multiplexer

Abstract

Suppressing IMD generation. In each filter (3), the current flowing through the series circuit containing the equivalent resistance, equivalent inductor and equivalent capacitance in the equivalent circuit of a specific resonator (4A) is set as the acoustic path current, and the phase of the acoustic path current on the common terminal (2) side of the first transmitting filter (31) at the frequency in the first passband is set as θ1. Tx1 The phase of the acoustic path current on the common terminal (2) side of the first transmitting filter (31) at the frequency within the second passband is set to θ2. Tx1 The phase of the acoustic path current on the common terminal (2) side of the second transmitting filter (33) at the frequency within the first passband is set to θ1. Tx2 The phase of the acoustic path current on the common terminal (2) side of the second transmitting filter (33) at the frequency within the second passband is set to θ2. Tx2 In this case, the multiplexer (1) satisfies the first condition: |(2·θ1) Tx1 -θ2 Tx1 )-(2·θ1 Tx2 -θ2 Tx2 )|=180°±90°, or the second condition: |(2·θ2) Tx1 -θ1 Tx1 )-(2·θ2 Tx2 -θ1 Tx2 )|=180°±90°.

Description

Technical Field

[0001] The present invention generally relates to multiplexers, and more specifically to a multiplexer having a first transmit filter and a second transmit filter. Background Technology

[0002] Previously, multiplexers with multiple frequency bands for transmitting and receiving filters were known (for example, see Patent Document 1).

[0003] The multiplexer described in Patent Document 1 includes multiple filters (a first transmit filter, a first receive filter, a second transmit filter, and a second receive filter) with different frequency bands. The first transmit filter, the first receive filter, the second transmit filter, and the second receive filter are connected to a common terminal connected to an antenna. The first transmit filter is, for example, a transmit filter using the transmit band (1710MHz-1785MHz) of Band 3 of the LTE (Long Term Evolution) standard as its passband. The first receive filter is, for example, a receive filter using the receive band (1805MHz-1880MHz) of Band 3 as its passband. The second transmit filter is, for example, a transmit filter using the transmit band (1920MHz-1980MHz) of Band 1 as its passband. The second receive filter is, for example, a receive filter using the receive band (2110MHz-2170MHz) of Band 1 as its passband. Each of the multiple filters is constructed as a trapezoidal filter, each having parallel-arm resonators and series-arm resonators.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2018 / 123545 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] A communication device equipped with the multiplexer described in Patent Document 1 can handle carrier aggregation (dual uplink carrier aggregation) that uses two frequency bands simultaneously in the uplink. However, if the multiplexer described in Patent Document 1 is used in a communication device to perform dual uplink carrier aggregation that simultaneously transmits two signals with different frequency bands, there is a concern that IMD (Intermodulation Distortion) may occur, which could degrade the receiving sensitivity of the receiving filter.

[0009] The purpose of this invention is to provide a multiplexer capable of suppressing the generation of IMD.

[0010] Technical solutions for solving the problem

[0011] One aspect of the present invention relates to a multiplexer comprising a common terminal and a plurality of filters. The plurality of filters are connected to the common terminal. Each of the plurality of filters has a plurality of resonators. The plurality of filters includes a first transmitting filter and a second transmitting filter. The first transmitting filter has a first passband. The second transmitting filter has a second passband different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. In the multiplexer, when the equivalent circuit of a particular resonator among the plurality of resonators in each of the plurality of filters is represented by a series circuit of equivalent resistance, equivalent inductance, and equivalent capacitance, and a parallel circuit of damping capacitance, if the current flowing through the series circuit is defined as the acoustic path current, then the phase of the acoustic path current at the common terminal side of the first transmitting filter at a frequency within the first passband is defined as θ1. Tx1 The phase of the acoustic path current on the common terminal side of the first transmitting filter at the frequency within the second passband is set to θ2. Tx1 The phase of the acoustic path current on the common terminal side of the second transmitting filter at the frequency within the first passband is set to θ1. Tx2 The phase of the acoustic path current on the common terminal side of the second transmitting filter at the frequency within the second passband is set to θ2. Tx2 In this case, the multiplexer satisfies either condition 1 or condition 2. Condition 1 is as follows: |(2·θ1) Tx1 -θ2 Tx1 )-(2·θ1 Tx2 -θ2 Tx2 |=180°±90°. The second condition is as follows: |(2·θ2) Tx1 -θ1 Tx1 )-(2·θ2 Tx2 -θ1 Tx2 )|=180°±90°.

[0012] One aspect of the present invention relates to a multiplexer comprising a common terminal and a plurality of filters. The plurality of filters are connected to the common terminal. Each of the plurality of filters has a plurality of resonators. The plurality of filters includes a first transmitting filter and a second transmitting filter. The first transmitting filter has a first passband. The second transmitting filter has a second passband different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. In each of the plurality of filters, the resonator closest to the common terminal is designated as a specific resonator. Both the first and second transmitting filters are trapezoidal filters and include a plurality of series-arm resonators and a plurality of parallel-arm resonators as the plurality of resonators. In the first transmitting filter, the specific resonator is one of the parallel-arm resonators of the first transmitting filter, and in the second transmitting filter, the specific resonator is one of the series-arm resonators of the second transmitting filter. In the multiplexer, the damping capacitance of a specific resonator in the first transmitting filter is greater than the damping capacitance of a specific resonator in the second transmitting filter. Alternatively, in the multiplexer, the area of ​​a specific resonator in the first transmitting filter is greater than the area of ​​a specific resonator in the second transmitting filter. Alternatively, in the multiplexer, the number of multiple segmented resonators included in and connected in series with the specific resonator in the first transmitting filter is greater than the number of multiple segmented resonators included in and connected in series with the specific resonator in the second transmitting filter. Alternatively, in the multiplexer, each of the multiple resonators in the first transmitting filter has an IDT electrode, and each of the multiple resonators in the second transmitting filter has an IDT electrode, the duty cycle of the IDT electrode of the specific resonator in the first transmitting filter being different from the duty cycle of the IDT electrode of the specific resonator in the second transmitting filter. Alternatively, in the multiplexer, each of the plurality of resonators of the first transmitting filter has an IDT electrode, and each of the plurality of resonators of the second transmitting filter has an IDT electrode, wherein the thickness of the IDT electrode in the particular resonator of the first transmitting filter is less than the thickness of the IDT electrode in the particular resonator of the second transmitting filter. Alternatively, in the multiplexer, each of the plurality of resonators of the first transmitting filter has an IDT electrode, and each of the plurality of resonators of the second transmitting filter has an IDT electrode, wherein the IDT electrode of the particular resonator of the first transmitting filter is a polycrystalline metal electrode, and the IDT electrode of the particular resonator of the second transmitting filter is a metallic epitaxial layer electrode.Alternatively, in the multiplexer, each of the plurality of resonators of the first transmitting filter has an IDT electrode, and each of the plurality of resonators of the second transmitting filter has an IDT electrode. The material of the IDT electrode of the particular resonator of the first transmitting filter comprises one or more of Pt, Mo, Au, Ag, Cu, and W, and the content of one or more of Pt, Mo, Au, Ag, Cu, and W in the IDT electrode of the particular resonator of the first transmitting filter is higher than the content of one or more of the same material in the IDT electrode of the particular resonator of the second transmitting filter.

[0013] Invention Effects

[0014] The multiplexers described above in this invention can suppress the generation of IMD. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of the multiplexer involved in Implementation Method 1.

[0016] Figure 2 This is the circuit diagram of the filter in the same multiplexer.

[0017] Figure 3 This is the circuit diagram of the filter in the same multiplexer.

[0018] Figure 4A This is a top view of the resonator of the filter in the same multiplexer. Figure 4B yes Figure 4A A sectional view along line AA.

[0019] Figure 5 This is the equivalent circuit diagram of the resonator of the filter in the same multiplexer.

[0020] Figure 6 This is the equivalent circuit diagram of the same multiplexer.

[0021] Figure 7 This is the impedance-frequency response diagram of the resonator of the filter in the same multiplexer.

[0022] Figure 8 This is the current-frequency response diagram of the resonator of the filter in the same multiplexer.

[0023] Figure 9 This is the phase-frequency response diagram of the resonator of the filter in the same multiplexer.

[0024] Figure 10 This is the voltage-frequency response diagram of the resonator of the filter in the same multiplexer.

[0025] Figure 11AThis is a frequency response diagram of the third-order intermodulation distortion (IMD3) levels of the first and second transmitting filters in the same multiplexer. Figure 11B This is a frequency response diagram of the phase of the IMD3 of the first and second transmitting filters in the same multiplexer.

[0026] Figure 12 This is a frequency response diagram of the IMD3 level of the first and second transmitting filters in the same multiplexer.

[0027] Figure 13A This is a top view of a specific resonator in the first transmitting filter of the same multiplexer. Figure 13B This is a top view of a specific resonator in the second transmitting filter of the same multiplexer.

[0028] Figure 14A This is a top view of a specific resonator of the first transmitting filter in the multiplexer involved in a variation of embodiment 1, specifically embodiment 1. Figure 14B This is a top view of a specific resonator in the second transmitting filter of the same multiplexer.

[0029] Figure 15A This is a circuit diagram of the first transmitting filter in the multiplexer involved in a variation of embodiment 1, example 2. Figure 15B This is a top view of a specific resonator in the first transmitting filter, as described above.

[0030] Figure 16A This is the circuit diagram of the second transmitting filter in the same multiplexer. Figure 16B This is a top view of a specific resonator in the second transmitting filter, as described above.

[0031] Figure 17A This is a top view of a specific resonator of the first transmitting filter in the multiplexer involved in Variation 3 of Embodiment 1. Figure 17B This is a top view of a specific resonator in the second transmitting filter of the same multiplexer.

[0032] Figure 18A This is a cross-sectional view of a specific resonator of the first transmitting filter in the multiplexer according to Embodiment 2. Figure 18B This is a cross-sectional view of a specific resonator in the second transmitting filter of the same multiplexer.

[0033] Figure 19A This is a cross-sectional view of a specific resonator of the first transmitting filter in the multiplexer according to Embodiment 3. Figure 19BThis is an illustration of the formation method of a specific resonator for the second transmitting filter in the same multiplexer. Figure 19C This is a cross-sectional view of a specific resonator in the second transmitting filter of the same multiplexer.

[0034] Figure 20A This is a cross-sectional view of a specific resonator of the first transmitting filter in the multiplexer according to Embodiment 4. Figure 20B This is a cross-sectional view of a specific resonator in the second transmitting filter of the same multiplexer.

[0035] Figure 21 This is the circuit diagram of the multiplexer involved in Implementation Method 5. Detailed Implementation

[0036] (Implementation Method 1)

[0037] The following is for reference Figures 1-13B The multiplexer 1 involved in Implementation 1 will be described.

[0038] (1.1) Basic structure of a multiplexer

[0039] The multiplexer 1 involved in Implementation 1 is used, for example, for portable telephones (e.g., smartphones), wearable terminals (e.g., smartwatches), etc., to cope with carrier aggregation.

[0040] The multiplexer 1 has a common terminal 2 and multiple filters 3. In addition, the multiplexer 1 also has multiple phase shifting circuits 8 that correspond one-to-one with the multiple filters 3.

[0041] The plurality of filters 3 includes a first transmit filter 31 and a second transmit filter 33. The plurality of filters 3 also includes a first receive filter 32 and a second receive filter 34.

