KR20110088444A - Resonator filter with multiple cross-couplings - Google Patents

Abstract

The filter device provides for filtering of the signal. The filter arrangement includes a plurality of series resonators, a plurality of shunt resonators, and a plurality of cross coupled circuits. The series resonator is connected in series between the antenna and one of the transmitter or the receiver. The shunt resonator is respectively connected between at least one series resistor and the ground voltage. The cross coupling circuit is configured to bypass at least two series resonators of the plurality of series resonators and at least one shunt resonator of the plurality of shunt resonators.

Description

Filter Units, Duplexers, and Half Weld Ladder Filters {RESONATOR FILTER WITH MULTIPLE CROSS-COUPLINGS}

The present invention relates to a filter device comprising a plurality of series resonators, a plurality of shunt resonators, and a plurality of cross coupled circuits.

Reference to Related Application

The present invention is a partial continuing application of US Patent Application No. 12 / 509,863, filed on July 27, 2009, filed with the US Patent and Trademark Department, the content of which is incorporated herein by reference.

Portable communication devices, such as mobile phones, personal digital assistants, electronic gaming devices, laptop computers, and the like, are configured to communicate over a wireless network. Thus, each such portable communication device typically relies on a transmitter and receiver (or transceiver) that are connected with a single or common antenna to transmit and receive data and control signals over a wireless network. To use a common antenna, you must include a duplexer that interfaces between the common antenna and the transmitter and the receiver, respectively, so that the transmitter can transmit the signal at the transmit frequency and the receiver can receive the signal at a different receive frequency. do. In general, a duplexer has two pass-pass filters that respectively prevent or reduce interference between the transmitted and received signals by having different passbands in filtering the transmitted and received signals. It includes.

Various types of wireless networks include universal mobile telecommunications system (UMTS), global system for mobile communication (GSM), personal communications services (PCS), digital cellular system (DCS), international mobile telecommunication (IMT), and enhanced data rates for EDGE. And according to different communication standards, such as GSM evolution). Communication standards distinguish separate bands for transmitting (uplink) and receiving (downlink) signals. For example, UMTS band 2 (PCS) provides an uplink frequency band of 1850 MHz-1910 MHz and a downlink frequency band of 1930 MHz-1990 MHz, and UMTS band 3 (DCS) provides an uplink frequency band of 1710 MHz-1785 MHz and 1805 MHz- Provides downlink frequency band of 1880 MHz, UMTS band 7 (IMT-E) provides uplink frequency band of 2500 MHz-2570 MHz and downlink frequency band of 2620 MHz-2690 MHz, UMTS band 8 (GMS-900) provides 880 MHz It provides an uplink frequency band of -915MHz and a downlink frequency band of 925MHz to 960MHz. Thus, a duplexer operating in accordance with the UMTS standard will include a transmit filter having a pass band in the corresponding uplink frequency band and a receive filter having a pass band in the corresponding downlink frequency band.

The demand for smaller, cheaper and more efficient portable communication devices is growing considerably. Therefore, portable communication devices, which not only reduce manufacturing costs and increase product yield, but also reduce size and weight, have an advantage. For example, the band pass filter of the duplexer in a portable communication device is smaller, consumes less power, and improves performance characteristics (such as low insertion loss and high out-of-band attenuation). There is a need to have it and to operate at higher frequencies. Such duplexers may include resonators for filtering the transmitted and received signals, such as thin film bulk acoustic resonators (FBARs). However, for example, it is difficult to design and manufacture due to the pass band and stop band conditions of the corresponding receive and transmit band pass filters, and the circuit matching conditions between the band pass filter and the antenna.

In an exemplary embodiment, the filter device for filtering the signal includes a plurality of series resonators, a plurality of shunt resonators, and a plurality of cross coupled circuits. The series resonator is connected in series between the antenna and either the transmitter or the receiver. The shunt resonator is respectively connected between at least one series resistor and the ground voltage. The cross coupling circuit is configured to bypass at least two series resonators of the plurality of series resonators and at least one shunt resonator of the plurality of shunt resonators.

In another exemplary embodiment, the duplexer for interfacing the receiver and the transmitter with a common antenna includes first and second filters. The first filter includes a plurality of first series resonators connected in series between one of the receivers or transmitters and the antenna, a plurality of first shunt resonators respectively connected between at least one first series resonator and ground voltage, And a first cross coupled circuit. The second filter includes a plurality of second series resonators connected in series between one of the transmitters or receivers and the antenna, a plurality of second shunt resonators respectively connected between at least one second series resistor and a ground voltage, And a second cross coupled circuit.

In another exemplary embodiment, a half-ladder filter having a pass band includes a plurality of series resonators, a plurality of shunt resonators, and a plurality of cross coupled circuits. The series resonator is connected in series between the input node and the output node. The shunt resonator is respectively connected between at least one series resistor and the ground voltage. The cross coupling circuit includes a corresponding capacitor, each cross coupling circuit bypassing at least one of the series resonators and at least one of the plurality of shunt resonators. The cross coupling circuit causes the transmission zero to shift to a higher frequency than the upper edge of the pass band of the filter.

Exemplary embodiments will be best understood by reading the following detailed description in conjunction with the accompanying drawings. Note that the various features are not necessarily drawn to scale. In fact, for clarity of explanation, the dimensions may be arbitrarily increased or decreased. Where appropriate and applicable, like reference numerals refer to like elements.

It provides a duplexer that is smaller, consumes less power, has improved performance characteristics, and has a band pass filter that operates at higher frequencies.

1 is a block diagram illustrating a duplexer with a resonator filter in accordance with a representative embodiment.
2 is a circuit diagram illustrating a duplexer with transmit and receive resonator filters in accordance with an exemplary embodiment.
3A is a signal diagram illustrating the simulated performance of a duplexer with a cross coupled device in accordance with an exemplary embodiment.
3B is a signal diagram illustrating the simulated performance of a duplexer without cross coupling elements.
4 is a circuit diagram illustrating a transmission resonator filter in accordance with an exemplary embodiment.
5 is a circuit diagram illustrating a transmission resonator filter in accordance with an exemplary embodiment.
6A and 6B are circuit diagrams illustrating a transmission resonator filter with nine resonators in accordance with an exemplary embodiment.
7 is a circuit diagram illustrating a receive resonator filter in accordance with an exemplary embodiment.
8 is a circuit diagram illustrating a receive resonator filter having a plurality of cross coupled inductors in accordance with an exemplary embodiment.
9A and 9B are circuit diagrams illustrating a receive resonator filter with nine resonators in accordance with a representative embodiment.
10A and 10B are circuit diagrams illustrating a transmission resonator filter with multiple cross coupling capacitors in accordance with an exemplary embodiment.
FIG. 11 is a circuit diagram illustrating a transmission resonator filter having a plurality of cross coupling capacitors according to an exemplary embodiment. FIG.

In the following detailed description, exemplary embodiments that are disclosed for specific details, for purposes of illustration and not for purposes of limitation, are presented to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that other embodiments in accordance with the present invention that depart from the specific details disclosed herein may fall within the scope of the appended claims and thereby provide the advantages of the present invention. Moreover, descriptions of well-known devices and methods may be omitted so as not to obscure the description of the exemplary embodiments. Such methods and apparatus are clearly within the scope of the present invention.

