WO2021143520A1 - 一种滤波器、双工器、高频前端电路及通信装置 - Google Patents

一种滤波器、双工器、高频前端电路及通信装置 Download PDF

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Publication number
WO2021143520A1
WO2021143520A1 PCT/CN2020/140941 CN2020140941W WO2021143520A1 WO 2021143520 A1 WO2021143520 A1 WO 2021143520A1 CN 2020140941 W CN2020140941 W CN 2020140941W WO 2021143520 A1 WO2021143520 A1 WO 2021143520A1
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series
parallel
inductors
branch
inductor
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PCT/CN2020/140941
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English (en)
French (fr)
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庞慰
边子鹏
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诺思(天津)微系统有限责任公司
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • H03H9/703—Networks using bulk acoustic wave devices
    • H03H9/706—Duplexers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material

Definitions

  • the present invention relates to the technical field of filters, in particular to a filter, a duplexer, a high-frequency front-end circuit and a communication device.
  • the radio frequency filter plays a vital role. It can filter out-of-band interference and noise to meet the requirements of the radio frequency system and The requirements of the communication protocol for signal-to-noise ratio.
  • Radio frequency filters are mainly used in wireless communication systems, such as radio frequency front-ends of base stations, mobile phones, computers, satellite communications, radars, electronic countermeasures systems, and so on.
  • the main performance indicators of radio frequency filters are insertion loss, out-of-band suppression, power capacity, linearity, device size and cost.
  • Good filter performance can improve the data transmission rate, life and reliability of the communication system to a certain extent. Therefore, the design of high-performance and simplified filters for wireless communication systems is very important.
  • the small-size filter devices that can meet the needs of communication terminals are mainly piezoelectric acoustic wave filters.
  • the resonators that constitute this type of acoustic wave filter mainly include: FBAR (Film Bulk Acoustic Resonator), SMR (Solidly Mounted Resonator, solid-state assembly resonator) and SAW (Surface Acoustic Wave, surface acoustic wave resonator).
  • FBAR Flexible Bulk Acoustic Resonator
  • SMR Solidly Mounted Resonator, solid-state assembly resonator
  • SAW Surface Acoustic Wave, surface acoustic wave resonator
  • the filters manufactured based on the principle of bulk acoustic wave FBAR and SMR collectively referred to as BAW, bulk acoustic wave resonator
  • BAW bulk acoustic wave resonator
  • LTCC Low-temperature co-fired ceramic
  • the main purpose of the present invention is to provide a filter, a duplexer, a high-frequency front-end circuit and a communication device, which help to improve the roll-off characteristics of the filter and reduce the insertion loss near the series resonance frequency of the resonator. Characteristics, and improve the filter's far-band suppression characteristics.
  • a filter which includes a first series branch and a plurality of parallel branches located between the input end and the output end of the filter; the parallel branch One end is located on the first series branch, and the other end is grounded.
  • the filter further includes at least one second series branch between the input end and the output end of the filter, and the second series branch includes an inductor. ; And for the whole constituted by the first series branch and the second series branch, there is at least one acoustic resonator in the whole, and the acoustic resonator is connected in series with the inductance in the series branch where it is located.
  • the first series branch includes two series-connected inductors, and a capacitor is connected in series between the two inductors;
  • the second series branch includes two series-connected inductors, and an acoustic resonator is connected in series between the two inductors;
  • the parallel branch includes Two parallel resonant units.
  • Each parallel resonant unit includes a capacitor and an inductor in parallel. The two parallel resonant units are respectively connected to the input end series branch node and the output end series branch node, and the other end is connected to the inductor respectively. One end is connected to the ground inductance in common.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series;
  • the second series branch includes two inductors connected in series, and the series acoustic resonance between the two inductors
  • Parallel branch includes three parallel resonant units, each parallel resonant unit includes parallel capacitance and inductance, the three parallel resonant units are connected to the input end series branch node, the series resonant unit connection node, and the output end series branch node Connect, the other end is grounded.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series;
  • the second series branch includes two inductors connected in series, and the series acoustic resonance between the two inductors
  • Parallel branch includes three parallel resonant units, each parallel resonant unit includes parallel capacitance and inductance, two parallel resonant units are respectively connected to the input end series branch node and the output end series branch node, and the other ends are respectively connected Inductance, one end of the two inductances is commonly connected to the grounding inductance; one end of the other parallel resonant unit is connected to the connection node of the series resonant unit, and the other end is connected to the inductor, and the inductance is grounded.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series;
  • the second series branch includes two inductors connected in series, and the series acoustic resonance between the two inductors
  • Parallel branch includes three parallel resonant units, each parallel resonant unit includes parallel capacitance and inductance, the three parallel resonant units are connected to the input end series branch node, the series resonant unit connection node, and the output end series branch node Connect the inductors at the other end, and the three inductors are grounded.
  • the first series branch includes two series resonant units connected in series, each series resonant unit includes a capacitor and an inductor connected in series;
  • the second series branch includes two series inductors, and two inductors are connected in series.
  • Acoustic wave resonators of different frequencies the two acoustic wave resonators are connected in parallel;
  • the parallel branch includes three parallel resonant units, each parallel resonant unit includes a parallel capacitor and an inductance, and the two parallel resonant units are connected in series with the input end of the branch node respectively It is connected to the output terminal series branch node, and the other end is respectively connected to an inductor, one end of the two inductors is commonly connected to a grounding inductor; one end of the other parallel resonant unit is connected to the series resonant unit connection node, and the other end is connected to an inductor, and the inductor is grounded.
  • the first series branch includes two inductances connected in series, and two acoustic resonators of different frequencies are connected in series between the two inductances, and the two acoustic resonators are connected in series;
  • the second series branch includes two inductances connected in series.