[0042] Multiple filters 3 are connected to a common terminal 2. The common terminal 2 is connected to an antenna 9. The multiple filters 3 are connected to the common terminal 2 via a one-to-one correspondence of multiple phase-shifting circuits 8. The multiple phase-shifting circuits 8 include a first phase-shifting circuit 81, a second phase-shifting circuit 83, a third phase-shifting circuit 82, and a fourth phase-shifting circuit 84. The first phase-shifting circuit 81 is connected between the common terminal 2 and the first transmitting filter 31. The second phase-shifting circuit 83 is connected between the common terminal 2 and the second transmitting filter 33. The third phase-shifting circuit 82 is connected between the common terminal 2 and the first receiving filter 32. The fourth phase-shifting circuit 84 is connected between the common terminal 2 and the second receiving filter 34. Each of the multiple filters 3 has multiple resonators 4.

[0043] The first transmitting filter 31 has an input terminal 311 and an output terminal 312. In the first transmitting filter 31, the output terminal 312 is connected to a common terminal 2. The second transmitting filter 33 has an input terminal 331 and an output terminal 332. In the second transmitting filter 33, the output terminal 332 is connected to a common terminal 2. The first receiving filter 32 has an input terminal 321 and an output terminal 322. In the first receiving filter 32, the input terminal 321 is connected to a common terminal 2. The second receiving filter 34 has an input terminal 341 and an output terminal 342. In the second receiving filter 34, the input terminal 341 is connected to a common terminal 2.

[0044] The first transmit filter 31 is a bandpass filter with a first passband. The second transmit filter 33 is a bandpass filter with a second passband different from the first passband. The first receive filter 32 is a bandpass filter with a third passband. The second receive filter 34 is a bandpass filter with a fourth passband. The center frequency of the first passband is higher than the center frequency of the second passband. The first passband is the first transmit band. The first transmit band is, for example, the uplink band (1850MHz-1915MHz) of Band 25 in the 3GPP (Third Generation Partnership Project) and LTE (Long Term Evolution) standards. The second passband is the second transmit band. The second transmit band is, for example, the uplink band (1710MHz-1780MHz) of Band 66 in the 3GPP and LTE standards. The third passband is the first receive band. The first receive band is, for example, the downlink band (1930MHz-1995MHz) of Band 25 in the 3GPP LTE standard. The fourth passband is the second receive band. The second receive band is, for example, the downlink band (2110MHz-2200MHz) of Band 66 in the 3GPP LTE standard. Furthermore, although the first transmit filter 31 is a bandpass filter with the first transmit band as its first passband, it is not limited to this; any bandpass filter that includes the first transmit band in its first passband is acceptable. Similarly, although the second transmit filter 33 is a bandpass filter with the second transmit band as its second passband, it is not limited to this; any bandpass filter that includes the second transmit band in its second passband is acceptable. Furthermore, although the first receive filter 32 is a bandpass filter with the first receive band as its third passband, it is not limited to this; any bandpass filter that includes the first receive band in its third passband is acceptable. Furthermore, although the second receiving filter 34 is a bandpass filter having a second receiving band as a fourth passband, it is not limited to this; it can be any bandpass filter having a fourth passband that includes the second receiving band.

[0045] The passbands of the multiple filters 3 do not overlap. Therefore, the first passband of the first transmitting filter 31 does not overlap with the second, third, and fourth passbands of the second transmitting filter 33, the first receiving filter 32, and the second receiving filter 34, respectively. Furthermore, the second passband of the second transmitting filter 33 does not overlap with the first, third, and fourth passbands of the first transmitting filter 31, the first receiving filter 32, and the second receiving filter 34, respectively. Similarly, the third passband of the first receiving filter 32 does not overlap with the first, second, and fourth passbands of the first transmitting filter 31, the second transmitting filter 33, and the second receiving filter 34, respectively. Finally, the fourth passband of the second receiving filter 34 does not overlap with the first, second, and third passbands of the first transmitting filter 31, the second transmitting filter 33, and the first receiving filter 32, respectively.

[0046] Multiplexer 1, for example, can simultaneously transmit the transmission signal of the first passband of the first transmit filter 31 input to the input terminal 311 of the first transmit filter 31 and the transmission signal of the second passband of the second transmit filter 33 input to the input terminal 331 of the second transmit filter 33 from the common terminal 2. That is, multiplexer 1 can handle dual uplink carrier aggregation.

[0047] The first transmitting filter 31 is, for example, a trapezoidal filter, and includes multiple (for example, four) series arm resonators S11 to S14 and multiple (for example, four) parallel arm resonators P11 to P14 as multiple (for example, eight) resonators 4.

[0048] Multiple series-arm resonators S11 to S14 are arranged on the path 310 (hereinafter also referred to as the series-arm path 310) between the input terminal 311 and the output terminal 312. The multiple series-arm resonators S11 to S14 are connected in series on the series-arm path 310. In the first transmitting filter 31, multiple series-arm resonators S11 to S14 are arranged in the order of series-arm resonator S11, series-arm resonator S12, series-arm resonator S13, and series-arm resonator S14, starting from the input terminal 311 side.

[0049] Parallel arm resonator P11 is positioned between node N11 and ground (ground terminal) on series arm path 310. Node N11 is located between series arm resonators S11 and S12 on series arm path 310. Parallel arm resonator P12 is positioned between node N12 and ground on series arm path 310. Node N12 is located between series arm resonators S12 and S13 on series arm path 310. Parallel arm resonator P13 is positioned between node N13 and ground on series arm path 310. Node N13 is located between series arm resonators S13 and S14 on series arm path 310. Parallel arm resonator P14 is positioned between node N14 and ground on series arm path 310. Node N14 is located between series arm resonator S14 and output terminal 312 on series arm path 310. In summary, in the first transmitting filter 31, a π-type filter is formed on the output terminal 312 side by two parallel arm resonators P14 and P13 and one series arm resonator S14. Therefore, in the multiplexer 1, no resonator 4 is connected between the common terminal 2 and the parallel arm resonator P14 of the first transmitting filter 31.

[0050] The second transmitting filter 33 is, for example, a trapezoidal filter, and comprises multiple (e.g., eight) series arm resonators S31 to S34 and multiple (e.g., four) parallel arm resonators P31 to P34 as multiple (e.g., eight) resonators 4.

[0051] Multiple series-arm resonators S31 to S34 are arranged on the path 330 (hereinafter also referred to as the series-arm path 330) between the input terminal 331 and the output terminal 332. The multiple series-arm resonators S31 to S34 are connected in series on the series-arm path 330. In the second transmitting filter 33, multiple series-arm resonators S31 to S34 are arranged in the order of series-arm resonator S31, series-arm resonator S32, series-arm resonator S33, and series-arm resonator S34, starting from the input terminal 331 side.

[0052] Parallel arm resonator P31 is positioned between node N31 and ground (ground terminal) on the series arm path 330. Node N31 is located between input terminal 331 and series arm resonator S31 on the series arm path 330. Parallel arm resonator P32 is positioned between node N32 and ground on the series arm path 330. Node N32 is located between series arm resonators S31 and S32 on the series arm path 330. Parallel arm resonator P33 is positioned between node N33 and ground on the series arm path 330. Node N33 is located between series arm resonators S32 and S33 on the series arm path 330. Parallel arm resonator P34 is positioned between node N34 and ground on the series arm path 330. Node N34 is located between series arm resonators S33 and S34 on the series arm path 330. In summary, in the second transmitting filter 33, a T-type filter is formed on the output terminal 332 side by two series arm resonators S34, S33 and one parallel arm resonator P34.

[0053] The first receiving filter 32 is, for example, a trapezoidal filter, and includes multiple (for example, four) series arm resonators S21 to S24 and multiple (for example, four) parallel arm resonators P21 to P24 as multiple (for example, eight) resonators 4.

[0054] Multiple series-arm resonators S21 to S24 are arranged on the path 320 (hereinafter also referred to as the series-arm path 320) between the input terminal 321 and the output terminal 322. The multiple series-arm resonators S21 to S24 are connected in series on the series-arm path 320. In the first receiving filter 32, multiple series-arm resonators S21 to S24 are arranged in the order of series-arm resonator S21, series-arm resonator S22, series-arm resonator S23, and series-arm resonator S24, starting from the output terminal 322 side.

[0055] Parallel arm resonator P21 is positioned between node N21 and ground (ground terminal) on series arm path 320. Node N21 is located between output terminal 322 and series arm resonator S21 on series arm path 320. Parallel arm resonator P22 is positioned between node N22 and ground on series arm path 320. Node N22 is located between series arm resonators S21 and S22 on series arm path 320. Parallel arm resonator P23 is positioned between node N23 and ground on series arm path 320. Node N23 is located between series arm resonators S22 and S23 on series arm path 320. Parallel arm resonator P24 is positioned between node N24 and ground on series arm path 320. Node N24 is located between series arm resonators S23 and S24 on series arm path 320. In summary, in the first receiving filter 32, a T-type filter is formed on the input terminal 321 side by two series arm resonators S24 and S23 and one parallel arm resonator P24.

[0056] The second receiving filter 34 is, for example, a trapezoidal filter, and includes multiple (for example, four) series arm resonators S41 to S44 and multiple (for example, four) parallel arm resonators P41 to P44 as multiple (for example, eight) resonators 4.

[0057] Multiple series-arm resonators S41 to S44 are arranged on the path 340 (hereinafter also referred to as the series-arm path 340) between the input terminal 341 and the output terminal 342. The multiple series-arm resonators S41 to S44 are connected in series on the series-arm path 340. In the second receiving filter 34, multiple series-arm resonators S41 to S44 are arranged in the order of series-arm resonator S41, series-arm resonator S42, series-arm resonator S43, and series-arm resonator S44, starting from the output terminal 342 side.

[0058] Parallel arm resonator P41 is positioned between node N41 and ground (ground terminal) on series arm path 340. Node N41 is located between output terminal 342 and series arm resonator S41 on series arm path 340. Parallel arm resonator P42 is positioned between node N42 and ground on series arm path 340. Node N42 is located between series arm resonators S41 and S42 on series arm path 340. Parallel arm resonator P43 is positioned between node N43 and ground on series arm path 340. Node N43 is located between series arm resonators S42 and S43 on series arm path 340. Parallel arm resonator P44 is positioned between node N44 and ground on series arm path 340. Node N44 is located between series arm resonators S43 and S44 on series arm path 340. In summary, in the second receiving filter 34, a T-type filter is formed on the input terminal 341 side by two series arm resonators S44 and S43 and one parallel arm resonator P44.

[0059] In each of the multiple filters 3, the resonator 4 closest to the common terminal 2 among the multiple resonators 4 is designated as a specific resonator 4A. In the filter 3 as follows... Figure 2 In the case of a trapezoidal filter where a π-type filter is formed on the common terminal 2 side, the specific resonator 4A is set as the parallel arm resonator closest to the common terminal 2. Furthermore, when the filter 3 is as shown... Figure 3 In the case of a trapezoidal filter in which a T-type filter is formed on the side of the common terminal 2, the specific resonator 4A is set as the series arm resonator closest to the common terminal 2.

[0060] (1.2) Filter Construction

[0061] Each of the multiple filters 3 is, for example, an elastic wave filter, and each of the multiple resonators 4 is composed of an elastic wave resonator. The elastic wave filter is, for example, a SAW (Surface Acoustic Wave) filter utilizing surface acoustic waves. In this case, each of the multiple resonators 4 is a SAW resonator.