In general, it will be understood that the drawings and various components presented herein are not drawn to scale. Also, relative terms such as "top", "bottom", "top", "bottom", "top", and "bottom" are used to describe the relationship of the various elements to each other, as shown in the accompanying drawings. will be. It will be understood that these relative terms are intended to include other arrangements of devices and / or components in addition to the arrangements shown in the figures. For example, if the view direction of the drawing of the device is reversed, then a device described as being “up” of another device, for example, will now be below the other device.

1 is a block diagram illustrating a duplexer with a resonator bandpass filter in accordance with a representative embodiment.

Referring to FIG. 1, the duplexer 100 interfaces a receiver (not shown) and a transmitter (not shown) with a common antenna 110 to receive and transmit wireless communication signals. The wireless communication signal may be, for example, a radio frequency (RF) signal that conforms to various communication standards, examples of which are described above.

In the exemplary embodiment shown, the duplexer 100 includes a receive filter 120 that connects between the antenna 110 through a receiver terminal 130 and a receiver terminal 130, and a transmitter terminal 150. And a transmission filter 140 connecting between the antenna 110 via the transmitter and antenna terminals 115. The receive filter 120 is a band pass filter for downlinking the signal transmitted to the receiver through the antenna 110, and the transmit filter 140 uplinks the signal transmitted from the transmitter through the antenna 110. uplink) is a bandpass filter. The duplexer 100 may be included in any type of portable communication device, such as a cell phone, PDA, electronic gaming device, laptop computer, and the like.

FIG. 2 is a circuit diagram illustrating a duplexer with exemplary first and second resonator band pass filters in accordance with an exemplary embodiment as described with reference to FIG. 1.

More specifically, the duplexer 200 is shown to include a first filter, referred to as transmit filter 240 for convenience of description, and a second filter, referred to as receive filter 220 for convenience of description. Each of the first and second filters has a half-ladder shape. In various embodiments, the first and second filters may be, for example, a receive filter connected to a receiver, and the second filter may be, for example, a transmit filter connected to a transmitter, without departing from the scope of the present invention. It will be appreciated that the second filter may be inverted.

The transmit and receive filters 240, 220 are configured to have resonators 241-248 and resonators 221-228, respectively, according to the illustrated embodiment. However, other embodiments of the duplexer 200 may have other configurations of transmit and receive filters, for example, FIGS. 4, 5, 6a, 6b, 10a, 10b and 10, without departing from the scope of the present invention. A transmission filter as shown in 11 (each representing a representative embodiment of transmission filters 440, 540, 640a, 640b, 1040a, 1040b, 1140), and FIGS. 7, 8, 9a, and 9b. It will be appreciated that each may include a receive filter as shown in (each of which illustrates a representative embodiment of receive filters 720, 820, 920a, 920b). It will also be appreciated that other embodiments of the duplexer 200 may combine any representative embodiment of the transmit filter with any representative embodiment of the receive filter.

Referring to FIG. 2, receive filter 220 is a ladder filter with a plurality of series and shunt resonators 221-228 (described below). Each series and shunt resonator 221-228 may be a bulk acoustic wave (BAW) resonator such as, for example, a film bulk acoustic resonator (FBAR) or a solidly mounted resonator (SMR), and may be stacked between the upper and lower electrodes. It may include a thin film piezoelectric layer formed of a structure. The thin film piezoelectric layer may be formed of a material such as aluminum nitride (AlN), lead zirconate titanate (PZT), or another film suitable for semiconductor processing. In one embodiment, receive series and shunt resonators 221-228 are fabricated using a common layer of piezoelectric material. The upper and lower electrodes can be formed of any conductive metal suitable for semiconductor processes, such as molybdenum, tungsten, aluminum, and the like. Alternatively, each series and shunt resonator 221-228 may be a surface acoustic wave (SAW) resonator. In addition to being included in the duplexer, receive filter 220 may be used as a stand alone band pass filter or may be included in a multiplexer or other device. The receive filter 220 includes a series circuit including a phase shifter 231 and first to fourth series resonators 221-224 connected in series between the antenna terminal 115 and the receiver terminal 130. Phase shifter 231 is configured to provide phase shifting between 60 Hz and 120 Hz in accordance with the half-ladder filter characteristics of receive and transmit filters 220 and 240 in duplexer 200. In various embodiments, for example, the phase shifter 231 may be replaced with a shunt inductance matching circuit (not shown) when the downlink and uplink frequency bands have a difference of approximately 1% or more. Receive filter 220 also typically includes a shunt circuit including first to fourth shunt resonators 225-228 and corresponding first to fourth inductors 235-238, respectively, connected between the series circuit and the ground voltage. It is provided. In one embodiment, the series and shunt resonators 221-228 have the same coupling coefficient.

More specifically, in the exemplary embodiment shown, the first shunt resonator 225 is a single stage (eg, top electrode) connected between the phase shifter 231 and the first series resonator 221 at node 233. ) And an opposite end (eg, bottom electrode) connected to ground via an inductor 235. The second shunt resonator 226 has one end connected between the first and second series resonators 221, 222 and an opposite end connected to ground through an inductor 236. The third shunt resonator 227 has one stage connected between the second and third series resonators 222 and 223 and the opposite stage connected to the mutual inductance node 232 through the inductor 237. Similarly, the fourth shunt resonator 228 most closely connected to the receiver terminal 130 has one end connected between the third and fourth series resonators 223 and 224 and mutual inductance through the inductor 238. It has an opposite end connected to node 232. Mutual inductance node 232 is connected to ground through a mutual or common ground inductor 239 that is a cross coupled inductor. In various embodiments, common ground inductor 239 may be replaced with another mutual inductance between the current paths of adjacent shunt resonators of shunt resonators 225-228. Examples of other configurations are described below with reference to FIGS. 7, 8, 9A and 9B.

The transmit filter 240 is also a ladder filter and includes a plurality of series and shunt resonators 241-248 (described below). Each series and shunt resonator 241-248 may be an FBAR such as, for example, a thin film piezoelectric layer formed in a stacked structure between upper and lower electrodes. The thin film piezoelectric layer may be formed of a material such as aluminum nitride, PZT or other film material suitable for other semiconductor processes. In one embodiment, the series and shunt resonators 241-248 are fabricated using a common layer of piezoelectric material. Also in one embodiment, the series and shunt resonators 221-228 as well as the series and shunt resonators 241-248 of the receive filter 220 may be fabricated using a common layer of piezoelectric material. The upper and lower electrodes can be formed of any conductive metal suitable for semiconductor processes, such as molybdenum, tungsten, aluminum, and the like. In addition to being included within the duplexer, transmit filter 240 may be used as a standalone band pass filter or may be included within a multiplexer or other device.

The transmit filter 240 has a series circuit including first to fourth transmit filter series resonators 241-244 connected in series between the antenna terminal 115 and the transmitter terminal 150. Transmit filter 240 also typically includes a first to fourth shunt resonator 245-248 and a corresponding first to fourth inductor 255-258, respectively, connected between the series circuit and the ground voltage. A circuit is provided. In one embodiment, the series and shunt resonators 241-248 of the transmit filter 240 have the same coupling coefficient, which is also the coupling coefficient of the series and shunt resonators 221-228 of the receive filter 220. May or may not be equal to. The use of minimum coupling coefficients in series and shunt resonators 221-228 and / or series and shunt resonators 241-248 can reduce die size.