  • Inductance a series capacitor between two inductors;
  • the parallel branch includes three parallel resonant units, each parallel resonant unit includes a parallel capacitor and an inductance, two parallel resonant units are connected to the input end series branch node and the output end series branch respectively
  • One end of the two inductors is connected to the grounding inductor together;
  • one end of the other parallel resonant unit is connected to the connection node between the acoustic wave resonator, and the other end is connected to the inductor, and the inductor is grounded.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series;
  • the second series branch includes two inductors connected in series, and the series acoustic resonance between the two inductors
  • the parallel branch includes three parallel resonant units, each parallel resonant unit includes parallel acoustic resonators and inductors, two parallel resonant units are respectively connected to the input end series branch node and the output end series branch node, the other end
  • the inductors are respectively connected, and one end of the two inductors is commonly connected to the grounding inductor; one end of the other parallel resonant unit is connected to the connection node of the series resonant unit, and the other end is connected to the inductor, and the inductor is grounded.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series;
  • the second series branch includes two series-connected inductors, and an acoustic wave resonator is connected in series between the two inductors;
  • the parallel branch includes three parallel resonant units, and each parallel resonant unit includes parallel capacitors and inductances.
  • One end of the three parallel resonant units is respectively connected to the input end series branch node, the series resonant unit connection node and the output end series branch.
  • the other end is connected to the inductance; among them, the inductance connected to the parallel resonant unit connected to the connection node of the series resonant unit is grounded, and the inductances connected to the other two parallel resonant units are respectively connected to the ground
  • the nodes between the inductors are connected through the first inductor.
  • the two inductors connected to the two parallel resonant units connected to the input end series branch node and the output end series branch node form a coupling structure with mutual inductance.
  • a duplexer including the above-mentioned filter.
  • a high-frequency front-end circuit including the above-mentioned filter.
  • a communication device including the above-mentioned filter.
  • An acoustic wave resonator is installed on the first series branch or the second series branch between the input end series branch node and the output end series branch node, and the high-Q characteristics of the acoustic wave resonator are used to ensure the difference between Fs and Fp
  • the area between is used to form the fast roll-off edge of the filter, which effectively improves the roll-off characteristics of the filter;
  • Figure 1a is the electrical symbol of the piezoelectric acoustic wave resonator
  • Figure 1b is an equivalent electrical model diagram of a piezoelectric acoustic resonator
  • Figure 2 is the relationship between the resonator impedance and fs and fp;
  • Fig. 3 is a schematic cross-sectional view of the structure of a bulk acoustic wave resonator
  • Figure 4 is a circuit diagram of the comparative example
  • FIG. 5 is a schematic diagram of the topology structure of the filter provided in this embodiment.
  • FIG. 6 is a schematic diagram of the topology structure of the first embodiment provided by this embodiment.
  • FIG. 7 is a schematic diagram of the topology structure of the second embodiment provided by this embodiment.
  • Fig. 8 is an equivalent circuit diagram of the series branch circuit under the condition of the circuit structure of the comparative example without considering the parallel branch circuit;
  • Fig. 9 is an equivalent circuit diagram of the circuit structure of the first embodiment without considering parallel branches;
  • 10 is the impedance frequency characteristic of the acoustic wave resonator and the comparison diagram of the impedance frequency characteristic of the series branch 400 of the comparative example and the series branch 401 of the first embodiment;
  • Fig. 11 is a comparison of roll-off characteristics between the first embodiment and the second embodiment
  • Figure 12 is a structural diagram of a parallel branch circuit of a comparative example
  • FIG. 13 is a structural diagram of a parallel branch circuit of the second embodiment
  • FIG. 16 is a schematic diagram of the topology structure of the filter provided by the third embodiment.
  • FIG. 17 is a schematic diagram of the topology structure of the filter provided in the fourth embodiment.
  • FIG. 19 is a schematic diagram of the topology structure of the filter provided in the sixth embodiment.
  • FIG. 20 is a schematic diagram of the topology structure of the filter provided in the seventh embodiment.
  • Figure 21 shows the out-of-band suppression characteristics of different inductance coupling M when the series inductance of the parallel branch is equal to 0.15nH;
  • Fig. 22 is a three-dimensional circuit model of the second embodiment.
  • Figure 1a is the electrical symbol of the piezoelectric acoustic wave resonator
  • Figure 1b is its equivalent electrical model diagram.
  • the electrical model is simplified to a resonant circuit composed of Lm, Cm, and C0.
  • the resonant circuit has two resonant frequencies: one is the fs when the impedance of the resonant circuit reaches a minimum value, and fs is defined as the series resonant frequency of the resonator; the other is when the impedance of the resonant circuit When fp reaches the maximum value, fp is defined as the parallel resonance frequency of the resonator. in,
  • Kt 2 eff (hereinafter abbreviated as Kt 2 ) of the resonator
  • Figure 2 is the relationship between the resonator impedance and fs and fp.
  • the impedance amplitude of the resonator at fs is defined as Rs, which is the minimum value in the impedance curve of the resonator;
  • the impedance amplitude of the resonator at fp is defined as Rp, which is the value in the impedance curve of the resonator maximum.
  • Rs and Rp are important parameters describing resonance loss characteristics. When Rs is smaller and Rp is larger, the loss of the resonator is smaller, the Q value is higher, and the insertion loss characteristics of the filter are also better at this time.
  • FIG. 3 is a schematic cross-sectional view of the structure of the thin film bulk acoustic wave resonator, 61 is the semiconductor substrate material, 65 is the air cavity obtained by etching, the bottom electrode 63 of the thin film bulk acoustic resonator is deposited on the semiconductor substrate 61, 62 It is a piezoelectric film material, and 64 is a top electrode.
  • the area selected by the dashed line is the overlapping area of 65 air cavity, 64 top electrode, 63 bottom electrode and 62 piezoelectric layer is the effective resonance area.
  • the material of the top electrode and the bottom electrode can be made of gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), titanium tungsten (TiW), aluminum (Al) ), titanium (Ti) and other similar metals;
  • the material of the piezoelectric layer can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz) , Potassium niobate (KNbO3) or lithium tantalate (LiTaO3), etc.
  • the thickness of the piezoelectric film is generally less than 10 microns.
  • the aluminum nitride film is in a polycrystalline form or a single crystal form, and the growth method is thin film sputtering or metal organic chemical vapor deposition (MOCVD).
  • FIG. 4 is a circuit structure diagram of the existing LC filter 100 (comparative example).
  • two series capacitors are provided between the input terminal series branch node P1 and the output terminal series branch node P2. They are respectively C1 and C2, the input terminal series branch node P1 and the input terminal T1 are provided with an inductor L1, the output terminal series branch node P2 and the output terminal T2 are provided with an inductor L2, the input terminal series branch node P1
  • the line between the capacitors C1 and C2 and the output terminal series branch node P2 are respectively connected to the parallel branch.
