operations.
  • Figure 32 illustrates the first RF filter structure 60 shown in Figures 30 and 31 with examples of additional tunable RF filter paths 248, 250 highlighted. It should be noted, however, that there are a vast number of additional combinations of the resonators R that may be selected to provide tunable RF filter paths (e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the additional tunable RF filter path 248, and the additional tunable RF filter path 250) between the terminals TU1 , TU2, TU3, TU4 and the terminals TANT1 , TANT2, TANT3, TANT4.
  • tunable RF filter paths e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the additional tunable RF filter path 248,
  • the additional tunable RF filter paths 248, 250 may be used during MIMO, SIMO, MISO, and SISO operations. More specifically, the additional tunable RF filter path 248 connects the terminal TANT1 to the terminal TU2. The additional tunable RF filter path 250 connects the terminal TANT3 to the terminal TU2. As such, the first RF filter structure 60 may be tuned so that the additional tunable RF filter path 248 and the additional tunable RF filter path 250 are selected in a MISO operation from the terminal TANT1 and the terminal TANT3 to the terminal TU2. The additional tunable RF filter paths 248, 250 may also be used in SIMO operations.
  • the first RF filter structure 60 may be tuned so that the first tunable RF filter path 66 and the additional tunable RF filter path 248 are selected in a SIMO operation from the terminal TU2 to the terminal TANT1 .
  • the additional tunable RF filter paths 248, 250 can also be used in SISO operations from the terminal TANT1 to the terminal TU2 or from the terminal TANT3 to the terminal TU2.
  • the additional tunable RF filter paths 248, 250 may also be used in SIMO operations.
  • the first RF filter structure 60 may be tuned so that the first tunable RF filter path 66 and the additional tunable RF filter path 250 are selected in a SIMO operation from the terminal TANT1 to the terminal TU1 and from the terminal TANT3 to the terminal TU2.
  • MISO and SIMO operations can be used in conjunction with wideband antenna cables or fiber for transmitting RF signals in multiple RF communication frequency bands.
  • Specific communication frequency bands can be processed by certain dedicated RF filtering paths in the first RF filter structure 60.
  • different RF signals may be injected from a wideband antenna and then propagated along different dedicated tunable RF filter paths in the first RF filter structure 60 to the terminals TU1 , TU2, TU3, TU4.
  • These dedicated tunable RF filter paths can be configured to have a transfer function that is specifically designed to handle these RF signals.
  • the first RF filter structure 60 shown in Figures 30-32 is configured to tune a transfer function of any of the specific tunable RF filter paths (e.g., the first tunable RF filter path 66, the second tunable RF filter path 68, the third tunable RF filter path 1 10, the fourth tunable RF filter path 1 12, the additional tunable RF filter path 248, and the additional tunable RF filter path 250) in the first RF filter structure 60 by tuning resonators R that are not in the specific tunable RF filter path being used to route RF signals.
  • This can help reduce out-of-band noise and reduce insertion losses. It can also improve isolation and out-of-band attenuation.
  • Figure 33 illustrates yet another embodiment of the first RF filter structure 60.
  • the first RF filter structure 60 includes the resonators R and is arranged as a two-dimensional matrix of the resonators R, where N is equal to four (4) and M is equal to three (3).
  • the first RF filter structure 60 includes an embodiment of the first tunable RF filter path 66, an embodiment of the second tunable RF filter path 68, and an embodiment of the third tunable RF filter path 1 10. It should be noted that in alternative
  • the number of resonators R in each row and column may be the same or different.
  • the first tunable RF filter path 66 includes the resonator R(1 ,1 ), the resonator R(1 ,2), the resonator R(1 ,3), and the resonator R(1 ,4). Furthermore, the first tunable RF filter path 66 is electrically connected between the terminal TU1 and the terminal TANT1 . With regard to the second tunable RF filter path 68, the second tunable RF filter path 68 includes the resonator R(2,1 ), the resonator R(2,2), a resonator R(2,3), and a resonator R(2,4).
  • the second tunable RF filter path 68 is electrically connected between the terminal TU2 and the terminal TANT2.
  • the third tunable RF filter path 1 10 includes the resonator R(3,1 ), the resonator R(3,2), a resonator R(3,3), and a resonator R(3,4).
  • the third tunable RF filter path 1 10 is electrically connected between the terminal TU3 and the terminal TANT3.
  • the resonators R in a subset 252 of the resonators R(1 ,1 ), R(1 ,2) in the first tunable RF filter path 66 are weakly coupled to one another.
  • a cross-coupling capacitive structure CS1 is electrically connected between the resonators R(1 ,1 ), R(1 ,2).
  • the cross-coupling capacitive structure CS1 is a variable cross-coupling capacitive structure configured to vary a variable electric coupling coefficient between the resonators R(1 ,1 ), R(1 ,2).
  • a subset 254 of the resonators R(1 ,3), and R(1 ,4) in the second tunable RF filter path 68 is also weakly coupled to each other.
  • a cross-coupling capacitive structure CS2 is electrically connected between the resonators R(1 ,3), R(1 ,4).