More specifically, in the exemplary embodiment shown, the first shunt resonator 245 includes one stage (eg, top electrode) connected between the first and second series resonators 241, 242, and the inductor 255. And an opposite end (e.g., lower electrode) connected to ground via < RTI ID = 0.0 > The second shunt resonator 246 has one end connected between the second and third series resonators 242 and 243 and an opposite end connected to ground through an inductor 256. The third shunt resonator 247 has one end connected between the third and fourth series resonators 243 and 244 and an opposite end connected to the capacitance node 251. Capacitance node 251 is connected to ground via inductor 257 and is connected to antenna terminal 115 via cross coupled capacitor 259. The fourth shunt resonator 248 most closely connected to the transmitter terminal 150 has one end connected between the fourth series resonator 244 and the transmitter terminal 150 and the opposite side connected to ground through the inductor 258. A stage is provided.

More generally speaking, in some embodiments cross coupled capacitor 259 is one of a first node connected to at least one series resonator 241-244 (eg, series resonator 241) and a shunt resonator ( And a second node connected to one of 245-248 (eg, shunt resonator 247). Between the first and second nodes are three series resonators (e.g., series resonators 241-243) and one shunt resonator (e.g., shunt resonators 247). The second node (eg, capacitance node 251) is separated from the ground voltage by an inductor (eg, inductor 257). Examples of other configurations are described below with reference to FIGS. 4, 5, 6A, 6B, 10A, 10B and 11.

In one embodiment, the common ground inductor 239 and / or inductors 235-238 of the receive filter 220 are fabricated on a common substrate with the receive series and shunt resonators 221-228, but the inductor may also be wired. It may be implemented as traces on an organic substrate or a ceramic substrate with or without bonds. Likewise, in one embodiment, cross coupling capacitor 259 and / or inductor 255-258 of transmit filter 240 are fabricated on a common substrate, such as transmit series and shunt resonators 241-248, but receive filter ( It may or may not be fabricated on a common substrate, such as 220. Inductors may also be implemented on organic or ceramic substrates with or without wirebonds. Also in one embodiment, the receive and transmit filters 220, 240 are integrally mounted in the same package.

The center frequencies of the pass bands for the receive filter 220 and the transmit filter 240 are offset relative to each other to reduce or prevent overlap of each pass band. The center frequency is selected within the downlink and uplink frequency bands of the applicable communication standards, respectively. For example, according to the GSM-900 standard, the usable frequency band of the receive filter 220 is 925 MHz-960 MHz, and the usable frequency band of the transmit filter 240 is 880 MHz-915 MHz. Therefore, for illustrative purposes only, it may be assumed that the passband center frequency of the receive filter 220 is approximately 943.3 MHz, and the passband center frequency of the transmit filter 240 is approximately 887.2 MHz. However, it will be understood that various embodiments may use other standards or include other center frequencies and / or passbands in accordance with the GSM-900 standard without departing from the scope of the present invention.

Referring again to FIG. 2, the common ground inductor 239 of the receive filter 220 is configured to reach the transmission zero of the received (downlink) signal to the middle of its stop band below the pass band of the receive filter 220. Shift down. The value of the common ground inductor 239 determines the extent to which the transmission zero can shift its frequency down from the pass band limit. For example, in one embodiment the value of the common ground inductor 239 is selected to a value that allows the transmit zero to be shifted to or near the center frequency of the pass band of the transmit filter 240.

Similarly, cross coupled capacitor 259 of transmit filter 240, along with third inductor 257, transmits the zero point of transmission of the transmitted (uplink) signal to its stop band above the pass band of transmit filter 240. Shift up to the middle of. The values of the cross coupling capacitor 259 and the third inductor 257 determine the extent to which the transmission zero shifts up from the upper passband upper limit on frequency. For example, in one embodiment the values of the cross coupling capacitor 259 and / or the third inductor 257 are selected such that the transmit zero is shifted to or near the center frequency of the pass band of the receive filter 220. . This frequency placement of the transmit zeros (and poles) of the receive and transmit filters 220, 240 achieves nearly ideal elliptic filter performance in the duplexer 200.

Those skilled in the art will appreciate that filter configurations (FIGS. 4 and 4 described below) in order to provide specific benefits for any particular situation or to meet specific design requirements for application to various implementations without departing from the scope of the present invention. It will be appreciated that (shown in FIG. 11) may be included in either the transmit filter or the receive filter. For example, in the exemplary embodiment shown in FIG. 2, for illustrative purposes, it is assumed that the passband center frequency of the downlink frequency band of the received signal is higher than the passband center frequency of the uplink frequency band of the transmitted signal. Hence, this capacitor is shown as part of the transmit filter 240 because cross coupled capacitor 259 shifts the transmission zero of the signal high (toward the downlink frequency band), and common ground inductor 239 represents the signal. This inductor is shown as part of the receive filter 220 because it shifts the transmission zero down (toward the uplink frequency band).

However, it will be appreciated that in various other embodiments and / or configurations, for example in conformity with 3GPP bands 13 and 14, the passband center frequency of the uplink frequency band may be higher than the passband center frequency of the downlink frequency band, In this case, a first filter having a configuration substantially the same as that of the transmission filter 240 is a reception filter connected between the receiver terminal 130 and the antenna terminal 115 to shift the transmission zero of the downlink signal to be higher. Can be. Similarly, the second filter having a configuration substantially the same as that of the receive filter 220 may be a transmit filter connected between the transmitter terminal 150 and the antenna terminal 115 to shift the transmission zero of the uplink signal to be lowered. have.

Further, according to various embodiments, the duplexer 200 does not require any inductor larger than the wirebond inductance outside the receive and transmit filters 220, 240, but is limited in area to reduce die cost. Filters with can be used as matching elements to enable better performance. For example, the maximum shunt resonator inductor is only about 0.7nH, but the typical duplexer uses a value of 3-4nH. Thus, the size of the duplexer 200 (and / or receive and transmit filters 220, 240) is smaller than the resonator filter of a conventional duplexer, and the out-of-band rejection and in-band insertion loss ( In-band insertion loss is further improved over resonator filters of conventional duplexers. In addition, since the performance variation caused by the external inductor can be eliminated, the configuration of the duplexer 200 will result in higher product yield.

FIG. 3A is a signal diagram illustrating simulated duplexer performance, in accordance with a representative embodiment, assuming a high quality coefficient resonator having a cross coupling element shifting the transmission zero within the frequency response for illustrative purposes. Representative frequency responses of filter 220 and transmit filter 240 are shown.

More specifically, FIG. 3A corresponds to the exemplary configuration of the duplexer 200 shown in FIG. 2, where the common ground inductor 239 has a value of approximately 0.76 nH, and the cross coupling capacitor 259 is approximately 0.53. has a value of pF. In addition, it is assumed that the center frequency of the pass band of the reception filter is approximately 943.3 MHz, and the center frequency of the pass band of the transmission filter 240 is approximately 887.2 MHz. The values of inductors 235-238 can be values between approximately 0.3 nH and 0.7 nH (typical wirebond values) and the values of inductors 255-258 are in the same range. Each resonator 221-228, 241-248 may be an FBAR having an area in the range of approximately 1000-100,000 μm ² , depending on the frequency and bandwidth conditions of the filter / duplexer and the optimum impedance for each particular resonator. Those skilled in the art may vary in size and / or values of resonators, inductors, and cross coupling capacitors in various embodiments to provide unique benefits for any particular situation or to meet specific design requirements for application to various implementations. I will understand.