  • the parallel branch includes the parallel capacitor C3 and the inductor L3 as shown in the figure, the parallel capacitor C4 and the inductor L4, and the parallel The capacitor C5 and the inductance L5, the other end of the three parallel branches is grounded.
  • the existing LC filter has poor insertion loss, out-of-band suppression, and roll-off performance due to the limitation of the Q value of the LTCC.
  • the LTCC has poor far-band suppression characteristics due to the presence of the lead-inductor.
  • this embodiment proposes a new filter, which adds a series branch on the basis of the existing filter, and installs an acoustic wave filter on any series branch to form a combined type. filter.
  • FIG. 5 is a schematic diagram of the topology structure of the filter provided by this embodiment.
  • the first series branch includes two series inductors L0, and a series capacitor C1 is connected between the two inductors L0;
  • the second series branch includes Two serial inductors L0, and a series acoustic resonator RES1 between the two inductors L0;
  • the parallel branch includes two parallel resonant units, each parallel resonant unit includes parallel capacitors and inductors, in the figure C2, C3, L3, L4, the two parallel resonant units are respectively connected to the input series branch node P1 and the output series branch node P2, and the other ends are connected to inductors L5 and L6 respectively.
  • FIG. 6 is a schematic diagram of the topology of the filter of another structure provided in this embodiment; in the figure, the first A series branch includes two series series resonant units, each series resonant unit includes a series capacitor and an inductance, C2, C3 and L0 connected to it in the figure; the second series branch includes two series inductance L0, The acoustic resonator RES1 is connected in series between the two inductors L0; the parallel branch includes three parallel resonant units, and each parallel resonant unit includes parallel capacitors and inductors, as shown in the figure C4 and L3, C5 and L4, C6 and L5 in parallel ; The three parallel resonant units are respectively connected to the input end series branch node P1, the series resonant unit connection no
  • the first series branch includes two series resonant units, each series resonant unit includes a series capacitor and an inductance, respectively, two L0, C2 and C3;
  • the second series branch includes two The series inductance L0, the acoustic resonator RES1 is connected in series between the two inductances;
  • the parallel branch includes three parallel resonant units, and each parallel resonant unit includes parallel capacitors and inductors, respectively C4 and L3, C5 and L4 in parallel,
  • C6 and L5 the two parallel resonant units are respectively connected to the input series branch node P1 and the output series branch node P2, and the other ends are respectively connected to inductors L6 and L8, and one end of the two inductors is commonly connected to the grounding inductor LM;
  • One end of the other parallel resonant unit is connected to the connection node of the series resonant unit, and the other end is connected to an inductor L7, which is grounded.
  • FIG. 8 shows the equivalent circuit diagram 400 of the series branch under the condition of the comparative circuit structure 100 without considering the parallel branch, where the inductor LE is the equivalent inductance of the series branch, and the capacitor CE is the equivalent capacitance of the series branch.
  • FIG. 9 shows the equivalent circuit diagram 401 of the circuit structure 300 of the first embodiment without considering parallel branches, in which the inductor LE is the equivalent inductance of the series branch, the capacitor CE is the equivalent capacitance of the series branch, and 2L0 represents the series inductance of the input and output terminals.
  • the solid line is the impedance frequency characteristic curve of the resonator RES in Fig. 9, and the dotted line DOT is the impedance frequency characteristic curve of the equivalent circuit shown in Fig. 9.
  • the series connection of the resonator after the resonator RES is connected in series with the equivalent inductance The resonator frequency Fs moves to the low frequency end. Because the series equivalent inductance is relatively small, the series resonance frequency Fs of the 401 equivalent circuit is almost unchanged. After the resonator RES is connected in parallel with the equivalent capacitor, the parallel resonator frequency Fp of the resonator moves toward the lower frequency move.
  • the equivalent Kt 2 of the resonator is reduced.
  • the dashed line of DASH is the impedance frequency characteristic curve of the equivalent circuit shown in Fig. 8. Since the equivalent inductance LE is relatively small, the series resonator point is located at a higher frequency.
  • the thin solid line is the solid line of the impedance frequency characteristic curve of the equivalent circuit shown in Fig. 9
  • the thick solid line is the insertion loss characteristic curve of the first embodiment
  • the dashed line is the insertion loss characteristic curve of the comparative example.
  • the passband edge roll-off characteristics of the embodiment are Obviously improved; at the same time, in the area shown by the dashed rectangular box in Figure 11, because the second series branch is connected across the input node P1 and the output node P2, the series resonance frequency Fs of the BAW/SAW resonator is near the The low impedance characteristic can reduce the insertion loss in the corresponding passband frequency band to the greatest extent.
  • Figure 12 is a parallel branch circuit structure diagram 501 of the comparative example, which is composed of an inductor L and a capacitor C in parallel with each other; taking the topology of the filter disclosed in Figure 7 as the second embodiment, as shown in Figure 13 It is the structure diagram 502 of the parallel branch circuit of the second embodiment (Embodiment 2), which is composed of an inductor L1 and a capacitor C1 in parallel with each other and an inductor L2 in series.
  • the thick realization represents the insertion loss characteristic curve of Embodiment 2
  • the thin solid line represents the impedance frequency characteristic curve of the parallel branch circuit in the second embodiment shown in Figure 13
  • the thick dashed line represents the insertion loss of Embodiment 1.
  • the characteristic curve, the thin dashed line is the impedance frequency characteristic curve of the parallel branch circuit of the first embodiment shown in FIG. 12. Since the inductor L2 in the parallel branch circuit of the second embodiment introduces series resonance, a suppression zero point is generated at the far band, which effectively improves the far band suppression characteristics of the filter.
  • Fig. 15 shows the change rule of the filter out-of-band suppression characteristic as the inductance of the series inductor L2 in the parallel branch changes. As the inductance of the inductor L2 increases, the suppression zero at the far band moves to the low frequency end.
  • the topology of the filter in this embodiment also includes the following implementations.
  • the first series branch includes two series resonant units in series, and each series resonant unit includes a capacitor and an inductor in series, respectively There are two L0, C2 and C3; the second series branch includes two series-connected inductors L0, and the acoustic wave resonator RES1 is connected in series between the two inductors.