  • the cross-coupling capacitive structure CS2 is a variable cross-coupling capacitive structure configured to vary a variable electric coupling coefficient between the resonators R(1 ,3), R(1 ,4).
  • a unidirectional coupling stage 256 is electrically connected within the first tunable RF filter path 66.
  • the unidirectional coupling stage 256 defines an amplifier gain and is configured to provide amplification within the first tunable RF filter path 66 in accordance with the amplifier gain.
  • the amplifier gain of the unidirectional coupling stage 256 is a variable amplifier gain.
  • the unidirectional coupling stage 256 is electrically connected between the resonator R(1 ,2) and the resonator R(1 ,3).
  • the variable amplifier gain can thus control a variable electric coupling coefficient between the resonator R(1 ,2) in the subset 252 and the resonator R(1 ,3) in the subset 254.
  • the unidirectional coupling stage 256 is an active semiconductor component, the unidirectional coupling stage 256 is unidirectional and thus only allows signal propagations from an input terminal IA of the unidirectional coupling stage 256 to an output terminal OA of the unidirectional coupling stage 256.
  • the resonator R(1 ,2) in the subset 252 is unidirectionally mutual electrically coupled to the resonator R(1 ,3) in the subset 254.
  • the resonators R(1 ,3), R(1 ,4) in the subset 254 are not electrically connected to the second tunable RF filter path 68 and the third tunable RF filter path 1 10.
  • the unidirectional coupling stage 256 thus results in a portion of the first tunable RF filter path 66 with the subset 254 of the resonators R(1 ,3), R(1 ,4) to be unidirectional. Consequently, signal flow can be to the terminal TANT1 but not from the terminal TANT1 .
  • variable amplifier gain (and thus the variable electric coupling coefficient between the resonator R(1 ,2) and the resonator R(1 ,3)) may be controlled using feed-forward control techniques and/or feedback control techniques.
  • the resonators R in a subset 258 of the resonators R(2,1 ), R(2,2), R(3,1 ), and R(3,2) in the second tunable RF filter path 68 and in the third tunable RF filter path 1 10 are weakly coupled to one another.
  • An unidirectional coupling stage 260 is electrically connected between the first tunable RF filter path 66 and the second tunable RF filter path 68. More specifically, the unidirectional coupling stage 260 is electrically connected between the resonator R(1 ,1 ) and the resonator R(2,1 ).
  • the unidirectional coupling stage 260 defines an amplifier gain and is configured to provide amplification in accordance with the amplifier gain.
  • the amplifier gain of the unidirectional coupling stage 260 is a variable amplifier gain.
  • the variable amplifier gain thus can control a variable electric coupling coefficient between the resonator R(1 ,1 ) in the subset 252 and the resonator R(2,1 ) in the subset 258.
  • a cross-coupling capacitive structure CS3 is electrically connected between the resonator R(1 ,2) and the resonator R(2,2).
  • the cross-coupling capacitive structure CS3 is a variable cross-coupling capacitive structure configured to vary a variable electric coupling coefficient between the resonators R(1 ,2), R(2,2).
  • a set S(A) of cross-coupling capacitive structures is electrically connected between the resonators R(2,1 ), R(2,2), R(3,1 ), and R(3,2) in the subset 258.
  • the set S(A) of cross-coupling capacitive structures is arranged like the set S of cross-coupling capacitive structures described above with respect to Figure 29.
  • the resonators R in a subset 262 of the resonators R(2,3), R(2,4), R(3,3), and R(3,4) in the second tunable RF filter path 68 and in the third tunable RF filter path 1 10 are weakly coupled to one another.
  • a set S(B) of cross-coupling capacitive structures is electrically connected between the resonators R(2,3), R(2,4), R(3,3), and R(3,4) in the subset 262.
  • the set S(B) of cross-coupling capacitive structures is arranged like the set S of cross-coupling capacitive structures described above with respect to Figure 29.
  • the first RF filter structure 60 shown in Figure 33 includes a cross-coupling capacitive structure CS4 and a unidirectional coupling stage 264.
  • the cross-coupling capacitive structure CS4 is electrically connected between the resonators R(2,2), R(2,3).
  • the cross-coupling capacitive structure CS4 is a variable cross-coupling capacitive structure configured to vary a variable electric coupling coefficient between the resonators R(2,2), R(2,3).
  • the unidirectional coupling stage 264 is electrically connected within the third tunable RF filter path 1 10.
  • the unidirectional coupling stage 264 is electrically connected between the resonator R(3,3) and the resonator R(3,2).
  • the unidirectional coupling stage 264 defines an amplifier gain and is configured to provide amplification within the third tunable RF filter path 1 10 in accordance with the amplifier gain.
  • the amplifier gain of the unidirectional coupling stage 264 is a variable amplifier gain. The variable amplifier gain can thus control a variable electric coupling coefficient between the resonator R(3,3) in the subset 262 and the resonator R(3,2) in the subset 258.
  • the unidirectional coupling stage 264 is an active semiconductor component, the unidirectional coupling stage 264 is unidirectional and thus only allows signal propagations from an input terminal IB of the unidirectional coupling stage 264 to an output terminal OB of the unidirectional coupling stage 264.