Referring to FIG. 3A, curve 340 represents the frequency response of a transmission filter 240 according to an exemplary embodiment, which represents the forward transmission gain S ₂₁ (in dB) as a function of the transmitted signal frequency (in MHz). The passband of transmit filter 240 is approximately 870 MHz-920 MHz. Curve 320 represents the reverse response loss S ₂₃ (in dB) as a function of the received signal frequency (in MHz) as the frequency response of the receive filter 220. The pass band of the receive filter 220 is approximately 920 MHz-970 MHz. Curve 340 is approximately 943.3 MHz, with the transmission zero after the initial roll off of the in-band frequency response by operation of cross coupling capacitor 259 substantially coincident with the center frequency of receive filter 220. shifted to (indicated by m1). In the example shown, the out-of-band attenuation at m1 for transmit filter 240 is -106.852 dB. Similarly, curve 320 substantially coincides with the center frequency of transmit filter 220 after the zero point of transmission after initial roll-off of the in-band frequency response of receive filter 220 by operation of common ground inductor 239. Shows shifting to approximately 887.2 MHz (denoted m2). In the example shown, the out-of-band attenuation at m2 for receive filter 220 is -104.173 dB.

For comparison, FIG. 3B is a signal diagram illustrating simulated duplexer performance, having substantially the same configuration as receive and transmit filters 220, 240 as described above with reference to FIG. 3A, but for example transmitting Representative frequency responses of receive and transmit filters that do not include cross coupled elements, such as common ground inductor 239 and cross coupled capacitor 259, shifting zero to the center of rejection bands.

Curve 440 indicates that the transmission zero after the initial roll-off of the in-band frequency response occurs at approximately 928 MHz with the edge of the pass band of the receive filter 220. On the other hand, the frequency response (indicated by m1) of the transmit filter 240 at the center frequency of the receive filter 220 is significantly higher at out-of-band attenuation of -53.311 dB. Curve 420 indicates that the transmission zero after the initial roll-off of the in-band frequency response occurs at approximately 910 MHz with the edge of the pass band of the transmit filter 240. On the other hand, the frequency response (denoted in m2) of the receive filter 220 at the center frequency of the transmit filter 240 is significantly higher in out-of-band attenuation of -48.776 dB. Thus, the receive filter 220 and the transmit filter 240 each exhibit a large drop in the cancellation level at the passband frequencies of the other filters.

The placement of the transmission zero can be controlled by changing the values of each of the cross coupling capacitor 259 and the common ground inductor 239 to the corresponding center values, i.e., 0.53 pF and 0.76 nH, as shown in FIG. 3A. In other words, as the value of the cross coupling capacitor 259 approaches 0.53 pF, the transmission zero moves upward, and further, moves to the stop band of the transmission filter 240 and the pass band of the reception filter 220. Also, as the value of the common ground inductor 239 approaches 0.76 nH, the transmit zero moves down and further moves to the stop band of the receive filter 220 and the pass band of the transmit filter 240. For example, when the median value, i.e., the cross coupling capacitor 259 is approximately 0.26 pF and the common ground inductor 239 is approximately 0.38 nH, the frequency response of the transmit filter 240 at the center frequency of the receive filter 220 is Approximately -59.684 dB, and the frequency response of the receive filter 220 at the center frequency of the transmit filter 240 is approximately -54.576 dB.

In addition, there are fewer manufacturing parameters when manufacturing these receive and transmit filters 220 and 240 compared to conventional receive and transmit filters. Generating frequency shifting in some resonators requires separate control of the resonator regions of resonators 221-228 and resonators 241-248, and only two mass-loadings. Mass-loading is a material deposition layer on a particular resonator that is required to shift the corresponding resonant frequency of this resonator, depending on the design. For example, in the exemplary embodiment of the receive and transmit filters 220, 240 shown in FIG. 2, two intermediates of the transmit filter 240, in addition to the coarse mass-loading used for all shunt resonators, are shown. A series resonator (e.g., series resonators 242, 243) and first and final shunt resonators (e.g., shunt resonators 245, 248), and two intermediate series resonators (e.g., receive filter 220). For example, a second, smaller mass-loading for the series resonators 222, 223 and the final shunt resonator (e.g., the shunt resonator 228) provides a very rapid transition from the pass band to the stop band. Is enough. In addition, representative designs allow the use of minimum coupling coefficients in the required bandwidth, which makes the piezoelectric layer thinner and hence die size smaller. Furthermore, the same coupling coefficient can be used for all resonators 221-228, 241-248 in the receive and transmit filters 220, 240. Otherwise, if different effective coupling coefficients are required on different resonators, it will be difficult to control the relative resonator frequency since the thickness of the piezoelectric layer on the resonator must be changed to have different effective coupling constants.

4 and 5 are circuit diagrams illustrating a transmission filter 440 and a transmission filter 540 according to another exemplary embodiment, respectively. Like the transmission filter 240 described above, the transmission filters 440 and 540 are half-ladder filters with eight resonators and cross coupling capacitors, providing significant cancellation over the pass band to shift the transmission zero to a further stop band. do. The transmit filter 240, 440, 540 may also have a rapid roll-off on the high frequency side. The transmit filter 440, 540 may be included in the duplexer 200, for example, replacing the transmit filter 240. The transmit filter 440, 450 may also be used as a standalone band pass filter or included in a multiplexer or other device.

Referring to FIG. 4, the transmit filter 440 includes a series circuit including first to fourth transmit filter series resonators 441-444 connected in series between the antenna terminal 115 and the transmitter terminal 150. do. Transmit filter 440 also typically includes a shunt circuit, each of which includes first to fourth shunt resonators 445-448 and corresponding first to fourth inductors 455-458 connected between the series circuit and the ground voltage. It is provided. The series and shunt resonators 441-448 and inductors 455-458 may correspond substantially to and accordingly resonators 241-248 and inductors 255-258 as described above with reference to FIG. The description will not be repeated for the transmission filter 440.

In the exemplary embodiment shown, transmit filter 440 includes a connection of a different cross coupling capacitor than transmit filter 240. In particular, the fourth shunt resonator 448 has one end connected to the transmit terminal 150 and an opposite end connected to the first capacitance node 451, the opposite end being grounded through the fourth inductor 458. Is connected to. The first capacitance node is also connected to the second capacitance node 460 through the cross coupling capacitor 459. The second capacitance node 460 is located between the first and second series resonators 411 and 442. The first shunt resonator 445 has one end connected to the second capacitance node 460 and an opposite end connected to ground through the first inductor 455.

Referring to FIG. 5, the transmission filter 540 includes a series circuit including first to fourth transmission filter series resonators 541-544 connected in series between the antenna terminal 115 and the transmitter terminal 150. do. Transmit filter 540 also typically includes a shunt circuit, each of which includes first to fourth shunt resonators 545-548 and corresponding first to fourth inductors 555-558 connected between the series circuit and the ground voltage. It is provided. The transmit filter 540 further includes an additional inductor, i.e., the fifth inductor 560 described below. The series and shunt resonators 541-548 and inductors 555-558 may substantially correspond to the resonators 241-248 and inductors 255-258 described above with reference to FIG. It will not be repeated for the transmission filter 540.

In the exemplary embodiment shown, transmit filter 540 includes another connection of a cross coupling capacitor, unlike transmit filter 240. In particular, the third shunt resonator 547 has one end connected between the third and fourth series resonators 543 and 544 and an opposite end connected to the capacitance node 551 via the fourth inductor 557. do. Capacitance node 551 is connected to ground via a fifth inductor 560, and is connected to antenna terminal 115 via a cross coupling capacitor 559. In addition, the capacitance node 551 is also connected to the first and second shunt resonators 545, 546 through the first and second inductors 555, 556, respectively.