  • the parallel branch includes three parallel resonant units.
  • Each parallel resonant unit includes parallel capacitors and inductances, namely C4 and L3, C5 and L4, C6 and L5.
  • the three parallel resonant units are connected in series with the input end of the branch node P1.
  • the series resonant unit connection node and the output terminal series branch node P2 are connected, the other end is connected to the inductors L6, L7, and L8 respectively, and the three inductors are grounded.
  • FIG. 17 is a schematic diagram of the topology structure of the filter provided in the fourth embodiment.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series. L0, C2, and C3;
  • the second series branch includes two series-connected inductors L0, and two sonic resonators of different frequencies are connected in series between the two inductors.
  • the two sonic resonators are connected in parallel, namely RES1 and RES2;
  • the frequencies of the resonator RES1 and the resonator RES2 are different from each other.
  • the parallel branch includes three parallel resonant units, and each parallel resonant unit includes parallel capacitors and inductances, C4 and L3, C5 and L4, C6 and L5, respectively.
  • Two parallel resonant units are connected in series with the input end of the branch node P1. Connected to the output terminal series branch node P2, the other end is connected to the inductors L6 and L8, one end of the two inductors is connected to the grounding inductor LM; one end of the other parallel resonant unit is connected to the connection node of the series resonant unit, and the other end is connected to the inductor L7, the inductor is grounded.
  • FIG. 18 is a schematic diagram of the topology structure of the filter provided in the fifth embodiment.
  • the first series branch includes two series-connected inductors L0, and two series-connected inductances are connected in series with two acoustic resonances of different frequencies.
  • RES1 and RES2 the two acoustic resonators are connected in series;
  • the second series branch includes two series inductors L0, and a series capacitor C1 between the two inductors;
  • the parallel branch includes three parallel resonant units.
  • Each parallel resonant unit includes parallel capacitors and inductances, C4 and L3, C5 and L4, C6 and L5.
  • Two parallel resonant units are connected in series with the input end of the branch node P1 and output respectively.
  • the end series branch node P2 is connected, and the other end is connected to the inductors L6 and L8 respectively.
  • One end of the two inductors is connected to the grounding inductor LM; one end of the other parallel resonance unit is connected to the connection node between the acoustic wave resonator, and the other end is connected Inductance L7, this inductance is grounded.
  • the capacitor in the series unit of the first series branch is replaced by the acoustic wave resonator RES1 and the resonator RES2 to improve the roll-off characteristics on the right side of the passband of the filter.
  • FIG. 19 is a schematic diagram of the topology structure of the filter provided in the sixth embodiment.
  • the first series branch includes two series resonant units connected in series, and each series resonant unit includes a capacitor and an inductor connected in series.
  • the second series branch includes two series-connected inductors L0, and the acoustic wave resonator RES1 is connected in series between the two inductors.
  • the parallel branch includes three parallel resonant units, and each parallel resonant unit includes parallel acoustic resonators and inductors, which are RES2 and L3, RES3 and L4, RES4 and L5, respectively.
  • Two parallel resonant units are connected in series with the input end.
  • the node P1 is connected to the output terminal series branch node P2, and the other ends are respectively connected to the inductors L6 and L8.
  • One end of the two inductors is commonly connected to the grounding inductor LM; one end of the other parallel resonant unit is connected to the connection node of the series resonant unit, and the other end Connect inductor L7, which is grounded.
  • the capacitor in the parallel resonant unit is replaced by BAW/SAW resonators, resonator RES2, resonator RES3, and resonator RES4.
  • the resonator frequencies of these two resonators are different from each other to improve the filter passband. Roll-off feature on the left.
  • the first series branch includes two series resonant units in series, each series resonant unit includes a capacitor and an inductor in series, two There are two inductors L0, C2, and C3; the second series branch includes two inductors L0 connected in series, and the acoustic wave resonator RES1 is connected in series between the two inductors.
  • the parallel branch includes three parallel resonant units.
  • Each parallel resonant unit includes parallel capacitors and inductances, C4 and L3, C5 and L4, C6 and L5.
  • One end of the three parallel resonant units is connected to the input end of the series branch.
  • the circuit node P1, the series resonant unit connection node and the output terminal series branch node P2, the other end is connected to the inductors L6, L7, and L8 respectively; wherein, the inductance L7 connected to the parallel resonant unit connected to the series resonant unit connection node is grounded,
  • the inductances L6 and L8 connected to the other two parallel resonant units are respectively connected to the ground inductance LM, and the nodes P3 and P6 between the two inductances L6 and L8 and the ground inductance LM are connected through the first inductance L9.
  • a coupling structure is added to the parallel branch of the input series branch node P1 and the output series branch node P2, such as the inductive coupling M shown in FIG. 16.
  • the inductive coupling M can improve the filter's far-band suppression characteristics .
  • an inductive coupling M is added between the series inductance L6 of the parallel branch at the input end and the series inductance L8 of the parallel branch at the output end.
  • the size of the inductive coupling M corresponds to the insertion loss characteristic curve of the second embodiment.
  • the combined suppression zero points after coupling are separated into two high and low frequency suppression zero points. The greater the amount of inductive coupling, the farther the two suppression zero points are apart.
  • the filter can be implemented by LTCC, discrete devices, IPD or other forms.
  • it is implemented by LTCC, which has the advantages of low cost, good performance, and high reliability.
  • FIG. 22 it is a schematic diagram 800 of the three-dimensional structure implemented based on LTCC in the second embodiment, where 86 is the reference plane, 80 is the resonator RES1 of the second series branch, 83 is the LTCC dielectric material, and 81 is the input terminal of the device.
  • P1 corresponds to node P4 in the circuit diagram of the second embodiment
  • P2 corresponds to node P5 in the circuit diagram of the second embodiment
  • the distance S between node P1 and node P2 corresponds to the series inductance in the parallel branch
  • the larger the S the lower the frequency of the position where the far-band suppression zero is located.
  • the parameter H corresponds to the inductance LM in the second embodiment. The larger the H, the series inductance L6 of the parallel branch at the input end and the parallel branch at the output end are connected in series. The greater the inductance coupling M is added between the inductors L8, the farther the distance between the two suppression zero points is at this time.