  • the resonator R(3,3) in the subset 262 is unidirectionally mutual electrically coupled to the resonator R(3,2) in the subset 258. Consequently, the third tunable RF filter path 1 10 shown in Figure 33 is unidirectional if the signal flow is between the terminal TANT3 and the terminal TU3 though the third tunable RF filter path 1 10.
  • an additional tunable RF signal path e.g., the additional RF terminal tunable RF signal path that includes the resonators R(3,1 ), R(2,2), R(2,3) and R(3,4)
  • R(3,1 ), R(2,2), R(2,3) and R(3,4) can be tuned to provide bidirectional signal flow between the terminal TU3 and the terminal TANT3 through the cross-coupling capacitive structure CS4.
  • the unidirectional coupling stages 256, 260, 264 may be active devices, such as amplifiers, diodes, transistors, networks of transistors, buffer stages, attenuation stages, and the like.
  • the unidirectional coupling stages 256, 260, 264 can have gains higher than one (1 ), lower than one (1 ), or equal to one (1 ).
  • the unidirectional coupling stages 256, 260, 264 may be passive devices.
  • the unidirectional coupling stages 256, 260, 264 may not be entirely or ideally unilateral, but may have some finite reverse coupling. In this case, the
  • unidirectional coupling stages 256, 260, 264 may be predominately unilateral.
  • the unidirectional coupling stages 256, 260, 264 may be used for multi-resonator applications and may improve isolation between certain parts, such as transmission ports and receive ports of a duplexer.
  • Figure 34 illustrates yet another embodiment of the first RF filter structure 60.
  • the first RF filter structure 60 shown in Figure 34 is integrated into an IC package 266.
  • the first RF filter structure 60 shown in Figure 34 includes the resonators R and is arranged as a two-dimensional matrix of the resonators R, where N is equal to three (3) and M is equal to two (2). It should be noted that in alternative embodiments the number of resonators R in each row and column may be the same or different.
  • the first RF filter structure 60 includes an embodiment of the first tunable RF filter path 66 and an embodiment of the second tunable RF filter path 68.
  • the first tunable RF filter path 66 includes the resonator R(1 ,1 ), the resonator R(1 ,2), and the resonator R(1 ,3).
  • the second tunable RF filter path 68 includes the resonator R(2,1 ), the resonator R(2,2), and the resonator R(2,3).
  • a set S(X) of cross-coupling capacitive structures is electrically connected between the resonators R(1 ,1 ), R(1 ,2), R(2,1 ), and R(2,2).
  • the set S(X) of cross-coupling capacitive structures is arranged like the set S of cross-coupling capacitive structures described above with respect to Figure 29.
  • a set S(Y) of cross-coupling capacitive structures is electrically connected between the resonators R(1 ,2), R(1 ,3), R(2,2), and R(2,3).
  • the set S(Y) of cross-coupling capacitive structures is also arranged like the set S of cross- coupling capacitive structures described above with respect to Figure 29.
  • the IC package 266 houses a package substrate 268, a semiconductor die 270, and a semiconductor die 272.
  • the semiconductor die 270 and the semiconductor die 272 are mounted on the package substrate 268.
  • the resonators R of the first RF filter structure 60 are formed by the package substrate 268.
  • the set S(X) of cross- coupling capacitive structures is formed by the semiconductor die 270.
  • the set S(Y) of cross-coupling capacitive structures is formed by the semiconductor die 272.
  • the set S(X) of cross-coupling capacitive structures and the set S(Y) of cross-coupling capacitive structures are formed on multiple and separate semiconductor dies 270, 272. Using the multiple and separate semiconductor dies 270, 272 may be helpful in order to increase isolation.
  • the multiple and separate semiconductor dies 270, 272 may have less area than the semiconductor die 268 shown in Figure 34. As such, the embodiment shown in Figure 35 may consume less die area.
  • Figure 35 illustrates another embodiment of an IC package 266' that houses the same embodiment of the first RF filter structure 60 described above with regard to Figure 34.
  • the IC package 266' is the same as the IC package 266 shown in Figure 34, except that the IC package 266' only has a single semiconductor die 274.
  • both the set S(X) of cross-coupling capacitive structures and the set S(Y) of cross-coupling capacitive structures are formed by the semiconductor die 272.
  • the IC package 266' allows for a more compact arrangement than the IC package 266.
  • Figure 36 illustrates yet another embodiment of the first RF filter structure 60.
  • the first RF filter structure 60 is arranged as a three-dimensional matrix of resonators R1 , R2, R3. More specifically, a two- dimensional matrix of the resonators R1 is provided on a plane k, a two- dimensional array of the resonators R2 is provided on a plane m, and a two- dimensional array of the resonators R3 is provided on a plane n.
  • Cross-coupling capacitive structures CC are electrically connected between the resonators R1 , R2, R3 that are adjacent to one another in the same plane k,m,n and in the different planes k,m,n.
  • the three-dimensional matrix of resonators R1 , R2, R3 thus allows for more resonators to be cross-coupled to one another. This allows for the first RF filter structure 60 to provide greater numbers of tunable RF filter paths and allows for the first RF filter structure 60 to be tuned more accurately.
  • resonators R1 , R2, R3 in each of the planes k, n, m may be different or the same.
  • the three-dimensional matrix of resonators can be used in MIMO, SIMO, MISO, and SISO applications.