[0062] The following is based on Figure 4A And an example of the construction of filter 3 by 4B is given.

[0063] The filter 3 includes a piezoelectric substrate 40 and multiple IDT (Interdigital Transducer) electrodes 50 disposed on the piezoelectric substrate 40. Additionally, in Figure 4AIn 4B, only one of the multiple IDT electrodes 50 is shown. Each of the multiple IDT electrodes 50 corresponds one-to-one with a multiple resonator 4. Each of the multiple IDT electrodes 50 is a component of its corresponding resonator 4. The filter 3 is, for example, a monolithic elastic wave filter, composed of multiple series-arm resonators and multiple parallel-arm resonators, each a separate elastic wave resonator.

[0064] The piezoelectric substrate 40 is, for example, a piezoelectric substrate. The material of the piezoelectric substrate is, for example, lithium tantalate (LiTaO3). The piezoelectric substrate is, for example, formed from a Γ°Y-cut X-propagating LiTaO3 piezoelectric single crystal. The Γ°Y-cut X-propagating LiTaO3 piezoelectric single crystal is a LiTaO3 single crystal that has been cut by rotating an axis Γ° from the Y-axis to the Z-axis with the X-axis as the central axis, with the three crystal axes of the LiTaO3 piezoelectric single crystal set as the X-axis, Y-axis, and Z-axis, and is a single crystal in which surface acoustic waves propagate in the X-axis direction. If the cutting angle is set to Γ [°], and the Euler angle of the piezoelectric substrate is set to... The cutting angle of the piezoelectric substrate is then θ = Γ + 90°. Here, Γ and F ± 180 × n are synonymous. n is a natural number. The piezoelectric substrate is not limited to a Γ°Y-cut X-propagated LiTaO3 piezoelectric single crystal; for example, it can also be a Γ°Y-cut X-propagated LiTaO3 piezoelectric ceramic.

[0065] The piezoelectric substrate 40 has a first main surface 41 and a second main surface 42 facing each other. The first main surface 41 and the second main surface 42 are facing each other in the thickness direction of the piezoelectric substrate 40. When viewed from above in the thickness direction of the piezoelectric substrate 40, the piezoelectric substrate 40 is rectangular, but it is not limited to this, for example, it can also be square.

[0066] The material of the piezoelectric substrate is not limited to lithium tantalate (LiTaO3). For example, it can also be lithium niobate (LiNbO3), zinc oxide (ZnO), aluminum nitride (AlN), or lead zirconate titanate (PZT). Furthermore, the single-crystal material and cutting angle of the piezoelectric substrate can be appropriately determined based on the required specifications of the filter (filter characteristics such as passivity, attenuation, temperature characteristics, and bandwidth).

[0067] The IDT electrode 50 is disposed on the piezoelectric substrate 40. More specifically, the IDT electrode 50 is disposed on the first main surface 41 of the piezoelectric substrate 40.

[0068] The IDT electrode 50 has a first bus bar 51, a second bus bar 52, a plurality of first electrode fingers 53, and a plurality of second electrode fingers 54. The second bus bar 52 is opposite to the first bus bar 51.

[0069] A plurality of first electrode fingers 53 are connected to the first busbar 51 and extend toward the second busbar 52. The plurality of first electrode fingers 53 are integrally formed with the first busbar 51 and separate from the second busbar 52. Viewed from the thickness direction of the piezoelectric substrate 40, a gap exists between the plurality of first electrode fingers 53 and the second busbar 52. For example, the lengths of the plurality of first electrode fingers 53 are the same. Furthermore, the widths of the plurality of first electrode fingers 53 are the same.

[0070] Multiple second electrode fingers 54 are connected to the second busbar 52 and extend towards the first busbar 51. The multiple second electrode fingers 54 are integrally formed with the second busbar 52 and are separate from the first busbar 51. Viewed from the thickness direction of the piezoelectric substrate 40, gaps exist between the multiple second electrode fingers 54 and the first busbar 51. For example, the lengths of the multiple second electrode fingers 54 are the same. Furthermore, the widths of the multiple second electrode fingers 54 are the same. Figure 4A In the example, the lengths of the plurality of second electrode fingers 54 are the same as the lengths of the plurality of first electrode fingers 53. Furthermore, in... Figure 4A In the example, the width of the plurality of second electrode fingers 54 is the same as the width of the plurality of first electrode fingers 53.

[0071] The first busbar 51 and the second busbar 52 of the IDT electrode 50 are elongated strips with a second direction D2, orthogonal to a first direction D1 along the thickness direction of the piezoelectric substrate 40, as their longitudinal direction. In other words, the first busbar 51 and the second busbar 52 of the IDT electrode 50 are elongated strips with the second direction D2, which is the direction of elastic wave propagation, as their longitudinal direction. In the IDT electrode 50, the first busbar 51 and the second busbar 52 are opposite each other in a third direction D3, orthogonal to both the first direction D1 and the second direction D2.

[0072] In the IDT electrode 50, a plurality of first electrode fingers 53 and a plurality of second electrode fingers 54 are arranged isolated from each other in the second direction D2. Here, the plurality of first electrode fingers 53 and the plurality of second electrode fingers 54 are arranged alternately, one by one, in the second direction D2, but this is not a limitation. Adjacent first electrode fingers 53 and second electrode fingers 54 are separated. A group of electrode fingers including a plurality of first electrode fingers 53 and a plurality of second electrode fingers 54 can be a structure in which the plurality of first electrode fingers 53 and the plurality of second electrode fingers 54 are arranged alternately in the second direction D2, or it can be a structure in which the plurality of first electrode fingers 53 and the plurality of second electrode fingers 54 are not alternately arranged. For example, it is also possible to have a region where each of the first electrode fingers 53 and the second electrode fingers 54 is arranged one apart, and a region where two of the first electrode fingers 53 or the second electrode fingers 54 are arranged in the second direction D2. The first busbar 51 is a conductor portion for setting the plurality of first electrode fingers 53 to the same potential (equipotential). The second busbar 52 is a conductor section used to set multiple second electrode fingers 54 to the same potential (equipotential).

[0073] The IDT electrode 50 has an intersection region 55 defined by a plurality of first electrode fingers 53 and a plurality of second electrode fingers 54. The intersection region 55 is the region between the envelope of the leading edge of the plurality of first electrode fingers 53 and the envelope of the leading edge of the plurality of second electrode fingers 54. The IDT electrode 50 excites an elastic wave in the intersection region 55.

[0074] The electrode finger spacing P1 of the IDT electrode 50 can be defined, for example, by the distance between the center lines of two adjacent first electrode fingers 53 among a plurality of first electrode fingers 53, or by the distance between the center lines of two adjacent second electrode fingers 54 among a plurality of second electrode fingers 54. The distance between the center lines of two adjacent second electrode fingers 54 is the same as the distance between the center lines of two adjacent first electrode fingers 53. Furthermore, as... Figure 4A As shown, if the width of the first electrode finger 53 in the second direction D2 is set to W1, and the interval between adjacent first electrode fingers 53 and second electrode fingers 54 in the second direction D2 is set to G1, then the duty cycle of the IDT electrode 50 can be defined by W1 / (W1+G1). Furthermore, the thickness H1 of the IDT electrode 50 can be defined, for example, by the thickness of the plurality of first electrode fingers 53 and the plurality of second electrode fingers 54.

[0075] In the IDT electrode 50, as an example, the number of pairs of first electrode fingers 53 and second electrode fingers 54 is 100. That is, as an example, the IDT electrode 50 has 100 first electrode fingers 53 and 100 second electrode fingers 54. Furthermore, in Figure 4A In 4B, the number of the first electrode finger 53 and the second electrode finger 54 has been reduced to make the attached diagram easier to observe.

[0076] The IDT electrode 50 is a standard type of IDT electrode, but it is not limited to this. For example, it can also be an IDT electrode with apodized weighting or a tilted IDT electrode. In the IDT electrode with apodized weighting, the cross width increases as it approaches the center from one end in the direction of elastic wave propagation, and decreases as it approaches the other end from the center in the direction of elastic wave propagation.

[0077] The filter 3 has multiple wiring sections 7. The multiple wiring sections 7 include a first wiring section 71 connected to the first bus bar 51 of the IDT electrode 50 and a second wiring section 72 connected to the second bus bar 52 of the IDT electrode 50.

[0078] The first wiring section 71 extends from the first busbar 51 to the side opposite to the side of the plurality of first electrode fingers 53. The second wiring section 72 extends from the second busbar 52 to the side opposite to the side of the plurality of second electrode fingers 54.

[0079] (1.3) Equivalent circuit of a specific resonator

[0080] In each of the multiple filters 3, such as Figure 5 As shown in Figure 6, the equivalent circuit of a specific resonator 4A among the multiple resonators 4 can be represented by the equivalent resistance R. m Equivalent inductor L m and equivalent capacitance C m It can be represented by a series circuit and a parallel circuit of damping capacitor C0. Figure 5 This is the equivalent circuit diagram of the mBVD ​​model corresponding to a specific resonator 4A. Figure 5 In the above, when an AC power supply is connected between the two ends of the equivalent circuit of a specific resonator 4A, the current from the AC power supply input to the specific resonator 4A is defined as Iw, and the current flowing through the equivalent resistance R is... m Equivalent inductor L m and equivalent capacitance C m The current in the series circuit is defined as Iac, and the current flowing through the damping capacitor C0 is defined as Ie. Hereinafter, the equivalent resistance R... m Equivalent inductor L m and equivalent capacitance C m The series circuit is called acoustic path 43, and the current Iac flowing through acoustic path 43 is called acoustic path current. Furthermore, the path containing damping capacitor C0 and connected in parallel with acoustic path 43 is called electrical path 44, and the current Ie flowing through electrical path 44 is called electrical path current. A specific resonator 4A includes acoustic path 43 and electrical path 44. Acoustic path 43 and electrical path 44 are connected in parallel.

[0081] It is known that the distortion caused by the nonlinearity of the elastic constant of the elastic wave resonator is proportional to the magnitude of the excitation per unit area of ​​the elastic wave resonator. The magnitude of the excitation per unit area of ​​resonator 4A is related to the magnitude of the current per unit area of ​​acoustic path 43. Therefore, the distortion caused by the nonlinearity of the elastic constant of resonator 4A is proportional to the magnitude of the current per unit area of ​​acoustic path 43. The unit area of ​​acoustic path 43 is proportional to the capacitance of damping capacitor C0. Therefore, if the current value of acoustic path current Iac divided by the capacitance of damping capacitor C0 is defined as current density Jac, then by comparing current densities Jac, the nonlinear distortion caused by the nonlinearity of the elastic constant of resonator 4A can be compared. The smaller the current density Jac, the smaller the distortion caused by the nonlinearity of the elastic constant of resonator 4A. If the unit of the current value of acoustic path current Iac is mA and the unit of the capacitance of damping capacitor C0 is pF, then the unit of current density Jac is mA / pF.

[0082] Figure 7 It shows about Figure 5 The impedance-frequency characteristic graph of the 4A resonator. Figure 7 In the Smith chart, the horizontal axis represents frequency, and the vertical axis represents impedance. The impedance Zw of resonator 4A is at its minimum at the resonant frequency fr and at its maximum at the anti-resonant frequency fa. If the frequency becomes higher than the anti-resonant frequency fa, the impedance Zw of resonator 4A shifts clockwise on the Smith chart, becoming a capacitive impedance. Figure 7 In the diagram, the frequency characteristics of the impedance Zw of resonator 4A are shown by solid lines, the frequency characteristics of the impedance Ze of electrical path 44 are shown by dashed lines, and the frequency characteristics of the impedance Zac of acoustic path 43 are shown by dashed lines.