  • This embodiment also provides a duplexer, a high-frequency front-end circuit, and a communication device, including one or more filters in the foregoing embodiments.

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Abstract

一种滤波器、双工器、高频前端电路及通信装置，该滤波器，包括位于该滤波器的输入端和输出端之间的第一串联支路以及多个并联支路；并联支路一端位于第一串联支路上，另一端接地，滤波器还包括至少一条位于该滤波器的输入端和输出端之间的第二串联支路，该第二串联支路中包含电感（L0）；并且对于第一串联支路和第二串联支路构成的整体，该整体中存在至少1个声波谐振器（RES1），该声波谐振器（RES1）与其所在串联支路中的电感（L0）串联。所述的滤波器，有助于改善滤波器滚降特性，减小谐振器串联谐振频点附近的插损特性，以及改善滤波器远带抑制特性。

Description

一种滤波器、双工器、高频前端电路及通信装置 技术领域
本发明涉及滤波器技术领域，特别地涉及一种滤波器、双工器、高频前端电路及通信装置。
背景技术
随着无线通讯应用的发展，人们对于数据传输速率的要求越来越高，与数据传输速率相对应的是频谱资源的高利用率和频谱的复杂化。通信协议的复杂化对于射频系统的各种性能提出了严格的要求，在射频前端模块，射频滤波器起着至关重要的作用，它可以将带外干扰和噪声滤除，以满足射频系统和通信协议对于信噪比的要求。
射频滤波器主要应用于无线通信系统，例如，基站的射频前端，移动电话，电脑，卫星通讯，雷达，电子对抗系统等等。射频滤波器的主要性能指标为插损、带外抑制、功率容量、线性度、器件尺寸和成本。良好的滤波器性能可以在一定程度上提高通信系统的数据传输速率、寿命及可靠性。所以对于无线通信系统高性能、简单化滤波器的设计是至关重要的。目前，能够满足通讯终端使用的小尺寸滤波类器件主要是压电声波滤波器，构成此类声波滤波器的谐振器主要包括：FBAR(Film Bulk Acoustic Resonator，薄膜体声波谐振器)，SMR(Solidly Mounted Resonator，固态装配谐振器)和SAW(Surface Acoustic Wave，表面声波谐振器)。其中基于体声波原理FBAR和SMR制造的滤波器(统称为BAW，体声波谐振器)，相比基于表面声波原理SAW制造的滤波器，具有更低的插入损耗，更快的滚降特性等优势。
宽带滤波器一般使用LC滤波器来实现，低温共烧陶瓷(LTCC)材料由于其具有成本低、性能好、可靠性高等多种优点，被广泛应用于LC滤波器中。但是，由于LTCC的Q值的限制，其在插损、带外抑制和滚降上性能一般；同时LTCC由于侧壁电感(lead-Inductor)的存在，远带抑制特性比较差。
发明内容
有鉴于此，本发明的主要目的是提供一种滤波器、双工器、高频前端电路及通信装置，有助于改善滤波器滚降特性，减小谐振器串联谐振频点附近的插损特性，以及改善滤波器远带抑制特性。
为实现上述目的，根据本发明的一个方面，提供了一种滤波器，包括位于该滤波器的输入端和输出端之间的第一串联支路以及多个并联支路；所述并联支路一端位于所述第一串联支路上，另一端接地，所述滤波器还包括至少一条位于该滤波器的输入端和输出端之间的第二串联支路，该第二串联支路中包含电感；并且对于所述第一串联支路和第二串联支路构成的整体，该整体中存在至少1个声波谐振器，该声波谐振器与其所在串联支路中的电感串联。
可选地，第一串联支路包括两个串联的电感，两个电感之间串联电容；第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；并联支路包括两个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感。
可选地，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，三个并联谐振单元分别与输入端串联支路节点、串联谐振单元连接节点以及输出端串联支路节点连接，另一端接地。
可选地，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；并联支路包括三个并联谐振单元，每 个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感，该电感接地。
可选地，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，三个并联谐振单元分别与输入端串联支路节点、串联谐振单元连接节点以及输出端串联支路节点连接，另一端分别连接电感，该三个电感接地。
可选地，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；第二串联支路包括两个串联的电感，两个电感之间串联两个不同频率的声波谐振器，该两个声波谐振器并联；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感，该电感接地。
可选地，第一串联支路包括两个串联的电感，两个电感之间串联有两个不同频率的声波谐振器，该两个声波谐振器串联；第二串联支路包括两个串联的电感，两个电感之间串联电容；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与声波谐振器之间的连接节点连接，另一端连接电感，该电感接地。
可选地，第一串联支路包括两个串联的串联谐振单元，每个串联 谐振单元包括串联的电容和电感；第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的声波谐振器和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感，该电感接地。
第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，三个并联谐振单元的一端分别连接在输入端串联支路节点、串联谐振单元连接节点和输出端串联支路节点上，另一端分别连接电感；其中，与串联谐振单元连接节点连接的并联谐振单元所连接的电感接地，另外两个并联谐振单元所连接的电感分别连接接地电感，且该两个电感与接地电感之间的节点通过第一电感连接。
可选地，与输入端串联支路节点和输出端串联支路节点连接的两个并联谐振单元所连接的两个电感之间互感形成耦合结构。
根据本发明另一个方面，提供了一种双工器，包括上述滤波器。
本发明又一个方面，提供一种高频前端电路，包括上述滤波器。
根据本发明再一个方面，提供了一种通信装置，包括上述滤波器。
本发明取得的有益效果为：
(1)在输入端串联支路节点与输出端串联支路节点之间的第一串联支路或第二串联支路上设置声波谐振器，利用声波谐振器的高Q特性，保证Fs和Fp之间的区域用于形成滤波器的快速滚降沿，有效改 善滤波器滚降特性；
(2)利用声波谐振器的串联谐振频率Fs附近的低阻抗特性，最大程度上提升滤波器在谐振器Fs附近的插损特性；