Landscapes

  • Transceivers (AREA)

Abstract

L'invention concerne des structures de filtre RF pouvant comporter plusieurs voies de filtrage, et comprenant des résonateurs faiblement couplés. Les voies de filtrage peuvent être interconnectées de façon à ce que des voies de filtrage additionnelles puissent être réalisées entre des bornes d'entrée et de sortie des structures de filtre RF. Les résonateurs faiblement couplés depuis les voies de filtrage peuvent être agencés en matrice. Dans un mode de réalisation, une structure de filtre RF comprend une première voie de filtrage et une seconde voie de filtrage. La première voie de filtrage comprend (au moins) une première paire de résonateurs faiblement couplés tandis qu'une seconde voie de filtrage comprend (au moins) une seconde paire de résonateurs faiblement couplés. Pour interconnecter la première voie de filtrage et la seconde voie de filtrage, une structure capacitive à couplage croisé est connectée électriquement entre la première voie de filtrage et la seconde voie de filtrage. Ainsi, une voie de filtrage additionnelle peut être réalisée via l'interconnexion fournie par la structure capacitive à couplage croisé.
PCT/US2014/048608 2013-08-01 2014-07-29 Structure de filtre rf accordable présentant des résonateurs couplés WO2015017406A1 (fr)

Applications Claiming Priority (20)