6A and 6B are circuit diagrams illustrating transmission filters 640a and 640b, respectively, in accordance with an exemplary embodiment. The transmission filters 640a and 640b are half-ladder filters similar to the transmission filter 240 described above with reference to FIG. 2 except that each includes an additional (ninth) resonator.

More specifically, referring to FIG. 6A, the transmission filter 640a includes an additional series resonator 649 connected in a series circuit between the fourth series resonator 644 and the transmitter terminal 150. Referring to FIG. 6B, the transmission filter 640b includes an additional shunt resonator 649 'in the additional shunt circuit. The additional shunt resonator 649 ′ has one end connected between the antenna terminal 115 and the first series resonator 642 and an opposite end connected to ground via an additional inductor 652. Other series and shunt resonators 641-648 and inductors 655-658 substantially correspond to the resonators 241-248 and inductors 255-258 described above with reference to FIG. It does not repeat for 640a or the transmission filter 640b.

In further exemplary embodiments, the transmission filters 440, 540 shown in FIGS. 4 and 5, respectively, may be in series or shunt in the same manner as shown in FIGS. 6A and 6B with reference to the transmission filter 240 of FIG. 2. It may be configured to include a ninth resonator as the resonator. In addition, the cross coupled capacitor 559 in the transmit filter 540 of FIG. 5 is alternatively inductor 555 separately grounded, and inductor 558 is inductor 556, 557 at an ungrounded node of inductor 560. Bonded to the node may be connected to a node between the resonator 541 and the resonator 542 and to a common ground inductor 560. It will also be appreciated that in various embodiments described herein, the antenna terminal 115 and the transmitter terminal 150 may have opposite positions with respect to the placement of the transmission filter without departing from the scope of the present invention. Those skilled in the art will also appreciate that in various embodiments, the size and / or values of resonators and cross-coupled capacitors may be modified to provide specific benefits for any particular situation or to meet specific design requirements for application to various implementations. I will understand.

7 and 8 are circuit diagrams illustrating receive filters 720, 820, respectively, according to a further exemplary embodiment. Like the receive filter 220 described above, the receive filters 720 and 820 are half-ladder filters with eight resonators and mutual inductance or common ground inductor, providing significant cancellation below the passband to further improve transmission zero. Shift to the stop band. Receive filters 240, 720, 820 may also have a rapid roll-off on the low frequency side. Receive filters 720 and 820 may be included in duplexer 200 in place of receive filter 220, for example. Receive filters 720 and 820 may also be used as standalone band pass filters or may be included in a multiplexer or other device.

Referring to FIG. 7, the receive filter 720 includes a series circuit including first to fourth receive filter series resonators 721-724 connected in series between the antenna terminal 115 and the receiver terminal 130. do. Although not shown in FIG. 7, it will be appreciated that a phase shifter or matching circuit may be included between node 733 and antenna terminal 115 depending on implementation and design requirements. Receive filter 720 also generally includes a first to fourth shunt resonator 725-728 and a corresponding first to fourth inductor 735-738, respectively, connected between the series circuit and the ground voltage. It is provided. The series and shunt resonators 721-728 and inductors 725-728 substantially correspond to the resonators 221-228 and inductors 235-238 described above in FIG. Do not repeat.

In the exemplary embodiment shown, receive filter 720 includes a connection of a common ground inductor 739 that is different from receive filter 240. In particular, the first shunt resonator 725 has one end connected to the node 733 and the opposite end connected to the mutual inductance node 732 via the first inductor 735. Similarly, the second shunt resonator 726 has one stage connected between the second and third series resonators 721 and 722 and the opposite stage connected to the mutual inductance node 732 via the second inductor 736. do. Mutual inductance node 732 is connected to ground through a mutual or common ground inductor 739.

In another embodiment of a receive filter (not shown), similar to the receive filters 220 and 720 of FIGS. 2 and 7, mutual inductance nodes (eg, node 732) are respectively the second and third inductors. (E.g., inductors 736 and 737) to the second and third shunt resonators (e.g., resonators 726 and 727). As in other embodiments, the mutual inductance node is connected to ground through a common ground inductor (eg, inductor 739).

Referring to FIG. 8, the receive filter 820 includes a series circuit including first to fourth receive filter series resonators 821-824 connected in series between the antenna terminal 115 and the receiver terminal 130. do. Although not shown in FIG. 8, it will be appreciated that depending on the implementation and design requirements, a phase shifter or matching circuit is included between the node 833 and the antenna terminal 115. Receive filter 820 also generally includes a shunt circuit, each of which includes first to fourth shunt resonators 825-828 and corresponding first to fourth inductors 835-838 connected between the series circuit and the ground voltage. It is provided. The series and shunt resonators 821-828 and inductors 835-838 substantially correspond to the resonators 221-228 and inductors 235-238 described above with reference to FIG. Will not be repeated.

In the exemplary embodiment shown, the receive filter 820 includes multiple cross couplings when compared to a single cross coupling of the receive filter 720 described above. In particular, receive filter 820 includes two mutual or common ground inductors 834, 839, each of which is a cross coupled inductor. Referring to FIG. 8, the first shunt resonator 825 has one end connected to the node 833, and an opposite end connected to the first mutual inductance node 832 through the first inductor 835, The second shunt resonator 826 has one stage connected between the first and second series resonators 821 and 822 and an opposite stage connected to the first mutual inductance node 832 via a second inductor 836. Equipped. Similarly, the third shunt resonator 827 has one stage connected between the second and third series resonators 822, 823, and the opposite side connected to the second mutual inductance node 831 via a third inductor 837. And a fourth shunt resonator 828 connected to the second mutual inductance node 831 through a fourth inductor 838 and one stage connected between the third and fourth series resonators 823 and 824. With opposite ends connected. The first mutual inductance node 832 is connected to ground through a common ground inductor 839, and the second mutual inductance node 831 is connected to ground through a second common ground inductor 834. This arrangement of multiple cross coupling circuits provides a filter having a substantially elliptical filter response.

9A and 9B are circuit diagrams illustrating receive filters 920a and 920b, respectively, in accordance with an exemplary embodiment. Receive filters 920a and 920b are half-ladder filters, like receive filter 220 described above with reference to FIG. 2 except that they each include an additional (ninth) resonator.

More specifically, referring to FIG. 9A, the receive filter 920a includes an additional series resonator 929 connected in a series circuit between the first series resonator 921 and the phase shifter 931, which phase shifter 931. ) Is connected in series with the antenna terminal 115. 9B, receive filter 920b includes an additional shunt resonator 929'in the additional shunt circuit. The additional shunt resonator 929 ′ has one stage connected between the receiver terminal 130 and the fourth series resonator 924 and an opposite stage connected to ground via an additional inductor 934. Other series and shunt resonators 921-928 and inductors 935-938 substantially correspond to the resonators 221-228 and inductors 235-238 described above with reference to FIG. 2. It will not repeat for 920a or receive filter 920b.