(3)在并联支路引入串联电感在远带处形成串联谐振，并且在引入的串联电感之间加入耦合，有效改善滤波器的远带抑制特性，在很大程度上增加了设计灵活性。
附图说明
为了说明而非限制的目的，现在将根据本发明的优选实施例、特别是参考附图来描述本发明，其中：
图1a是压电声波谐振器的电学符号；
图1b是压电声波谐振器等效电学模型图；
图2是谐振器阻抗与fs和fp之间的关系；
图3是体声波谐振器结构的切面示意图；
图4是对比例的电路结构图；
图5是本实施方式提供的滤波器的拓扑结构示意图；
图6是本实施方式提供的第一实施例的拓扑结构示意图；
图7是本实施方式提供的第二实施例的拓扑结构示意图；
图8是对比例电路结构不考虑并联支路条件下串联支路的等效电路图；
图9是第一实施例电路结构在不考虑并联支路条件下的等效电路图；
图10是声波谐振器的阻抗频率特性及对比例串联支路400与第一实施例串联支路401的阻抗频率特性对比图；
图11是第一实施例与第二实施例的滚降特性对比；
图12是对比例的并联支路电路结构图；
图13是第二实施例并联支路电路结构图；
图14为第一实施例和第二实施例的远带抑制特性对比图；
图15是M＝0时，第二实施例中不同并联支路串联电感值对应的带外抑制特性；
图16是第三实施例的提供的滤波器的拓扑结构示意图；
图17是第四实施例的提供的滤波器的拓扑结构示意图；
图18是第五实施例的提供的滤波器的拓扑结构示意图；
图19是第六实施例的提供的滤波器的拓扑结构示意图；
图20是第七实施例的提供的滤波器的拓扑结构示意图；
图21是并联支路串联电感值等于0.15nH时，不同电感耦合M对应的带外抑制特性；
图22是第二实施例的三维电路模型。
具体实施方式
图1a是压电声波谐振器的电学符号，图1b是其等效电学模型图，在不考虑损耗项的情况下，电学模型简化为Lm、Cm和C0组成的谐振电路。根据谐振条件可知，该谐振电路存在两个谐振频点：一个是谐振电路阻抗值达到极小值时的fs，将fs定义为该谐振器的串联谐振频点；另一个是当谐振电路阻抗值达到极大值时的fp，将fp定义为该谐振器的并联谐振频点。其中，
Figure PCTCN2020140941-appb-000001
并且，fs比fp要小；同时，定义了谐振器的有效机电耦合系数Kt 2eff(以下简记为Kt 2)，它可以用fs和fp来表示：
Figure PCTCN2020140941-appb-000002
图2是谐振器阻抗与fs和fp之间的关系。在某一特定的频率下，有效机电耦合系数越大，则fs和fp的频率差越大，即两个谐振频点离得越远，大Kt 2谐振器可以满足宽带宽滤波器的设计需求。同时，将谐振器在fs处的阻抗幅值定义为Rs，它是谐振器阻抗曲线中的极小值；将谐振器在fp处的阻抗幅值定义为Rp，它是谐振器阻抗曲线中的极大值。Rs和Rp是描述谐振损耗特性的重要参数，当Rs越小，Rp越大时， 谐振器的损耗越小，Q值越高，此时滤波器的插入损耗特性也更好。
图3是薄膜体声波谐振器结构的切面示意图，61是半导体衬底材料，65是通过刻蚀得到的空气腔，薄膜体声波谐振器的底电极63淀积于半导体衬底61之上，62为压电薄膜材料，64为顶电极。虚线框选区域为65空气腔、64顶电极、63底电极和62压电层的重叠区域为有效谐振区。其中，顶电极和底电极的材料可以由金(Au)、钨(W)、钼(Mo)、铂(Pt)、钌(Ru)、铱(Ir)、钛钨(TiW)、铝(Al)、钛(Ti)等类似金属形成；压电层的材料可以为氮化铝(AlN)、氧化锌(ZnO)、锆钛酸铅(PZT)、铌酸锂(LiNbO3)、石英(Quartz)、铌酸钾(KNbO3)或钽酸锂(LiTaO3)等。压电薄膜的厚度一般小于10微米。氮化铝薄膜为多晶形态或者单晶形态，生长方式为薄膜溅射(sputtering)或者有机金属化学气相沉积法(MOCVD)。
图4为现有的LC滤波器100的电路结构图(对比例)，如图4所示，输入端串联支路节点P1与输出端串联支路节点P2之间设有两个串联的电容，分别为C1和C2，输入端串联支路节点P1与输入端T1之间设有电感L1，输出端串联支路节点P2与输出端T2之间设有电感L2，输入端串联支路节点P1、电容C1和C2之间的线路上、以及输出端串联支路节点P2分别连接并联支路，并联支路包括如图所示的并联的电容C3和电感L3、并联的电容C4和电感L4、并联的电容C5和电感L5，三个并联支路的另一端接地。
现有的LC滤波器，由于LTCC的Q值的限制，其插损、带外抑制和滚降等性能一般，同时LTCC由于侧壁电感(lead-Inductor)的存在，远带抑制特性比较差。
针对上述对比例中的存在的缺陷，本实施例提出一种新的滤波器，其在现有滤波器的基础上增加一条串联支路，并在任一条串联支路上设置声波滤波器形成组合型的滤波器。
图5为本实施方式提供的滤波器的拓扑结构示意图，如图5所示，第一串联支路包括两个串联的电感L0，两个电感L0之间串联电容C1；第二串联支路包括两个串联的电感L0，两个电感L0之间串联声波谐振器RES1；并联支路包括两个并联谐振单元，每个并联谐振单元包括并联的电容和电感，图中的C2、C3、L3、L4，两个并联谐振单元分别与输入端串联支路节点P1和输出端串联支路节点P2连接，另一端分别连接电感L5、L6，该两个电感L5、L6的一端共同(节点P3)连接接地电感LM。此结构中并联支路包括两个并联谐振单元，其中，滤波器还可包括三个并联谐振单元，图6为本实施方式提供的另一种结构的滤波器的拓扑结构示意图；图中，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感，图中的C2、C3及与其连接的L0；第二串联支路包括两个串联的电感L0，两个电感L0之间串联声波谐振器RES1；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，如图中并联的C4和L3、C5和L4、C6和L5；三个并联谐振单元分别与输入端串联支路节点P1、串联谐振单元连接节点以及输出端串联支路节点P2连接，另一端接地。
如图7所示，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感，分别为两个L0、C2和C3；第二串联支路包括两个串联的电感L0，两个电感之间串联声波谐振器RES1；并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，分别为并联的C4和L3、C5和L4、以及C6和L5，两个并联谐振单元分别与输入端串联支路节点P1和输出端串联支路节点P2连接，另一端分别连接电感L6和L8，该两个电感的一端共同连接接地电感LM；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感L7，该电感接地。
如图8所示为对比例电路结构100不考虑并联支路条件下串联支路的等效电路图400，其中电感器LE为串联支路的等效电感，电容器CE为串联支路的等效电容。以图6中公开的滤波器的拓扑结构为第一实施例(实施例1)，图9所示为第一实施例电路结构300在不考虑并 联支路条件下的等效电路图401，其中电感LE为串联支路的等效电感，电容CE为串联支路的等效电容，2L0代表输入输出端的串联电感。