[0083] like Figure 7 As shown, at the resonant frequency fr, the impedance Zw of resonator 4A and the impedance Zac of acoustic path 43 become almost zero. If the equivalent inductor L included in acoustic path 43 is... m The inductance is set to L1, and the equivalent capacitance C is set to L2. m If the capacitance is set as C1, then the resonant frequency fr can be expressed as the following equation (1).

[0084] [Mathematical Expression 1]

[0085]

[0086] like Figure 7As shown, at the anti-resonant frequency fa, the impedance Zw of resonator 4A becomes a maximum value. At the anti-resonant frequency fa, which is higher than the resonant frequency fr, the impedance Zac becomes inductive. Therefore, at the anti-resonant frequency fa, the acoustic path 43 can be regarded as an inductive element, and the resonator 4A can be regarded as an LC parallel resonant circuit of an inductive element and a damping capacitor C0. Here, if the inductance of the inductive element is Lac, and the capacitance of the damping capacitor C0 of the electrical path 44 is C0e, then the anti-resonant frequency fa can be expressed as the following equation (2).

[0087] [Mathematical Expression 2]

[0088]

[0089] Figure 8 This is a graph showing the current-frequency characteristics of the resonator 4A. Figure 8 In the diagram, the horizontal axis represents frequency, and the vertical axis represents current. Figure 8 In the diagram, the frequency characteristics of the current Iw flowing through the resonator 4A are shown by a solid line, the frequency characteristics of the current Ie flowing through the electrical path 44 are shown by a single-dot dashed line, and the frequency characteristics of the current Iac flowing through the acoustic path 43 are shown by a dashed line.

[0090] like Figure 8 As shown, at the resonant frequency fr, almost no current Ie flows through the electrical path 44. At the resonant frequency fr, the current Iac flowing through the acoustic path 43 is approximately the same as the current Iw flowing through the resonator 4A.

[0091] like Figure 8 As shown, at the anti-resonant frequency fa, the current Iw through resonator 4A becomes extremely small. Furthermore, at the anti-resonant frequency fa, the current Ie flowing through electrical path 44 and the current Iac flowing through acoustic path 43 become approximately the same magnitude. This is because, inside resonator 4A, the current circulates in a closed circuit containing acoustic path 43 and electrical path 44. In this case, the current Ie in electrical path 44 and the current Iac in acoustic path 43 are out of phase. At the anti-resonant frequency fa, almost no current Iw flows through resonator 4A, but a relatively large current flows inside resonator 4A.

[0092] Figure 9 It is shown Figure 5 The phase-frequency response of resonator 4A is plotted. Figure 9 In the diagram, the horizontal axis represents frequency, and the vertical axis represents phase. Figure 9 In the diagram, the phase θw of the current Iw flowing through resonator 4A is shown by a solid line, the phase θe of the current Ie flowing through electrical path 44 is shown by a dashed line, and the phase θac of the current Iac flowing through acoustic path 43 is shown by a dashed line.

[0093] according to Figure 9 It can be seen that the phase of the current Iac flowing through acoustic path 43 at the anti-resonant frequency fa is the phase of the current Ie flowing through electrical path 44 reversed. If we define the current value of Iac flowing through acoustic path 43 at the anti-resonant frequency fa as Iac... fa The current value of Ie flowing through electrical path 44 at the anti-resonant frequency fa is set as Ie. fa Let the Q value of resonator 4A at the anti-resonant frequency fa be Qa, and let the current Iw through resonator 4A at the anti-resonant frequency fa be the reference current value Iw. fa If we set the imaginary unit to j, then Iac fa 、Ie fa They can be expressed as equations (3) and (4) below.

[0094] [Mathematical Expression 3]

[0095] Iac fa =-j·Qa·Iw fa Equation (3)

[0096] [Mathematical Expression 4]

[0097] Ie fa =j·Qa·Iw fa Equation (4)

[0098] The current value Iac flowing through acoustic path 43 at the anti-resonant frequency fa. fa Become the reference current value Iw fa The value is Qa times greater. Therefore, in order to reduce the nonlinear distortion caused by the nonlinearity of the elastic constant of the resonator 4A, the reference current value Iw needs to be reduced. fa .

[0099] also, Figure 10 It is shown Figure 5 The voltage-frequency characteristic graph of the 4A resonator. Figure 10 In the diagram, the horizontal axis represents frequency, and the vertical axis represents voltage. Figure 10 In the diagram, the frequency response of the voltage Vw of resonator 4A is shown by a solid line. The voltages of electrical path 44 and acoustic path 43 are the same as the voltage of resonator 4A.

[0100] In resonator 4A, the larger the capacitance of damping capacitor C0, the smaller the impedance Zw of resonator 4A. Furthermore, in resonator 4A, the larger the capacitance of damping capacitor C0, the larger the current Iac flowing through acoustic path 43. Also, in resonator 4A, the larger the capacitance of damping capacitor C0, the smaller the current density of current Iac flowing through acoustic path 43.

[0101] The current Iac flowing through the acoustic path 43 and the capacitance of the damping capacitor C0 in the equivalent circuit of resonator 4A can be determined, for example, by the following method.

[0102] Replace the resonator 4A with a circuit simulator such as ADS (Advanced Design System). Figure 5 The equivalent circuit model (mBVD model) shown is used to fit the waveform of the measured impedance and the filter characteristics. Through characteristic fitting, the equivalent inductor L is determined. m Equivalent capacitance C m Equivalent resistance R m And the circuit constants of the damping capacitor C0. Therefore, the capacitance of the damping capacitor C0 is determined. After characteristic fitting, the current flowing through the acoustic path 43 of the resonator 4A is calculated using the ammeter of the circuit simulator, thus confirming the current value of the acoustic path current Iac. By dividing the current value of the acoustic path current Iac by the capacitance of the damping capacitor C0, the current density Jac of the acoustic path current Iac can be derived.

[0103] The capacitance of the damping capacitor C0 can also be determined using the following method.

[0104] When comparing the capacitances of the damping capacitors C0 of multiple resonators 4A, the capacitances of the damping capacitors C0 can be compared by contacting the probe with the first busbar 51 and the second busbar 52 of the resonator 4A respectively, or by contacting the probe with the first wiring portion 71 connected to the first busbar 51 and the second wiring portion 72 connected to the second busbar 52 of the resonator 4A respectively, measuring the impedance of the resonator 4A, and comparing the frequency characteristics in the frequency region separated from the resonant frequency fr to the anti-resonant frequency fa. Furthermore, the capacitance of the damping capacitor C0 of the resonator 4A can also be determined by applying a DC voltage to the resonator 4A.

[0105] (1.4) The third-order IMD of the multiplexer (IMD3)

[0106] In multiplexer 1, there is a tendency that the closer the resonator 4 is to the common terminal 2, the greater the distortion caused by the nonlinearity of the elastic constant.

[0107] In multiplexer 1, if dual uplink carrier aggregation utilizing the first transmit filter 31 and the second transmit filter 33 is performed, an IMD (Incoming Disturbance) is generated. If the frequency included in the passband of the first transmit filter 31 is set to f1, and the frequency included in the passband of the second transmit filter 33 is set to f2, then an IMD3 of f3 = 2 × f1 - f2 is generated near the first and second transmit bands. Therefore, when the passbands of the first receive filter 32, the first transmit filter 31, and the second transmit filter 33 are relatively close, IMD3 often becomes a problem. When the passband of the first transmit filter 31 is 1850MHz-1915MHz and the passband of the second transmit filter 33 is 1710MHz-1780MHz, the frequency band generating IMD3 is 1930MHz-1995MHz.

[0108] In multiplexer 1, the level and phase of IMD3 of each resonator 4A can be expressed by the current density and the capacitance of the damping capacitor C0 using the following equations (5) and (6).

[0109] [Mathematical Expression 5]

[0110] IMD3 level = |J B25TX | 2 ×|J B66TX |×C0 TX (5)

[0111] [Mathematical Expression 6]

[0112] Phase of IMD3 = 2θ B25TX ±θ B66TX 2θ B66TX ±θ B25TX Equation (6)

[0113] In equation (5), J B25TX The complex number representing the acoustic path current density in the transmit band of Band 25, |J B25TX | indicates the magnitude of the acoustic path current in the transmit band of Band 25. Additionally, J B66TX The complex number representing the acoustic path current density in the transmit band of Band 66, |J B66TX | indicates the magnitude of the acoustic path current in the transmit band of Band66. Additionally, C0 TX This represents the capacitance of the damping capacitor C0. The unit of IMD3 voltage level is ampere-amperes (A). 3 / pF 2 In equation (6), θ B25TX This indicates the phase of the acoustic path current in the transmit band of Band 25. Furthermore, θ B66TX This indicates the phase of the acoustic path current in the transmit band of Band66.

[0114] exist Figure 11A The frequency characteristics of the IMD3 level generated in the third passband of the first receiving filter 32 in a specific resonator 4A (parallel arm resonator P14) of the first transmitting filter 31 with a transmitting band of Band 25 as the first passband are shown, and the frequency characteristics of the IMD3 level generated in the third passband of the first receiving filter 32 in a specific resonator 4A (series arm resonator S34) of the second transmitting filter 33 with a transmitting band of Band 66 as the second passband are shown. Figure 11A The results of the evaluation were based on the following scenario: multiplexer 1 received a signal with a power input of +26dBm within the transmit band of Band 25 (1850MHz-1860MHz) and a signal with a power input of +10dBm within the transmit band of Band 66 (1770MHz-1780MHz) from common terminal 2. The evaluation focused on the IMD generated in the receive band of Band 25 between 1930MHz and 1940MHz. In multiplexer 1, when high power was input, the first transmit filter 31 and the second transmit filter 33 became the primary sources of IMD. In this case, the parallel arm resonator P14, which is a specific resonator 4A corresponding to the transmit band of Band 25, and the series arm resonator S34, which is a specific resonator 4A corresponding to the transmit band of Band 66, became the primary sources of IMD. Figure 11B It was conducted with Figure 11A The frequency response diagram of the phase of IMD3 under the same evaluation conditions. Figure 11B The diagram shows the frequency characteristics of the phase of IMD3 generated in the third passband of the first receiving filter 32 in a specific resonator 4A (parallel arm resonator P14) of the first transmitting filter 31 with a transmitting band of Band 25 as the first passband, and the frequency characteristics of the phase of IMD3 generated in the third passband of the first receiving filter 32 in a specific resonator 4A (series arm resonator S34) of the second transmitting filter 33 with a transmitting band of Band 66 as the second passband. According to... Figure 11B It can be seen that the phase of IMD3 is reversed in the first transmitting filter 31 and the second transmitting filter 33. That is, by setting the specific resonator 4A of the first transmitting filter 31 as the parallel arm resonator P14, the phase of IMD3 of the first transmitting filter 31 can be shifted by nearly 180° from the phase of IMD3 of the second transmitting filter 33. Therefore, the cancellation effect of IMD3 of the first transmitting filter 31 and the second transmitting filter 33 is evident, which can reduce the overall level of IMD3. Furthermore, according to... Figure 11A It can be seen that the level of IMD3 of the first transmitting filter 31 (refer to...) Figure 11AThe level of B25Tx is greater than that of IMD3 of the second transmit filter 33 (refer to...). Figure 11A (B66Tx). Furthermore, although not illustrated, the IMD3 level of the first transmit filter 31 and the IMD3 level of the second transmit filter 33 are greater than the IMD3 levels of the other filters 3 (first receive filter 32, second receive filter 34).