In a further exemplary embodiment, receive filters 720, 820 shown in FIGS. 7 and 8, respectively, refer to a ninth series in the same manner as shown in FIGS. 9A and 9B with reference to receive filter 240 of FIG. 2. Or shunt resonators. It will also be appreciated that with reference to the various embodiments described herein, the antenna terminal 115 and receiver terminal 130 may have opposite positions with respect to the placement of the receive filter without departing from the scope of the present invention. Also, in various embodiments, those skilled in the art will appreciate that the size and / or values of resonators and inductors may be varied to provide unique benefits for any particular situation or to meet specific design requirements for application to various implementations. I will understand.

10A and 10B are circuit diagrams illustrating a transmission resonator filter with multiple cross coupling capacitors in accordance with an exemplary embodiment. Similar to the transmission filter 240 described above, although each transmission filter 1040a, 1040b includes a plurality of cross-coupling capacitors 1059, 1060, the transmission filter 1040a, 1040b has a half- with eight resonators. Ladder filter. In general, in the illustrated embodiment, the first cross coupled capacitor circuit bypasses three consecutive series resonators, bypasses a shunt resonator connected to the third series resonator of the bypassed series resonator, while the second cross coupled capacitor circuit Bypasses two of the three consecutive series resonators and the same shunt resonator as above.

The transmit filters 1040a and 1040b may be included in the duplexer 200, for example, replacing the transmit filter 240. The transmit filter 1040a, 1040b may also be used as a standalone band pass filter or included in a multiplexer or other device. Moreover, the configuration of the transmission filters 1040a and 1040b need not be used to filter the uplink signal but may be used to filter the downlink signal or in any situation that requires an upshift of the signal transmission zero. have.

Referring to FIG. 10A, the transmission filter 1040a includes first to fourth filter series resonators (s) connected in series between an antenna terminal 115 (or another output node) and a transmitter terminal 150 (or another input node). 1041-1044). The transmit filter 1040a also generally includes a first to fourth shunt resonator 1045-1048 and a corresponding first to fourth inductor 1055-1058, respectively, connected between the series circuit and the ground voltage. It is provided.

More specifically, in the exemplary embodiment shown, the first shunt resonator 1045 includes one stage (eg, top electrode) connected between the first and second series resonators 1041, 1042, and the inductor 1055. And an opposite end (e.g., lower electrode) connected to ground via < RTI ID = 0.0 > The second shunt resonator 1046 has one end connected between the second and third series resonators 1042 and 1043 and an opposite end connected to ground through an inductor 1056. The third shunt resonator 1047 has one stage connected between the third and fourth series resonators 1043 and 1044 and an opposite stage connected to the first capacitance node 1051 connected to ground through the inductor 1057. It is provided. The fourth shunt resonator 1048 most closely connected to the transmitter terminal 150 has one stage connected between the fourth series resonator 1044 and the transmitter terminal 150 and is connected to ground through an inductor 1058. With the opposite end.

In addition, the first capacitance node 1051 is connected to two cross coupling circuits, each of which includes a first cross coupling capacitor 1059 and a second cross coupling capacitor 1060. In the illustrated embodiment, the first capacitance node 1051 is connected to the antenna terminal 115 through a first cross coupling capacitor 1059 and to the second capacitance node 1061 through a second cross coupling capacitor 1060. Connected. Second capacitance node 1061 is positioned between first and second series resonators 1041 and 1042.

In comparison, the cross coupling circuit of FIG. 10B is shifted against the series resonator. Referring to FIG. 10B, the transmission filter 1040b includes a series circuit including first to fourth filter series resonators 1041-1044 connected in series between the antenna terminal 115 and the transmitter terminal 150. . The transmission filter 1040b also generally includes a first to fourth shunt resonator 1045-1048 and a corresponding first to fourth inductor 1055-1058, respectively, connected between the series circuit and the ground voltage. It is provided.

More specifically, in the exemplary embodiment shown, the first shunt resonator 1045 includes one stage (eg, top electrode) connected between the first and second series resonators 1041, 1042, and an inductor ( An opposite end (eg, bottom electrode) connected to ground via 1055. The second shunt resonator 1046 has one end connected between the second and third series resonators 1042 and 1043 and an opposite end connected to ground through an inductor 1056. The third shunt resonator 1047 has one end connected between the third and fourth series resonators 1043 and 1044 and an opposite end connected to ground through the inductor 1057. The fourth shunt resonator 1048 most closely connected to the transmitter terminal 150 has one stage connected between the fourth series resonator 1044 and the transmitter terminal 150 and is connected to ground through an inductor 1058. An opposite end connected to the first capacitance node 1052.

In addition, the first capacitance node 1052 is connected to two cross coupling circuits each including a first cross coupling capacitor 1059 and a second cross coupling capacitor 1060. In the illustrated embodiment, the first capacitance node 1052 is connected to the second capacitance node 1061 through the first cross coupling capacitor 1059 and the third capacitance node (1060) through the second cross coupling capacitor 1060. 1062). The second capacitance node 1061 is located between the first and second series resonators 1041 and 1042, and the third capacitance node 1062 is located between the second and third series resonators 1042 and 1043.

More generally speaking, in some embodiments the first cross coupled capacitor 1059 is a first node (e.g., connected to at least one series resonator 1041-1044 (e.g., series resonator 1041 or 1042). For example, a connection between an antenna terminal 115 or a capacitance node 1061 and a second node connected to one of the shunt resonators (for example, the shunt resonator 1047 or 1048) of the shunt resonator 1045-1048. do. Three series resonators (e.g., series resonators 1041-1043 or series resonators 1042-1044) and one shunt resonator (e.g., shunt resonators 1047 or 1048) between the first and second nodes. ) Exists. The second cross coupled capacitor 1060 is a third node (eg, capacitance node 1061 or 1062) connected to at least one series resonator 1041-1044 (eg, series resonator 1042 or 1043). ) And a second node connected to one of the shunt resonators (for example, the shunt resonators 1047 or 1048) of the shunt resonators 1045-1048. There are two series resonators (e.g., series resonators 1042-1043 or 1043-1044) and one shunt resonator (e.g., shunt resonators 1047 or 1048) between the third and second nodes. . The second node (eg, capacitance node 1051) is isolated from ground voltage by an inductor (eg, inductor 1057). In other words, the first cross coupling circuit is configured to bypass n series resonators (where n is an integer) and one shunt resonator, while the second cross coupling circuit comprises n-1 series resonators (of n series resonators) and And bypass the same shunt resonator. This arrangement of multiple cross coupling circuits provides a filter having a substantially elliptical filter response.

In various embodiments, the transmit filter 1040a or 1040b may also use a receive filter, such as the receive filter 220, 720, 820, 920a or 920b shown in FIGS. 2, 7, 8, 9a and 9b, respectively. It may be included in an included duplexer (eg, duplexer 100). Also, in various embodiments, both the transmit and receive filters of the duplexer may include multiple cross coupled circuits. For example, a representative duplexer may include a transmission filter 1040a or 1040b having a plurality of cross coupling capacitors (eg, first and second cross coupling capacitors 1059 and 1060), and a plurality of cross couplings in FIG. 8. And receive filter 820 with an inductor (mutual or common ground inductors 834, 839).

10A and 10B, each series and shunt resonator 1041-1048 may be, for example, an FBAR including a thin film piezoelectric layer formed in a stacked structure between upper and lower electrodes. The thin film piezoelectric layer may be formed of aluminum nitride, PZT or other film suitable for semiconductor processing. In one embodiment, series and shunt resonators 1041-1048 are fabricated using a common layer of piezoelectric material. Also in one embodiment, the series and shunt resonators 1041-1048 can be fabricated using a common layer of piezoelectric material. In addition, only two mass-loadings are required to produce a frequency shift within the resonators of some of the resonators 1041-1048, as described below. The upper and lower electrodes can be formed of any conductive metal suitable for semiconductor processes, such as molybdenum, tungsten, aluminum, and the like.