如图10所示，其中实线为图9中谐振器RES的阻抗频率特性曲线，DOT虚线为图9所示等效电路的阻抗频率特性曲线，谐振器RES串联等效电感后谐振器的串联谐振器频率Fs向低频端移动，由于串联等效电感比较小，所以401等效电路的串联谐振频率Fs几乎不变，谐振器RES并联等效电容后谐振器的并联谐振器频率Fp向低频段移动。综上，由于401所示等效电路中等效电感和等效电容的引入使得谐振器的等效Kt 2减小。DASH虚线为图8所示等效电路的阻抗频率特性曲线，由于等效电感LE比较小，所以串联谐振器点位于较高频处。
如图11所示，其中细实线为图9所示等效电路的阻抗频率特性曲线实线，粗实线为第一实施例的插损特性曲线，虚线为对比例的插损特性曲线，由于BAW/SAW谐振器(声波谐振器)的高Q特性，保证Fs和Fp之间的区域用于形成滤波器的快速滚降沿，所以相对于对比例，实施例的通带边缘滚降特性得到明显改善；同时，如图11中虚线矩形框所示区域，由于第二串联支路跨接在输入端节点P1和输出端节点P2之间，BAW/SAW谐振器的串联谐振频率Fs附近的低阻抗特性可以在最大程度上减小对应通带频带范围内的插损。
如图12所示为对比例的并联支路电路结构图501，由电感器L和电容器C相互并联组成；以图7中公开的滤波器的拓扑结构为第二实施例，如图13所示为第二实施例(实施例2)并联支路电路结构图502，由电感器L1和电容器C1相互并联再与一个电感器L2串联组成。
如图14所示，其中粗实现代表实施例2的插损特性曲线，细实线代表图13所示第二实施例中并联支路电路阻抗频率特性曲线；粗虚线为实施例1的插损特性曲线，细虚线为图12所示第一实施例的并联支路电路阻抗频率特性曲线。由于第二实施例并联支路电路中电感器L2引入串联谐振，在远带处产生一个抑制零点，有效改善了滤波器的远 带抑制特性。
如图15所示，示出了随着并联支路中串联电感器L2电感量的变化，滤波器带外抑制特性的变化规律。随着电感器L2电感量的增大，远带处的抑制零点向低频端移动。
除上述第一实施例和第二实施例外，本实施例中有关滤波器的拓扑结构还包括如下实施方式。
图16为第三实施例的提供的滤波器的拓扑结构示意图，如图16所示，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感，分别为两个L0、C2和C3；第二串联支路包括两个串联的电感L0，两个电感之间串联声波谐振器RES1。
并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，分别为C4和L3、C5和L4、C6和L5，三个并联谐振单元分别与输入端串联支路节点P1、串联谐振单元连接节点以及输出端串联支路节点P2连接，另一端分别连接电感L6、L7和L8，该三个电感接地。
图17为第四实施例的提供的滤波器的拓扑结构示意图，如图17所示，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感，两个L0、C2和C3；第二串联支路包括两个串联的电感L0，两个电感之间串联两个不同频率的声波谐振器，该两个声波谐振器并联，为RES1和RES2；其中，谐振器RES1和谐振器RES2的频率彼此不同。
并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，分别为C4和L3、C5和L4、C6和L5，两个并联谐振单元分别与输入端串联支路节点P1和输出端串联支路节点P2连接，另一端分别连接电感L6和L8，该两个电感的一端共同连接接地电感LM； 另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感L7，该电感接地。
图18为第五实施例的提供的滤波器的拓扑结构示意图，如图18所示，第一串联支路包括两个串联的电感L0，两个电感之间串联有两个不同频率的声波谐振器，RES1和RES2，该两个声波谐振器串联；第二串联支路包括两个串联的电感L0，两个电感之间串联电容C1；
并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，C4和L3、C5和L4、C6和L5，两个并联谐振单元分别与输入端串联支路节点P1和输出端串联支路节点P2连接，另一端分别连接电感L6和L8，该两个电感的一端共同连接接地电感LM；另一个并联谐振单元的一端与声波谐振器之间的连接节点连接，另一端连接电感L7，该电感接地。本实施例中，第一串联支路串联单元中的电容由声波谐振器RES1和谐振器RES2替代，改善滤波器通带右侧的滚降特性。
图19为第六实施例的提供的滤波器的拓扑结构示意图，如图19所示，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感，两个L0、C2和C3；第二串联支路包括两个串联的电感L0，两个电感之间串联声波谐振器RES1。
并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的声波谐振器和电感，分别为RES2和L3、RES3和L4、RES4和L5，两个并联谐振单元分别与输入端串联支路节点P1和输出端串联支路节点P2连接，另一端分别连接电感L6和L8，该两个电感的一端共同连接接地电感LM；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感L7，该电感接地。该实施例中，并联谐振单元中的电容由BAW/SAW谐振器替代，谐振器RES2、谐振器RES3和谐振器RES4，这两个谐振器的谐振器频率彼此不同，用来改善滤波器通带左侧的滚降特性。
图20是第七实施例的提供的滤波器的拓扑结构示意图；如图20所示，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感，两个电感L0、C2和C3；第二串联支路包括两个串联的电感L0，两个电感之间串联声波谐振器RES1。
并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，分别为C4和L3、C5和L4、C6和L5，三个并联谐振单元的一端分别连接在输入端串联支路节点P1、串联谐振单元连接节点和输出端串联支路节点P2上，另一端分别连接电感L6、L7和L8；其中，与串联谐振单元连接节点连接的并联谐振单元所连接的电感L7接地，另外两个并联谐振单元所连接的电感L6和L8分别连接接地电感LM，且该两个电感L6和L8与接地电感LM之间的节点P3和P6通过第一电感L9连接。
本实施例中，输入端串联支路节点P1与输出端串联支路节点P2的并联支路上加入耦合结构，如图16中所示的电感耦合M，电感耦合M可以改善滤波器远带抑制特性。以第二实施例为例，输入端并联支路的串联电感L6与输出端并联支路的串联电感L8之间加入电感耦合M，电感耦合M的大小对应第二实施例的插损特性曲线，如图21所示，加入耦合后合并的抑制零点彼此分开成高低频的两个抑制零点，电感耦合量越大，这两个抑制零点相距越远。综上，通过改变电感器L2电感量以及输入端并联支路的串联电感L6与输出端并联支路的串联电感L8之间加入电感耦合量，可以满足不同频段带外抑制指标需求，在很大程度上增加了设计的灵活度。