[0115] Regarding multiplexer 1, I1 is defined as follows: TX1 I2 TX1 C0 TX1 I1 TX2 I2 TX2 C0 TX2 I1 RX1 I2 RX1 C0 RX1 I1 RX2 I2 RX2 and C0 RX2 .

[0116] I1 TX1 I2 is the density of the acoustic path current on the common terminal 2 side of the first transmitting filter 31 at the frequency within the first passband. TX1 It is the density of the acoustic path current on the common terminal 2 side of the first transmitting filter 31 at the frequency within the second passband. C0 TX1 It is the capacitance of the damping capacitor C0 of the specific resonator 4A in the first transmitting filter 31. 11 TX2 I2 is the density of the acoustic path current on the common terminal 2 side of the second transmitting filter 33 at the frequency within the first passband. TX2 It is the density of the acoustic path current on the common terminal 2 side of the second transmitting filter 33 at the frequency within the second passband. C0 TX2 It is the capacitance of the damping capacitor C0 of the specific resonator 4A in the second transmitting filter 33. I1 RX1 I2 is the density of the acoustic path current on the common terminal 2 side of the first receiving filter 32 at the frequency within the first passband. RX1 It is the density of the acoustic path current on the common terminal 2 side of the first receiving filter 32 at the frequency within the second passband. C0 RX1 It is the capacitance of the damping capacitor C0 of the specific resonator 4A in the first receiving filter 32. I1 RX2 I2 is the density of the acoustic path current on the common terminal 2 side of the second receiving filter 34 at frequencies within the first passband. RX2 It is the density of the acoustic path current on the common terminal 2 side of the second receiving filter 34 at the frequency within the second passband. C0 RX2 It is the capacitance of the damping capacitor C0 of the specific resonator 4A in the second receiving filter 34.

[0117] In multiplexer 1, as described above, the IMD3 levels of the first transmitting filter 31 and the second transmitting filter 33 are greater than the IMD3 levels of the other filters 3, that is, greater than the IMD3 levels of the first receiving filter 32 and the second receiving filter 34. Therefore, multiplexer 1 satisfies the third and fourth conditions.

[0118] The third condition is as follows:

[0119] (I1 Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 >(I1) Rx1 ) 2 ·(I2 Rx1 )·C0 Rx1 .

[0120] The fourth condition is as follows:

[0121] (I1 Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 >(I1) Rx1 ) 2 ·(I2 Rx1 )·C0 Rx1 .

[0122] Regarding the IMD3 of filter 3, in most cases, the resonator 4 closest to the common terminal 2 becomes the dominant factor. In the case of the multiplexer 1 according to Embodiment 1, the level of the IMD3 of a specific resonator 4A of the first transmitting filter 31 and the level of the IMD3 of a specific resonator 4A of the second transmitting filter 33 are greater than the levels of the IMD3 of specific resonators 4A of the other filters 3 (the first receiving filter 32 and the second receiving filter 34). Therefore, in the case of the multiplexer 1 according to Embodiment 1, in most cases, the IMD3 of a specific resonator 4A of the first transmitting filter 31 and the IMD3 of a specific resonator 4A of the second transmitting filter 33 become the dominant factor. Therefore, in specific resonators 4A of the first transmitting filter 31 and specific resonators 4A of the second transmitting filter 33, if the phase of IMD3 is 180°±90° (±90° means -90° to +90°. Therefore, the phase of IMD3 is a value above 90° and below 270°), the IMD3 as a whole of the multiplexer 1 can be improved. If the IMD3 level is approximately the same, the IMD3 as a whole of the multiplexer 1 can be further improved.

[0123] In multiplexer 1, if the IMD generation levels from the two IMD generation sources are of the same degree and approximately opposite in phase (180° offset), the IMDs cancel each other out and become almost unobservable. The IMD3 levels of specific resonators 4A (parallel arm resonators P14) of the first transmit filter 31 and the specific resonators 4A (series arm resonators S34) of the second transmit filter 33 exhibit similar tendencies with respect to frequency changes; therefore, if the IMD3 level can be adjusted and its phase made approximately opposite, IMD3 can be reduced. In multiplexer 1 according to embodiment 1, for example, the IMD3 level is changed by altering the capacitance of the damping capacitor C0 in the specific resonators 4A of the first transmit filter 31 and the second transmit filter 33. If the capacitance of the damping capacitor C0 is increased, the IMD3 level decreases; if the capacitance of the damping capacitor C0 is decreased, the IMD3 level increases. Regarding the level of IMD3, assuming that the damping capacitance C0 of the specific resonators 4A in the first transmit filter 31 and the second transmit filter 33 is the same, then the specific resonator 4A of the first transmit filter 31, which receives a large power input, becomes larger than the specific resonator 4A of the second transmit filter 33. Therefore, for example, by making the damping capacitance C0 of the specific resonator 4A (parallel arm resonator P14) in the first transmit filter 31 larger than the damping capacitance C0 of the specific resonator 4A (series arm resonator S34) in the second transmit filter 33, it is possible to make the level of IMD3 consistent (reduce the difference in IMD3 level) in the specific resonators 4A of the first transmit filter 31 and the specific resonators 4A of the second transmit filter 33. An example of the capacitance of the damping capacitance C0 of the specific resonator 4A of each filter 3 is shown in Table 1.

[0124] [Table 1]

[0125]

[0126] In Table 1, B66Tx represents the second transmitting filter 33, B25Tx represents the first transmitting filter 31, B25Rx represents the first receiving filter 32, and B66Rx represents the second receiving filter 34. Furthermore, in Table 1, S34 represents the series arm resonator S34, P14 represents the parallel arm resonator P14, S24 represents the series arm resonator S24, and S44 represents the series arm resonator S44. Additionally, in Table 1, the area represents the product of the cross width of the first electrode finger 53 and the second electrode finger 54 (the width W55 of the cross region 55 in the third direction D3) and the logarithm of the cross region 55. That is, the size relationship of the areas in Table 1 is the same as the size relationship of the cross region 55.

[0127] According to Table 1, the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 is 2.352pF, while the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 is 1.932pF.

[0128] Figure 12 This is a frequency response diagram of the IMD3 level when the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 is set to 1.5 times the capacitance of the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33. According to... Figure 12 It can be seen that in the specific resonator 4A (series arm resonator S34) of the second transmitting filter 33 and the specific resonator 4A (parallel arm resonator P14) of the first transmitting filter 31, the magnitude of IMD3 can be made approximately the same. Therefore, in the multiplexer 1, the IMD3 of the two filters 3 with larger IMD3 levels are canceled out, and the total IMD3 level becomes smaller.

[0129] The phase of the IMD can be adjusted by multiple phase-shifting circuits 8, which correspond one-to-one with the multiple filters 3 and are connected between the multiple filters 3 and the common terminal 2. The IMD3 generated in the specific resonator 4A of each filter 3 reaches the first receiving filter 32, which includes the frequency band in the third passband that generates the IMD3, via the phase-shifting circuit 8. Therefore, by providing the phase-shifting circuit 8 between each filter 3 and the common terminal 2, the phase of the IMD3 can be changed. The phase-shifting circuit 8 can also be an inductor or a capacitor, or a circuit combining an inductor and a capacitor, or wiring (transmission line). Each phase-shifting circuit 8 is provided for adjusting the phase of the IMD3 from the corresponding filter 3 to the common terminal 2, but it is not necessarily required. However, in the multiplexer 1, it is preferable to provide a first phase-shifting circuit 81 between the first transmitting filter 31 and the common terminal 2. This is because the first transmitting filter 31 is the filter 3 with the strongest input power among the multiple filters 3, and has a large influence on the IMD3, so it is also easy to perform IMD3 adjustment based on phase adjustment.

[0130] (1.5) Construction of a specific resonator

[0131] In the multiplexer 1 according to Embodiment 1, as described above, the capacitance of the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 is less than the capacitance of the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31.

[0132] Figure 13A This is a top view of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31. Figure 13B This is a top view of a specific resonator 4A (series arm resonator S44) in the second transmitting filter 33. The specific resonator 4A ( Figure 13B In ), with the specific resonator 4A in the first transmitting filter 31 ( Figure 13A Compared to the first electrode finger 53, the intersection width of the first electrode finger 53 and the second electrode finger 54 is smaller, and the area of ​​the intersection region 55 is smaller. Therefore, it becomes easier to make the damping capacitance C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 smaller than the damping capacitance C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31.

[0133] (2) Summary

[0134] The multiplexer 1 according to embodiment 1 includes a common terminal 2 and multiple filters 3. The multiple filters 3 are connected to the common terminal 2. Each of the multiple filters 3 has multiple resonators 4. The multiple filters 3 include a first transmitting filter 31 and a second transmitting filter 33. The first transmitting filter 31 has a first passband. The second transmitting filter 33 has a second passband different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. In the multiplexer 1, the equivalent circuit of a specific resonator 4A among the multiple resonators 4 is represented by an equivalent resistance R in each of the multiple filters 3. m Equivalent inductor L m and equivalent capacitance C m When representing the series circuit and the parallel circuit of the damping capacitor C0, if the current flowing through the damping capacitor C0 is set as the acoustic path current Iac, then the phase of the acoustic path current Iac on the common terminal 2 side of the first transmitting filter 31 at the frequency within the first passband is set as θ1. Tx1 The phase of the acoustic path current Iac on the common terminal 2 side of the first transmitting filter 31 at the frequency within the second passband is set to θ2. Tx1 The phase of the acoustic path current Iac on the common terminal 2 side of the second transmitting filter 33 at the frequency within the first passband is set to θ1. Tx2 The phase of the acoustic path current Iac on the common terminal 2 side of the second transmitting filter 33 at the frequency within the second passband is set to θ2. Tx2 In this case, multiplexer 1 satisfies either condition 1 or condition 2. Condition 1 is as follows: |(2·θ1) Tx1 -θ2 Tx1 )-(2·θ1 Tx2 -θ2 Tx2The second condition is as follows: |(2·θ²) = 180° ± 90°. Tx1 -θ1 Tx1 )-(2·θ2 Tx2 -θ1 Tx2 )|=180°±90°.

[0135] In the multiplexer 1 according to Embodiment 1, the generation of IMD can be suppressed. Therefore, in the multiplexer 1 according to Embodiment 1, the decrease in the receiving sensitivity of the first receiving filter 32 can be suppressed. In the multiplexer 1 according to Embodiment 1, for example, when the levels of IMD3 in the first transmitting filter 31 and the second transmitting filter 33 are the same, if the phase difference between the IMD3 of the first transmitting filter 31 and the IMD3 of the second transmitting filter 33 is 180°, then the IMD3 of the first transmitting filter 31 and the IMD3 of the second transmitting filter 33 are canceled out. Furthermore, it is not limited to the case where the phase difference between the IMD3 of the first transmitting filter 31 and the IMD3 of the second transmitting filter 33 is 180°; as long as it is in the range of 90° or more and 270° or less, the overall level of IMD3 can be reduced.