In various embodiments, the series and shunt resonators 1041-1048 of the transmission filters 1040a and 1040b have the same coupling coefficients, and all series and shunt resonators 1041-1048 include piezoelectric layers having the same thickness. When the transmit filter 1040a or 1040b is included in the duplexer, the coupling coefficients and / or piezoelectric layer thicknesses of the series and shunt resonators 1041-1048 may or may not be the same as the values of the series and shunt resonators of the receive filter. As also described above, it is possible to use the minimum coupling coefficient for the required bandwidth, which makes the piezo layer thinner and therefore the die size smaller.

Also as described above, four different frequencies are required by only two mass-loadings to generate frequency shifts in some of the series and shunt resonators of the transmit and receive filters with multiple cross couplings. Can be generated. For example, in the exemplary embodiment of the transmission filter 1040a shown in FIG. 10A, only the first (assembled) mass-loading is applied to the second and third shunt resonators 1046, 1047, and the second (particulate) ) Only mass-loading is applied to the first, second and third series resonators 1041, 1042, 1043, and the first and second mass-loading are applied to the first and fourth shunt resonators 1045, 1048. And mass-loading is not applied to the fourth series resonator 1044. Likewise, in the exemplary embodiment of the receive filter 820 shown in FIG. 8, the first and second mass-loadings are applied to the first and fourth shunt resonators 825, 828 and only the second mass-loadings. The second and third series resonators 822 and 823 and the second and third shunt resonators 826 and 827 are applied, and mass-loading is not applied to the first and fourth series resonators 821 and 824.

 The first and second cross coupled capacitors 1059, 1060 of the transmission filters 1040a, 1040b are transmitted together with an inductor (eg, third or fourth inductor 1057 or 1058) connecting to ground ( Shifts the transmission zero of the uplink) signal high above the pass band of the transmission filter 1040a or 1040b to reach the middle of its stop band. The values of the first and second cross coupled capacitors 1059 and 1060 and the values of the inductor 1057 or 1058 determine the extent to which the transmission zero shifts up in frequency from the upper edge of the pass band. For example, in one embodiment where the transmit filter 1040a or 1040b is included in the duplexer, the values of the first and second cross coupled capacitors 1059 and 1060 and / or the values of the inductor 1057 or 1058 are transmitted. The zero point is selected to shift to or near the center frequency of the receive filter pass band. The frequency placement of this transmission zero (and pole) allows for nearly ideal elliptical filter performance.

Thus, in various embodiments, those skilled in the art will appreciate that the size and / or value of the resonator, inductor and cross-coupled capacitors may be modified to provide specific benefits for any particular situation or to meet specific design requirements for application to various implementations. I understand that it is changeable. For example, assuming that the center frequency of the pass band 1040a or 1040b passband is approximately 887.2 MHz and the center frequency of the corresponding receive filter (within the duplexer configuration) pass band is approximately 943.3 MHz, the first cross coupling Capacitor 1059 may have a value of approximately 0.1 pF, and second cross-coupled capacitor 1060 may have a value of approximately 0.8 pF. The value of inductor 1055-1058 may be a value between approximately 0.3 nH and 0.7 nH (typical wirebond value). Each series and shunt resonator 1041-1048 may be an FBAR having an area in the range of approximately 1000-100,000 μm ² , depending on the frequency and bandwidth conditions of the filter / duplexer and the optimum impedance for each particular resonator.

FIG. 11 is a circuit diagram illustrating a transmission resonator filter having a plurality of cross coupled capacitors according to an exemplary embodiment. FIG. 11 shows a transmission filter 1140, which is a half-ladder filter with first and second cross coupling capacitors 1159, 1160. In general, the configuration of the transmission filter 1140 is such that the first cross coupled capacitor circuit bypasses three consecutive series resonators and shunt resonators, and the second cross coupled capacitor circuit bypasses two consecutive series resonators and shunt resonators. It is similar to the configuration of the transmission filters 1040a and 1040b shown in Figs. 10A and 10B in that, but in the embodiment shown in Fig. 11, the first and second cross coupling circuits bypass different shunt resonators. The second cross coupling circuit bypasses at least one series resonator that is not bypassed by the first cross coupling circuit.

The transmit filter 1140 may be included in the duplexer 200, for example, replacing the transmit filter 240. The transmit filter 1140 may be used as a standalone band pass filter or may be included in a multiplexer or other device. Moreover, the configuration of the transmit filter 1140 need not be used to filter the uplink signal but can be used to filter the downlink signal or in any situation that requires an upshift of the signal transmission zero.

Referring to FIG. 11, the transmission filter 1140 includes a series circuit including first to fourth series resonators 1141-1144 connected in series between the antenna terminal 115 and the transmitter terminal 150. The transmit filter 1140 also typically includes a shunt circuit, each of which includes a first to fourth shunt resonator 1145-1148 and a corresponding first to fourth inductor 1155-1158 connected between the series circuit and the ground voltage. It is provided.

More specifically, in the exemplary embodiment shown, the first shunt resonator 1145 includes one stage (eg, top electrode) connected between the first and second series resonators 1141, 1142, and an inductor ( An opposite end (eg, bottom electrode) connected to ground via 1155. The second shunt resonator 1146 has one end connected between the second and third series resonators 1142 and 1143 and an opposite end connected to ground through an inductor 1156. The third shunt resonator 1147 has one stage connected between the third and fourth series resonators 1143 and 1144 and an opposite stage connected to the first capacitance node 1151 connected to ground through the inductor 1157. It is provided. The fourth shunt resonator 1148 connected closest to the transmitter terminal 150 is connected to the second capacitance node 1152 and one stage connected between the fourth series resonator 1144 and the transmitter terminal 150. With the opposite end, the second capacitance node 1152 is connected to ground through an inductor 1158.

In addition, the first capacitance node 1151 is connected to a first cross coupling circuit including a first cross coupling capacitor 1159 connected between the first capacitance node 1151 and the antenna terminal 115. Thus, the first cross coupling circuit bypasses three series resonators (first, second and third series resonators 1141, 1142, 1143) and one shunt resonator (third shunt resonator 1147). The second capacitance node 1152 is the second cross coupled capacitor 1160 connected between the second capacitance node 1152 and the third capacitance node 1162 (located between the second series resonators 1142 and 1143). Is connected to a second cross-coupling circuit comprising a. The second cross coupling circuit thus bypasses two series resonators (third and fourth series resonators 1143 and 1144) and one shunt resonator (fourth shunt resonator 1148). In other words, the first cross coupling circuit is configured to bypass n series resonators (where n is an integer) and one shunt resonator, while the second cross coupling circuit comprises n-1 series resonators (at least one of which is the first). Different from a series resonator bypassed by a cross coupling circuit) and a shunt resonator other than the above.