在本实施例中，滤波器可以通过LTCC，分立器件，IPD或者其他形式实现，优选地，采用LTCC实现，LTCC具有成本低、性能好、可靠性高等优点。如图22所示，为第二实施例基于LTCC实现的三维结构示意图800，其中86为参考平面，80为第二串联支路的谐振器RES1，83为LTCC介质材料，81为器件输入端子，82为器件的输出端子，P1 对应第二实施例电路图中的节点P4，P2对应第二实施例电路图中的节点P5，节点P1与节点P2之间的距离S对应并联支路中的串联电感，S越大产生的远带抑制零点所在的位置频率越低，参数H对应第二实施例中的电感LM，H越大，代表输入端并联支路的串联电感L6与输出端并联支路的串联电感L8之间加入电感耦合M越大，此时这两个抑制零点相距越远。
本实施例还提供一种双工器、高频前端电路及通信装置，包括一个或多个上述实施例中的滤波器。
上述具体实施方式，并不构成对本发明保护范围的限制。本领域技术人员应该明白的是，取决于设计要求和其他因素，可以发生各种各样的修改、组合、子组合和替代。任何在本发明的精神和原则之内所作的修改、等同替换和改进等，均应包含在本发明保护范围之内。

Claims (13)

  1. 一种滤波器，包括位于该滤波器的输入端和输出端之间的第一串联支路以及多个并联支路；所述并联支路一端位于所述第一串联支路上，另一端接地，其特征在于，
    所述滤波器还包括至少一条位于该滤波器的输入端和输出端之间的第二串联支路，该第二串联支路中包含电感；
    并且对于所述第一串联支路和第二串联支路构成的整体，该整体中存在至少1个声波谐振器，该声波谐振器与其所在串联支路中的电感串联。
  2. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的电感，两个电感之间串联电容；
    第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
    并联支路包括两个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感。
  3. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
    第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，三个并联谐振单元分别与输入端串联支路节点、串联谐振单元连接节点以及输出端串联支路节点连接，另一端接地。
  4. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包 括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
    第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感，该电感接地。
  5. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
    第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，三个并联谐振单元分别与输入端串联支路节点、串联谐振单元连接节点以及输出端串联支路节点连接，另一端分别连接电感，该三个电感接地。
  6. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
    第二串联支路包括两个串联的电感，两个电感之间串联两个不同频率的声波谐振器，该两个声波谐振器并联；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感，该电感接地。
  7. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的电感，两个电感之间串联有两个不同频率的声波谐振器，该两个声波谐振器串联；
    第二串联支路包括两个串联的电感，两个电感之间串联电容；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与声波谐振器之间的连接节点连接，另一端连接电感，该电感接地。
  8. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
    第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的声波谐振器和电感，两个并联谐振单元分别与输入端串联支路节点和输出端串联支路节点连接，另一端分别连接电感，该两个电感的一端共同连接接地电感；另一个并联谐振单元的一端与串联谐振单元连接节点连接，另一端连接电感，该电感接地。
  9. 根据权利要求1所述的滤波器，其特征在于，第一串联支路包括两个串联的串联谐振单元，每个串联谐振单元包括串联的电容和电感；
    第二串联支路包括两个串联的电感，两个电感之间串联声波谐振器；
    并联支路包括三个并联谐振单元，每个并联谐振单元包括并联的电容和电感，三个并联谐振单元的一端分别连接在输入端串联支路节点、串联谐振单元连接节点和输出端串联支路节点上，另一端分别连 接电感；其中，与串联谐振单元连接节点连接的并联谐振单元所连接的电感接地，另外两个并联谐振单元所连接的电感分别连接接地电感，且该两个电感与接地电感之间的节点通过第一电感连接。
  10. 根据权利要求2或4至9中任一项所述的滤波器，其特征在于，与输入端串联支路节点和输出端串联支路节点连接的两个并联谐振单元所连接的两个电感之间互感形成耦合结构。
  11. 一种双工器，其特征在于，包括如权利要求1至10中任一项所述的滤波器。
  12. 一种高频前端电路，其特征在于，包括如权利要求1至10中任一项所述的滤波器。
  13. 一种通信装置，其特征在于，包括如权利要求1至10中任一项所述的滤波器。
PCT/CN2020/140941 2020-01-16 2020-12-29 一种滤波器、双工器、高频前端电路及通信装置 WO2021143520A1 (zh)

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CN112073018B (zh) * 2020-05-28 2022-02-25 诺思(天津)微系统有限责任公司 双工器、多工器以及通信设备
CN111641488B (zh) * 2020-05-28 2022-08-05 苏州汉天下电子有限公司 双工器
CN112350684B (zh) * 2020-10-29 2021-08-10 诺思(天津)微系统有限责任公司 一种声波滤波器、多工器、通信设备
CN112688660B (zh) * 2020-11-27 2023-02-03 中国电子科技集团公司第十三研究所 Fbar滤波器电路
CN113098423A (zh) * 2021-04-16 2021-07-09 苏州汉天下电子有限公司 一种lc滤波器
CN114465601B (zh) * 2022-04-13 2022-08-12 苏州汉天下电子有限公司 一种滤波器、双工器以及多工器
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