[0136] (3) Variations

[0137] (3.1) Variation Example 1

[0138] The circuit structure of the multiplexer 1 involved in Variation 1 of Embodiment 1 is the same as that of the multiplexer 1 involved in Embodiment 1 (see reference). Figure 1 The circuit structure is the same as that in 6), therefore the diagram and explanation are omitted. See below for reference. Figure 14A And 14B provides an explanation of the multiplexer 1 involved in Modification 1.

[0139] Figure 14A This is a top view of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31. Figure 14B This is a top view of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33. The specific resonator 4A ( Figure 14B In ), with the specific resonator 4A in the first transmitting filter 31 ( Figure 14A Compared to the first electrode finger 53 and the second electrode finger 54, the number of logarithms is smaller, and the area of ​​the intersection region 55 is smaller. Therefore, compared to the capacitance of the damping capacitance C0 of the specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31, the capacitance of the damping capacitance C0 of the specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 can be reduced.

[0140] Furthermore, even if the capacitance of the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 and the capacitance of the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 are set to be the same, the power density of the parallel arm resonator P14 can be reduced and the level of IMD3 can be reduced by making the area of ​​the parallel arm resonator P14 larger than that of the series arm resonator S34.

[0141] (3.2) Variation Example 2

[0142] The circuit structure of the multiplexer 1 involved in Variation 2 of Embodiment 1 is the same as that of the multiplexer 1 involved in Embodiment 1 (see reference). Figure 1 The circuit structure of circuit 6) is roughly the same, therefore the diagram and explanation are omitted. See below for reference. Figure 15A , 15B 16A and 16B will be used to describe the multiplexer 1 involved in Modification Example 2.

[0143] Figure 15A The circuit diagram shows that the specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 is composed of three segmented resonators 401. Figure 15B This is a top view of a specific resonator 4A in the first transmitting filter 31. Here, the three segmented resonators 401 are resonators that are segmented from the specific resonator 4A (parallel arm resonator P14) and are connected in series with each other without passing through other resonators 4 and without passing through a connection node containing the path of other resonators 4. Figure 16A The circuit diagram shows that the second transmitting filter 33 is composed of two segmented resonators 401 forming a specific resonator 4A (series arm resonator S34). Figure 16B This is a top view of a specific resonator 4A in the second transmitting filter 33. Here, the two split resonators 401 are resonators that are split from the specific resonator 4A (series arm resonator S34) and are connected in series with each other without passing through other resonators 4 and without passing through a connection node containing the path of other resonators 4. Figure 15B The area of ​​the specific resonator 4A is the sum of the areas of the three cross regions 55. Figure 16B The area of ​​the specific resonator 4A is the sum of the areas of the two cross regions 55. Figure 15B as well as Figure 16B In the middle, the area of ​​the intersection region 55 of each segmented resonator 401 is the same.

[0144] In the multiplexer 1 involved in the variation 2 of embodiment 1, even if the capacitance of the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 and the capacitance of the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 are set to be the same, the power density of the parallel arm resonator P14 can be reduced by making the area of ​​the parallel arm resonator P14 larger than the area of ​​the series arm resonator S44, thereby reducing the level of IMD3. Preferably, the areas of the cross regions 55 of the multiple segmented resonators 401 in the specific resonator 4 are the same, but this is not a limitation; the areas of the cross regions 55 may also be approximately the same.

[0145] In the multiplexer 1 involved in the variation 2 of embodiment 1, as long as the number of divisions of a specific resonator 4A in the first transmitting filter 31 is greater than the number of divisions of a specific resonator 4A in the second transmitting filter 33, there is no particular limitation on the number of divisions of the specific resonator 4A in the first transmitting filter 31 and the number of divisions of the specific resonator 4A in the second transmitting filter 33.

[0146] (3.3) Variation Example 3

[0147] The circuit structure of the multiplexer 1 involved in Variation 3 of Embodiment 1 is the same as that of the multiplexer 1 involved in Embodiment 1 (see reference). Figure 1 The circuit structure is the same as that in 6), therefore the diagram and explanation are omitted. See below for reference. Figure 17A And 17B provides an explanation of the multiplexer 1 involved in variation 3.

[0148] Figure 17A This is a top view of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31. Figure 17B This is a top view of a specific resonator 4A (series arm resonator S34) in the first receiving filter 32. Regarding the specific resonator 4A in the first receiving filter 32 ( Figure 17B The width of the first electrode finger 53 in the second direction D2 is set to W12, and the interval between adjacent first electrode fingers 53 and second electrode fingers 54 in the second direction D2 is set to G12. The duty cycle at this time is W12 / (W12+G12). Regarding the specific resonator 4A in the first transmitting filter 31... Figure 17AThe width of the first electrode finger 53 in the second direction D2 is set to W11, and the interval between adjacent first electrode fingers 53 and second electrode fingers 54 in the second direction D2 is set to G11. At this time, the duty cycle = W11 / (W11+G11) and the duty cycle = W12 / (W12+G12) is less than the duty cycle = W11 / (W11+G11). Therefore, compared to the capacitance of the damping capacitance C0 of the specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31, the capacitance of the damping capacitance C0 of the specific resonator 4A (series arm resonator S34) in the first receiving filter 32 can be reduced.

[0149] Although in the multiplexer 1 according to Variation 3 of Embodiment 1, the duty cycle of a specific resonator 4A in the second transmit filter 33 is set to 0.3 and the duty cycle of a specific resonator 4A in the first transmit filter 31 is set to 0.5, these values ​​are merely examples and are not limited to these values. Although in the multiplexer 1 according to Variation 3 of Embodiment 1, the duty cycle of a specific resonator 4A in the second transmit filter 33 is less than the duty cycle of a specific resonator 4A in the first transmit filter 31, this is not a limitation. The duty cycle of a specific resonator 4A in the second transmit filter 33 can also be greater than the duty cycle of a specific resonator 4A in the first transmit filter 31. In this case, by increasing the duty cycle of a specific resonator 4A in the second transmit filter 33, the level of IMD3 in the second transmit filter 33 can be increased. Therefore, the difference between the level of IMD3 in the second transmit filter 33 and the level of IMD3 in the first transmit filter 31 can be easily reduced, and the mutual cancellation effect of IMD3 can be easily achieved.

[0150] (Implementation Method 2)

[0151] The circuit structure of the multiplexer 1 involved in Embodiment 2 is the same as that of the multiplexer 1 involved in Embodiment 1 (see reference). Figure 1 The circuit structure is the same as that in 6), therefore the diagram and explanation are omitted. See below for reference. Figure 18A And 18B describes the multiplexer 1 involved in Embodiment 2.

[0152] In the multiplexer 1 according to embodiment 2, the thickness H1 of the IDT electrode 50 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 (refer to...) Figure 18A The thickness H2 of the IDT electrode 50 of the specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 is less than that of the first transmitting filter 33. Figure 18BTherefore, in the multiplexer 1 according to Embodiment 2, even if the capacitance of the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 and the capacitance of the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmitting filter 33 are set to be the same, the level of IMD3 can be reduced.

[0153] (Implementation Method 3)

[0154] The circuit structure of the multiplexer 1 involved in Embodiment 3 is the same as that of the multiplexer 1 involved in Embodiment 1 (refer to...). Figure 1 The circuit structure is the same as that in 6), therefore the diagram and explanation are omitted. See below for reference. Figures 19A-19C The multiplexer 1 involved in Embodiment 3 will be described.

[0155] In the multiplexer 1 according to embodiment 3, the IDT electrode 50 (refer to) of a specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 is... Figure 19A ) is set as a polycrystalline metal electrode, and the IDT electrode 50 of the specific resonator 4A (series arm resonator S44) in the second transmit filter 33 (refer to) Figure 19C ) is set as the epitaxial layer of the metal.

[0156] For example, such as Figure 19A As shown, the IDT electrode 50 of the parallel arm resonator P14 includes a close-packed layer 501 composed of a first polycrystalline layer on the first main surface 41 of the piezoelectric substrate 40, and a main electrode layer 502 composed of a second polycrystalline layer on the close-packed layer 501. The first polycrystalline layer is, for example, a polycrystalline Ti layer. The second polycrystalline layer is, for example, a polycrystalline Al layer. For example, as... Figure 19C As shown, the IDT electrode 50 of the series arm resonator S34 includes a close-packed layer 511 composed of a first epitaxial layer on the first main surface 41 of the piezoelectric substrate 40, and a main electrode layer 512 composed of a second epitaxial layer on the close-packed layer 511. The first epitaxial layer is, for example, a Ti epitaxial layer. The second epitaxial layer is, for example, an Al epitaxial layer. The piezoelectric substrate 40 is a piezoelectric substrate polarized along the Z-axis. Figure 19B As shown, the first main surface 41 of the piezoelectric substrate 40 before the growth of the Ti epitaxial layer and the Al epitaxial layer has a stepped structure including a Z-plane 411 orthogonal to the Z-axis direction. Figure 19BIn the diagram, the X-axis, Y-axis, and Z-axis are shown on the right side of the piezoelectric substrate 40. The close-packed layer 511, composed of a Ti epitaxial layer, is an epitaxial growth layer that grows epitaxially in the Z-axis direction on the Z-plane 411 of the piezoelectric substrate 40, such that the Ti(001) plane, which serves as the crystal growth surface, is parallel to the Z-plane 411 of the piezoelectric substrate 40. Furthermore, the main electrode layer 512, composed of an Al epitaxial layer, is an epitaxial growth layer that grows epitaxially in the Z-axis direction on the surface of the close-packed layer 511, such that the Al(111) plane, which serves as the crystal growth surface, is parallel to both the Z-plane 411 and the Ti(001) plane of the piezoelectric substrate 40. Therefore, in the IDT electrode 50 of the series arm resonator S34, a main electrode layer 512 composed of an Al epitaxial layer with its crystal orientation oriented in the Z-axis direction of the piezoelectric substrate 40 is formed on the piezoelectric substrate 40. Therefore, the IDT electrode 50 of the series arm resonator S34 is an electrode formed on the piezoelectric substrate 40 with the Al (111) plane parallel to the crystal plane of the piezoelectric substrate 40. In other words, in the IDT electrode 50 of the series arm resonator S34, the

[111] direction of the main electrode layer 512, which is orthogonal to the Al (111) plane, becomes parallel to the Z-axis (c-axis) of the piezoelectric substrate 40. On the other hand, the main electrode layer 502 composed of a polycrystalline Al layer is, for example, a polycrystalline Al layer that does not meet the conditions for constituting an Al epitaxial layer of the main electrode layer 512. Here, in the main electrode layer 502 composed of a polycrystalline Al layer, for example, any one of the c-axis, a-axis, or b-axis becomes randomly oriented.

[0157] In the multiplexer 1 according to embodiment 3, the IDT electrode 50 of the parallel arm resonator P14 (refer to...) is used to... Figure 19A ) is set as a polycrystalline metal electrode, and the IDT electrode 50 of the series arm resonator S34 (refer to Figure 19C By setting the metal epitaxial layer, even if the capacitance of the damping capacitor C0 of a specific resonator 4A (parallel arm resonator P14) in the first transmit filter 31 and the capacitance of the damping capacitor C0 of a specific resonator 4A (series arm resonator S34) in the second transmit filter 33 are set to be the same, the difference between the IMD3 level in the first transmit filter 31 and the IMD3 level in the second transmit filter 33 can be reduced. Therefore, in the multiplexer 1 according to Embodiment 3, the IMD3 level can be reduced.