Application Number Priority Date Filing Date Title
US201361860932P 2013-08-01 2013-08-01
US61/860,932 2013-08-01
US201361909028P 2013-11-26 2013-11-26
US61/909,028 2013-11-26
US201461938884P 2014-02-12 2014-02-12
US61/938,884 2014-02-12
US201461949581P 2014-03-07 2014-03-07
US61/949,581 2014-03-07
US201461951844P 2014-03-12 2014-03-12
US61/951,844 2014-03-12
US201461982946P 2014-04-23 2014-04-23
US201461982971P 2014-04-23 2014-04-23
US201461982952P 2014-04-23 2014-04-23
US61/982,952 2014-04-23
US61/982,946 2014-04-23
US61/982,971 2014-04-23
US201462008192P 2014-06-05 2014-06-05
US62/008,192 2014-06-05
US14/298,829 2014-06-06
US14/298,829 US9455680B2 (en) 2013-06-06 2014-06-06 Tunable RF filter structure formed by a matrix of weakly coupled resonators

Publications (1)

Publication Number Publication Date
WO2015017406A1 true WO2015017406A1 (fr) 2015-02-05

Family

ID=52432376

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2014/048608 WO2015017406A1 (fr) 2013-08-01 2014-07-29 Structure de filtre rf accordable présentant des résonateurs couplés

Country Status (1)

Country Link
WO (1) WO2015017406A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107710629A (zh) * 2015-07-06 2018-02-16 株式会社村田制作所 高频模块
CN108370258A (zh) * 2015-09-10 2018-08-03 蓝色多瑙河系统有限公司 校准串行互连
CN109167605A (zh) * 2018-11-13 2019-01-08 深圳飞骧科技有限公司 射频前端架构及移动终端

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5841330A (en) * 1995-03-23 1998-11-24 Bartley Machines & Manufacturing Series coupled filters where the first filter is a dielectric resonator filter with cross-coupling
US5896073A (en) * 1996-02-20 1999-04-20 Mitsubishi Denki Kabushiki Kaisha High frequency filter having a plurality of serially coupled first resonators and a second resonator
US6529750B1 (en) * 1998-04-03 2003-03-04 Conductus, Inc. Microstrip filter cross-coupling control apparatus and method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5841330A (en) * 1995-03-23 1998-11-24 Bartley Machines & Manufacturing Series coupled filters where the first filter is a dielectric resonator filter with cross-coupling
US5896073A (en) * 1996-02-20 1999-04-20 Mitsubishi Denki Kabushiki Kaisha High frequency filter having a plurality of serially coupled first resonators and a second resonator
US6529750B1 (en) * 1998-04-03 2003-03-04 Conductus, Inc. Microstrip filter cross-coupling control apparatus and method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107710629A (zh) * 2015-07-06 2018-02-16 株式会社村田制作所 高频模块
US10396749B2 (en) 2015-07-06 2019-08-27 Murata Manufacturing Co., Ltd. Radio-frequency module
CN108370258A (zh) * 2015-09-10 2018-08-03 蓝色多瑙河系统有限公司 校准串行互连
CN109167605A (zh) * 2018-11-13 2019-01-08 深圳飞骧科技有限公司 射频前端架构及移动终端

Similar Documents

Publication Publication Date Title
US9455680B2 (en) Tunable RF filter structure formed by a matrix of weakly coupled resonators
US10965258B2 (en) Weakly coupled tunable RF receiver architecture
US9825656B2 (en) Weakly coupled tunable RF transmitter architecture
US9685928B2 (en) Interference rejection RF filters
US9780756B2 (en) Calibration for a tunable RF filter structure
US11177064B2 (en) Advanced 3D inductor structures with confined magnetic field
US9444417B2 (en) Weakly coupled RF network based power amplifier architecture
US9628045B2 (en) Cooperative tunable RF filters
US9780817B2 (en) RX shunt switching element-based RF front-end circuit
US9755671B2 (en) VSWR detector for a tunable filter structure
US9774311B2 (en) Filtering characteristic adjustments of weakly coupled tunable RF filters
US20150092625A1 (en) Hybrid active and passive tunable rf filters
US9966981B2 (en) Passive acoustic resonator based RF receiver
US9705542B2 (en) Reconfigurable RF filter
US9800282B2 (en) Passive voltage-gain network
US20170040966A1 (en) Combined impedance matching and rf filter circuit
WO2015017406A1 (fr) Structure de filtre rf accordable présentant des résonateurs couplés
US20220076869A1 (en) Advanced 3d inductor structures with confined magnetic field

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14752506

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14752506

Country of ref document: EP

Kind code of ref document: A1