Various other embodiments may include a transmission filter with additional cross coupling capacitors and / or additional (or fewer) series and / or shunt resonators without departing from the scope of the present invention. For example, the configuration of the first and second cross coupled capacitor circuits shown in FIGS. 10A, 10B, and 11 may include five series resonators and four shunt resonators, as shown in FIG. 6A, or as shown in FIG. 6B. Likewise, it can be implemented in a transmission filter having nine (or more) resonators, such as four series resonators and five shunt resonators. Likewise, various other embodiments may include receive filters with additional cross coupled inductors and / or additional (or fewer) series and / or shunt resonators without departing from the scope of the present invention. For example, the configuration of the first and second cross coupled inductor circuits shown in FIG. 8 may include five series resonators and four shunt resonators as shown in FIG. 9A or four series resonators as shown in FIG. It can be implemented in a receive filter with nine (or more) resonators, such as five shunt resonators.

According to various embodiments, all eight poles of a plurality of crosslinked filters may be located in nearly ideal positions, and all eight zeroes may be located in an improved position over conventional filters, thus providing roughly over the entire passband. Nearly perfect roll-off with a return loss of -17 dB can be achieved. This means low insertion loss and low reflected power. With the high quality factors of current FBARs (eg having thousands of quality factors), the peak current savings for the end user compared to conventional filters can result in insertion loss. This can correspond to an improvement of approximately ~ 1dB (e.g., approximately 66mA).

For example, when used as a standalone filter or contained within a duplexer, multiplexer, or the like, the improved performance of all of the above-described embodiments over conventional transmit and receive filters is, for example, UMTS band 2 (PCS band). Passband due to very narrow guard bands, such as in UMTS band 3 (GCS), UMTS band 7 (IMT-E), UMTS band 8 (GSM-900), and 3GPP bands 13 and 14. This is particularly advantageous where very rapid roll-off from to the stop band is required. Of course, it will be appreciated that various embodiments may be adjusted to cover all UMTS bands, even if a sudden roll-off is not required. For example, even when abrupt roll-off is not required, several embodiments allow the use of a minimum effective coupling coefficient and piezoelectric layer (eg, AlN) thickness to obtain a given bandwidth, at a given impedance. It has a minimum resonator area, which results in a smaller dice size and a lower cost.

Numerous components, materials, structures, and variables are included in the manner of description and are for illustrative purposes only and not for the purpose of any limitations. Given this specification, one of ordinary skill in the art would be able to practice the disclosure of the present invention to determine its own field of application and the necessary parts, materials, structures and devices for carrying out its application without departing from the scope of the appended claims. will be.

Claims (20)

A filter device for filtering a signal,
A plurality of series resonators connected in series between one of the transmitters or receivers and the antenna,
A plurality of shunt resonators connected between at least one of the series resonators and a ground voltage, respectively;
A plurality of cross coupled circuits configured to bypass at least two series resonators of the plurality of series resonators and at least one shunt resonator of the plurality of shunt resonators
Filter device comprising a.
The method of claim 1,
Each of the plurality of cross coupling circuits comprises a capacitor connected between a corresponding first node connected to at least one of the bypassed series resonators and a second node connected to the bypassed shunt resonator,
The second node is connected to ground via an inductor
Filter device.

The method of claim 2,
And the plurality of cross coupling circuits are connected to the same second node.
The method of claim 1,
The plurality of cross coupled circuits
A first cross coupling circuit configured to bypass n series resonators of the plurality of series resonators (n is an integer) and one of the plurality of shunt resonators;
A second cross coupling circuit configured to bypass n-1 series resonators of the plurality of series resonators and one shunt resonator of the plurality of shunt resonators
Filter device comprising a.
The method of claim 4, wherein
Wherein the first cross coupling circuit comprises a first capacitor and the second cross coupling circuit comprises a second capacitor.

The method of claim 5, wherein
And the n-1 series resonators bypassed by the second cross coupling circuit are included between the n series resonators bypassed by the first cross coupling circuit.
The method of claim 5, wherein
The one shunt resonator bypassed by the second cross coupled circuit is the same filter device as the one shunt resonator bypassed by the first cross coupled circuit.
The method of claim 5, wherein
The one shunt resonator bypassed by the second cross coupling circuit is different from the one shunt resonator bypassed by the first cross coupling circuit.
The method of claim 1,
The first shunt resonator is connected to one end between the first series resonator and the second series resonator, the second shunt resonator is connected to one end between the second series resonator and the third series resonator, and the third shunt A resonator is connected to one end between the third and fourth series resonators, and a fourth shunt resonator is connected to one end between the fourth series resonator and one of the receiver or the transmitter.
The method of claim 9,
A first cross coupling circuit comprises a first capacitor having one end connected between the antenna and the first series resonator and the other end connected to the third shunt resonator,
The second cross coupling circuit includes a second capacitor having one end connected between the first series resonator and the second series resonator and another end connected to the third shunt resonator.
Filter device.
The method of claim 9,
The first cross coupling circuit includes a first capacitor having one end connected between the first series resonator and the second series resonator and the other end connected to the fourth shunt resonator,
The second cross coupling circuit includes a second capacitor having one end connected between the second series resonator and the third series resonator and the other end connected to the fourth shunt resonator.
Filter device.
The method of claim 9,
A first cross coupling circuit includes a first capacitor having one end connected between the antenna and the first series resonator and the other end connected to the third shunt resonator,
The second cross coupling circuit includes a second capacitor having one end connected between the second series resonator and the third series resonator and the other end connected to the fourth shunt resonator.
Filter device.
A duplexer that interfaces a receiver and a transmitter with a common antenna,
A plurality of first series resonators connected in series between the antenna and one of the receiver or the transmitter, a plurality of first shunt resonators respectively connected between at least one of the first series resonators and a ground voltage, and a plurality of A first filter comprising a first cross coupled circuit,
A plurality of second series resonators connected in series between the antenna and one of the transmitter or the receiver, a plurality of second shunt resonators respectively connected between at least one of the second series resonators and the ground voltage, A second filter comprising a second cross coupled circuit of
Duplexer comprising a.
The method of claim 13,
The plurality of first cross coupled circuits includes a corresponding plurality of inductors,
Each inductor is connected between at least two of the first shunt resonators and the ground voltage
Duplexer.
The method of claim 14,
The first filter has a first passband,
The plurality of first cross coupled circuits allows a first transmission zero to shift at a lower frequency from the lower edge of the first pass band.
Duplexer.
The method of claim 13,
The plurality of second cross coupling circuits includes a corresponding plurality of capacitors,
Each second cross coupling circuit bypasses at least two second series resonators of the plurality of second series resonators and a second shunt resonator of one of the plurality of second shunt resonators.
Duplexer.
17. The method of claim 16,
The second filter has a second pass band,
The plurality of second cross coupling circuits allow a second transmission zero to be shifted to a higher frequency from the upper edge of the second pass band.
Duplexer.
The method of claim 13,
Each of the first series resonator and the second series resonator and each of the first shunt resonator and the second shunt resonator use film bulk acoustic resonators (FBARs) formed using two or less mass-loadings. Containing
Duplexer.
The method of claim 13,
And the first series resonator and the second series resonator, the first shunt resonator and the second shunt resonator have the same coupling coefficient.
Half-ladder filter having a pass band,
A plurality of series resonators connected in series between an input node and an output node,
A plurality of shunt resonators connected between at least one of the series resonators and a ground voltage, respectively;
A plurality of cross coupled circuits comprising a corresponding plurality of capacitors,
Each cross coupling circuit bypasses at least two series resonators of the plurality of series resonators and at least one shunt resonator of the plurality of shunt resonators,
The plurality of cross coupling circuits allow transmission zeros to shift to higher frequencies from the upper edge of the pass band of the filter.
Half-ladder filter.

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