[0158] (Implementation Method 4)

[0159] The circuit structure of the multiplexer 1 involved in Embodiment 4 is the same as that of the multiplexer 1 involved in Embodiment 1 (see reference). Figure 1 The circuit structure is the same as that in 6), therefore the diagram and explanation are omitted. See below for reference. Figure 20A And 20B describes the multiplexer 1 involved in Embodiment 4.

[0160] In the multiplexer 1 according to embodiment 4, the IDT electrode 50 of the specific resonator 4A (parallel arm resonator P14) in the first transmitting filter 31 (refer to...) Figure 20A The material contains one or more of Pt, Mo, Au, Ag, Cu, and W. The content of one or more of Pt, Mo, Au, Ag, Cu, and W in the IDT electrode 50 of a specific resonator (parallel arm resonator P14) of the first transmitting filter 31 is higher than the content of the aforementioned one or more materials in the IDT electrode 50 of a specific resonator 4A (series arm resonator S34) of the second transmitting filter 33. Pt, Mo, Au, Ag, Cu, and W are materials with a Young's modulus greater than Al, and in the multiplexer 1 according to Embodiment 4, the distortion generated by the IDT electrode 50 can be reduced.

[0161] For example, the IDT electrode 50 of a specific resonator 4A (parallel arm resonator P14) in the first transmit filter 31 includes, for example, a Ti layer on the first main surface 41 of the piezoelectric substrate 40 and an AlCu layer on the Ti layer. Similarly, the IDT electrode 50 of a specific resonator 4A (series arm resonator S34) in the second transmit filter 33 includes a Ti layer on the first main surface 41 of the piezoelectric substrate 40 and an Al layer on the Ti layer. Furthermore, if an AlCu layer is used instead of an Al layer in the IDT electrode 50 of the second transmit filter 33, it is only necessary to ensure that the Cu content of the AlCu layer in the IDT electrode 50 of the first transmit filter 31 is higher than the Cu content of the AlCu layer in the IDT electrode 50 of the second transmit filter 33. Additionally, each IDT electrode 50 may also have, for example, a Cr layer instead of a Ti layer.

[0162] In the multiplexer 1 according to Embodiment 4, as described above, the content of one or more materials among Pt, Mo, Au, Ag, Cu, and W in the IDT electrode 50 of a specific resonator (parallel arm resonator P14) of the first transmitting filter 31 is higher than the content of the aforementioned one or more materials in the IDT electrode 50 of a specific resonator 4A (series arm resonator S34) of the second transmitting filter 33. Therefore, in the multiplexer 1 according to Embodiment 4, the generation of IMD can be further suppressed.

[0163] (Implementation Method 5)

[0164] The following is for reference Figure 21 The multiplexer 1a according to Embodiment 5 will be described. Regarding the multiplexer 1a according to Embodiment 5, the same reference numerals are used for the same constituent elements as those of the multiplexer 1 according to Embodiment 1, and the description is omitted.

[0165] In Embodiment 5, the multiplexer 1a replaces the first receiving filter 32 and the second receiving filter 34 in Embodiment 1 and includes a first receiving filter 32a and a second receiving filter 34a.

[0166] The first receiving filter 32a differs from the first receiving filter 32 in that it has a longitudinally coupled resonator 404 between the series arm resonator S23 and the parallel arm resonator P21. Furthermore, the second receiving filter 34a differs from the second receiving filter 34 in that it has a parallel circuit of longitudinally coupled resonators 402 and 403 between the series arm resonator S44 (which is a specific resonator 4A) and the parallel arm resonator P41.

[0167] The multiplexer 1a in Embodiment 5 is similar to the multiplexer 1 in Embodiment 1, in that the phase of the acoustic path current Iac on the common terminal 2 side of the first transmitting filter 31 at the frequency within the first passband is set to θ1. Tx1 The phase of the acoustic path current Iac on the common terminal 2 side of the first transmitting filter 31 at the frequency within the second passband is set to θ2. Tx1 The phase of the acoustic path current Iac on the common terminal 2 side of the second transmitting filter 33 at the frequency within the first passband is set to θ1. Tx2 The phase of the acoustic path current Iac on the common terminal 2 side of the second transmitting filter 33 at the frequency within the second passband is set to θ2. Tx2 In this case, either condition 1 or condition 2 is satisfied. Condition 1 is as follows: |(2·θ1) Tx1 -θ2 Tx1 )-(2·θ1 Tx2 -θ2 Tx2 The second condition is as follows: |(2·θ²) = 180° ± 90°. Tx1 -θ1 Tx1 )-(2·θ2 Tx2 -θ1 Tx2 )|=180°±90°.

[0168] In the multiplexer 1a according to Embodiment 5, similarly to the multiplexer 1 according to Embodiment 1, the generation of IMD can be suppressed.

[0169] The above-described embodiments 1 and their variations 1-3, and embodiments 2-5, are merely one of many embodiments of the present invention. As long as the purpose of the present invention can be achieved, the above-described embodiments 1-5, etc., can be modified in various ways according to design, etc., and can be appropriately combined.

[0170] Furthermore, the combination of dual uplink carrier aggregation that can be handled by multiplexers 1 and 1a is not limited to the combination of the transmit band of Band 25 and the transmit band of Band 66. For example, it can also handle the combination of the transmit band of Band 8 and the transmit band of Band 20, and the combination of the transmit band of Band 3 and the transmit band of Band 20.

[0171] For example, in multiplexers 1 and 1a, multiple phase-shifting circuits 8 are not a necessary component; alternatively, at least one of multiple filters 3 may be connected to the common terminal 2 without passing through the phase-shifting circuit 8.

[0172] Furthermore, although multiplexers 1 and 1a have multiple filters 3, it is sufficient to have at least a first transmitting filter 31 and a second transmitting filter 33. Moreover, the number of multiple filters 3 is not limited to three or four; it can also be five or more.

[0173] Furthermore, although each of the multiple filters 3 in the multiplexers 1 and 1a is an elastic wave filter that utilizes surface acoustic waves, it is not limited to this. For example, it can also be an elastic wave filter that utilizes acoustic boundary waves, plate waves, etc.

[0174] In elastic wave filters, multiple series arm resonators and multiple parallel arm resonators are not limited to SAW resonators; for example, they can also be BAW (Bulk Acoustic Wave) resonators.

[0175] (Way)

[0176] The following methods are disclosed in this specification.

[0177] The multiplexer (1; 1a) involved in the first method has a common terminal (2) and multiple filters (3). The multiple filters (3) are connected to the common terminal (2). Each of the multiple filters (3) has multiple resonators (4). The multiple filters (3) include a first transmitting filter (31) and a second transmitting filter (33). The first transmitting filter (31) has a first passband. The second transmitting filter (33) has a second passband different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. In the multiplexer (1; 1a), the equivalent circuit of a specific resonator (4A) among the multiple resonators (4) in each of the multiple filters (3) is represented by an equivalent resistance (R). m ), equivalent inductor (L) m and equivalent capacitance (C) mWhen representing the series circuit of the first transmitting filter (31) and the parallel circuit of the damping capacitor (C0), if the current flowing through the damping capacitor (C0) is set as the acoustic path current (Iac), then the phase of the acoustic path current (Iac) on the common terminal (2) side of the first transmitting filter (31) at the frequency in the first passband is set as θ1. Tx1 The phase of the acoustic path current (Iac) on the common terminal (2) side of the first transmitting filter (31) at the frequency within the second passband is set to θ2. Tx1 The phase of the acoustic path current (Iac) on the common terminal (2) side of the second transmitting filter (33) at the frequency within the first passband is set to θ1. Tx2 The phase of the acoustic path current (Iac) on the common terminal (2) side of the second transmitting filter (33) at the frequency within the second passband is set to θ2. Tx2 In this case, the multiplexer (1; 1a) satisfies either condition 1 or condition 2. Condition 1 is as follows: |(2·θ1) Tx1 -θ2 Tx1 )-(2·θ1 Tx2 -θ2 Tx2 The second condition is as follows: |(2·θ²) = 180° ± 90°. Tx1 -θ1 Tx1 )-(2·θ2 Tx2 -θ1 Tx2 )|=180°±90°.

[0178] In the multiplexer (1; 1a) involved in the first method, the generation of IMD can be suppressed.

[0179] Regarding the multiplexer (1; 1a) involved in the second method, in the first method, the plurality of filters (3) further include a first receiving filter (32; 32a). The first receiving filter (32; 32a) has a third passband. The third passband includes: a frequency obtained by subtracting a frequency in the second passband from twice the frequency in the first passband; or a frequency obtained by subtracting a frequency in the first passband from twice the frequency in the second passband.

[0180] In the multiplexer (1; 1a) involved in the second method, IMD generated in the third passband can be suppressed, and the decrease in the receiving sensitivity of the first receiving filter (32; 32a) can be suppressed.

[0181] Regarding the multiplexer (1; 1a) involved in the third method, in the second method, regarding the first transmitting filter (31), the density of the acoustic path current on the common terminal (2) side of the first transmitting filter (31) at the frequency within the first passband is set to I1. TX1The density of the acoustic path current on the common terminal (2) side of the first transmitting filter (31) at the frequency within the second passband is set to I2. TX1 The capacitance of the damping capacitor (C0) of the specific resonator (4A) in the first transmitting filter (31) is set to C0. TX1 Regarding the second transmitting filter (33), the density of the acoustic path current on the common terminal (2) side of the second transmitting filter (33) at the frequency within the first passband is set to I1. TX2 The density of the acoustic path current on the common terminal (2) side of the second transmitting filter (33) at the frequency within the second passband is set to I2. TX2 The capacitance of the damping capacitor (C0) of the specific resonator (4A) in the second transmitting filter (33) is set to C0. TX2 Regarding the first receiving filter (32; 32a), the density of the acoustic path current on the common terminal (2) side of the first receiving filter (32; 32a) at the frequency within the first passband is set to I1. RX1 The density of the acoustic path current on the common terminal (2) side of the first receiving filter (32; 32a) at the frequency within the second passband is set to I2. RX1 The capacitance of the damping capacitor (C0) of a specific resonator (4A) in the first receiving filter (32; 32a) is set to C0. RX1 In this case, the multiplexer (1; 1a) satisfies conditions 3 and 4.

[0182] The third condition is as follows:

[0183] (I1 Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 >(I1) Rx1 ) 2 ·(I2 Rx1 )·C0 Rx1 .

[0184] The fourth condition is as follows:

[0185] (I1 Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 >(I1) Rx1 ) 2 ·(I2 Rx1 )·C0 Rx1 .

[0186] The multiplexer (1; 1a) involved in the third method can suppress the generation of IMD.

[0187] Regarding the multiplexer (1; 1a) involved in the fourth method, in the third method, among the multiple filters (3) and multiple resonators (4), a specific resonator (4A) is the one closest to the common terminal (2). Tx1 I2 is the density of the acoustic path current flowing through a specific resonator (4A) of the first transmitting filter (31) at a frequency within the first passband. Tx1 I1 is the density of the acoustic path current flowing through a specific resonator (4A) of the first transmitting filter (31) at a frequency within the second passband. Tx2 It is the density of the acoustic path current flowing through the specific resonator (4A) of the second transmitting filter (33) at a frequency within the first passband. I2 Tx2 It is the density of the acoustic path current flowing at a frequency within the second passband in a specific resonator (4A) of the second transmitting filter (33). In the multiplexer (1; 1a), the IMD of the first transmitting filter (31) and the IMD of the second transmitting filter (33) among the multiple filters (3) are larger than the IMD of the remaining filters among the multiple filters (3). In the multiplexer (1; 1a), (I1 Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 Yes (I1) Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 Values ​​within ±75%, or, (I1) Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 Yes (I1) Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 Values ​​within ±75%.

[0188] The multiplexer (1; 1a) involved in the fourth method can further suppress the generation of IMD.

[0189] Regarding the multiplexer (1; 1a) involved in the fifth method, in the fourth method, the capacitance of the damping capacitor (C0) of a specific resonator (4A) in the first transmitting filter (31) is greater than the capacitance of the damping capacitor (C0) of a specific resonator (4A) in the second transmitting filter (33).

[0190] In the multiplexer (1; 1a) involved in the fifth method, the generation of IMD can be further suppressed.

[0191] Regarding the multiplexer (1; 1a) involved in the sixth method, in the fifth method, the area of ​​a specific resonator (4A) of the first transmitting filter (31) is greater than the area of ​​a specific resonator (4A) of the second transmitting filter (33).

[0192] In the multiplexer (1; 1a) involved in the sixth method, the generation of IMD can be further suppressed.

[0193] Regarding the multiplexer (1a) involved in the seventh method, in the sixth method, a specific resonator (4A) of the first transmitting filter (31) comprises a plurality of segmented resonators (401) connected in series. A specific resonator (4A) of the second transmitting filter (33) comprises a plurality of segmented resonators (401) connected in series. The number of segmented resonators (401) contained in the specific resonator (4A) of the first transmitting filter (31) is greater than the number of segmented resonators (401) contained in the specific resonator (4A) of the second transmitting filter (33).

[0194] In the multiplexer (1a) involved in the seventh method, the generation of IMD can be further suppressed.

[0195] The multiplexer (1; 1a) involved in the eighth method is based on any of the methods from the first to the fourth. In the multiplexer (1; 1a), among the multiple filters (3), a specific resonator (4A) among the multiple resonators (4) is the one closest to the common terminal (2). The first transmitting filter (31) and the second transmitting filter (33) are each trapezoidal filters, and as multiple resonators (4), they include multiple series arm resonators (S11 to S14 and S31 to S34) and multiple parallel arm resonators (P11 to P14 and P31 to P34). In the first transmitting filter (31), a specific resonator (4A) is one of the parallel arm resonators (P14) of the first transmitting filter (31), and in the second transmitting filter (33), a specific resonator (4A) is one of the series arm resonators (S31-S34) of the second transmitting filter (33). In the multiplexer (1; 1a), the capacitance (C0) of the damping capacitor (4A) of the first transmitting filter (31) is greater than the capacitance (C0) of the damping capacitor (4A) of the second transmitting filter (33). Alternatively, in the multiplexer (1; 1a), the area of ​​the specific resonator (4A) of the first transmitting filter (31) is greater than the area of ​​the specific resonator (4A) of the second transmitting filter (33). Alternatively, in the multiplexer (1; 1a), the number of multiple segmented resonators (401) in series with a specific resonator (4A) in the first transmitting filter (31) is greater than the number of multiple segmented resonators (401) in series with a specific resonator (4A) in the second transmitting filter (33). Alternatively, in the multiplexer (1; 1a), each of the multiple resonators (4) in the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) in the second transmitting filter (33) has an IDT electrode (50), and the duty cycle of the IDT electrode (50) of the specific resonator (4A) in the first transmitting filter (31) is different from the duty cycle of the IDT electrode (50) of the specific resonator (4A) in the second transmitting filter (33). Alternatively, in the multiplexer (1; 1a), the plurality of resonators (4) of the first transmitting filter (31) each have an IDT electrode (50), and the plurality of resonators (4) of the second transmitting filter (33) each have an IDT electrode (50), the thickness (H1) of the IDT electrode (50) in a particular resonator (4A) of the first transmitting filter (31) is less than the thickness (H2) of the IDT electrode (50) in a particular resonator (4A) of the second transmitting filter (33).Alternatively, in the multiplexer (1; 1a), each of the multiple resonators (4) of the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) of the second transmitting filter (33) has an IDT electrode (50), wherein the IDT electrode (50) of a particular resonator (4A) of the first transmitting filter (31) is a polycrystalline metal electrode, and the IDT electrode (50) of a particular resonator (4A) of the second transmitting filter (33) is a metal epitaxial layer electrode. Alternatively, in the multiplexer (1; 1a), each of the multiple resonators (4) of the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) of the second transmitting filter (33) has an IDT electrode (50). The material of the IDT electrode (50) of a specific resonator (4A) of the first transmitting filter (31) includes one or more of the following materials: Pt, Mo, Au, Ag, Cu, and W. The content of one or more of the following materials in the IDT electrode (50) of the specific resonator (4A) of the first transmitting filter (31) is higher than the content of the aforementioned one or more materials in the IDT electrode (50) of the specific resonator (4A) of the second transmitting filter (33).

[0196] In the multiplexer (1; 1a) involved in the 8th method, the generation of IMD can be further suppressed.

[0197] The multiplexer (1) involved in the ninth method has a common terminal (2) and multiple filters (3). The multiple filters (3) are connected to the common terminal (2). Each of the multiple filters (3) has multiple resonators (4). The multiple filters (3) include a first transmitting filter (31) and a second transmitting filter (33). The first transmitting filter (31) has a first passband. The second transmitting filter (33) has a second passband that is different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. In each of the multiple filters (3), the resonator closest to the common terminal (2) among the multiple resonators (4) is designated as a specific resonator (4A). The first transmitting filter (31) and the second transmitting filter (33) are each trapezoidal filters, and as multiple resonators (4), they include multiple series arm resonators (S11 to S14 and S31 to S34) and multiple parallel arm resonators (P11 to P14 and P31 to P34). In the first transmitting filter (31), a specific resonator (4A) is one of the parallel arm resonators (P14) of the first transmitting filter (31), and in the second transmitting filter (33), a specific resonator (4A) is one of the series arm resonators (S31-S34) of the second transmitting filter (33). In the multiplexer (1), the capacitance (C0) of the damping capacitor (4A) of the first transmitting filter (31) is greater than the capacitance (C0) of the damping capacitor (4A) of the second transmitting filter (33). Alternatively, in the multiplexer (1), the area of ​​the specific resonator (4A) of the first transmitting filter (31) is greater than the area of ​​the specific resonator (4A) of the second transmitting filter (33). Alternatively, in the multiplexer (1), the number of multiple segmented resonators (401) in series with a specific resonator (4A) in the first transmitting filter (31) is greater than the number of multiple segmented resonators (401) in series with a specific resonator (4A) in the second transmitting filter (33). Alternatively, in the multiplexer (1), each of the multiple resonators (4) in the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) in the second transmitting filter (33) has an IDT electrode (50), and the duty cycle of the IDT electrode (50) of the specific resonator (4A) in the first transmitting filter (31) is different from the duty cycle of the IDT electrode (50) of the specific resonator (4A) in the second transmitting filter (33).Alternatively, in the multiplexer (1), each of the multiple resonators (4) of the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) of the second transmitting filter (33) has an IDT electrode (50), wherein the thickness of the IDT electrode (50) in a particular resonator (4A) of the first transmitting filter (31) is less than the thickness of the IDT electrode (50) in a particular resonator (4A) of the second transmitting filter (33). Alternatively, in the multiplexer (1), each of the multiple resonators (4) of the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) of the second transmitting filter (33) has an IDT electrode (50), wherein the IDT electrode (50) of a particular resonator (4A) of the first transmitting filter (31) is a polycrystalline metal electrode, and the IDT electrode (50) of a particular resonator (4A) of the second transmitting filter (33) is a metal epitaxial layer electrode. Alternatively, in the multiplexer (1), each of the multiple resonators (4) of the first transmitting filter (31) has an IDT electrode (50), and each of the multiple resonators (4) of the second transmitting filter (33) has an IDT electrode (50). The material of the IDT electrode (50) of a specific resonator (4A) of the first transmitting filter (31) includes one or more of the following materials: Pt, Mo, Au, Ag, Cu, and W. The content of one or more of the following materials in the IDT electrode (50) of the specific resonator (4A) of the first transmitting filter (31) is higher than the content of one or more of the following materials in the IDT electrode (50) of the specific resonator (4A) of the second transmitting filter (33).

[0198] In the multiplexer (1) involved in the 9th method, the generation of IMD can be suppressed.

[0199] Regarding the multiplexer (1; 1a) involved in the 10th method, in any of the methods 1 to 9, a first phase-shifting circuit (81) and a second phase-shifting circuit (83) are further provided. The first phase-shifting circuit (81) is connected between the common terminal (2) and the first transmitting filter (31). The second phase-shifting circuit (83) is connected between the common terminal (2) and the second transmitting filter (33). The absolute value of the phase shift amount of the first phase-shifting circuit (81) is greater than the absolute value of the phase shift amount of the second phase-shifting circuit (83).

[0200] In the multiplexer (1; 1a) involved in the 10th method, the generation of IMD can be further suppressed.

[0201] Explanation of reference numerals in the attached figures

[0202] 1, 1a: Multiplexer;

[0203] 2: Common terminal;

[0204] 3: Filter;

[0205] 31: First transmitting filter;

[0206] 310: Path (Serial Arm Path);

[0207] 311: Input terminal;

[0208] 312: Output terminal;

[0209] 32, 32a: First receiving filter;

[0210] 320: Path (tandem arm path);

[0211] 321: Input terminal;

[0212] 322: Output terminal;

[0213] 33: Second transmitting filter;

[0214] 330: Path (tandem arm path);

[0215] 331: Input terminal;

[0216] 332: Output terminal;

[0217] 34, 34a: Second receiving filter;

[0218] 340: Path (tandem arm path);

[0219] 341: Input terminal;

[0220] 342: Output terminal;

[0221] 4: Resonator;

[0222] 4A: A specific resonator;

[0223] 40: Piezoelectric substrate;

[0224] 41: 1st main surface;

[0225] 42: 2nd main surface;

[0226] 43: Sound path;

[0227] 44: Electrical path;

[0228] 401: Segmented resonator;

[0229] 402: Longitudinal Coupled Resonator;

[0230] 403: Longitudinal Coupled Resonator;

[0231] 404: Longitudinal Coupled Resonator;

[0232] 50: IDT electrode;

[0233] 51: First busbar;

[0234] 52: Second busbar;

[0235] 53: The first electrode refers to;

[0236] 54: The second electrode indicates;

[0237] 55: Intersection area;

[0238] 501: Close-fitting layer;

[0239] 502: Main electrode layer;

[0240] 511: Close-fitting layer;

[0241] 512: Main electrode layer;

[0242] 7: Wiring Department;

[0243] 71: First Wiring Section;

[0244] 72: Second wiring section;

[0245] 8: Phase shifting circuit;

[0246] 81: First phase-shifting circuit;

[0247] 82: Third phase-shifting circuit;

[0248] 83: Second phase-shifting circuit;

[0249] 84: Fourth phase shifting circuit;

[0250] D1: First direction;

[0251] D2: Second direction;

[0252] D3: 3rd direction;

[0253] C m Equivalent capacitance;

[0254] C0: Damping capacitor;

[0255] C0 TX1 :capacitance;

[0256] C0 TX2 :capacitance;

[0257] G1, G11, G12: Intervals;

[0258] H1: Thickness;

[0259] H2: Thickness;

[0260] Iac: Current (acoustic path current);

[0261] Ie: Current;

[0262] Iw: Electric current;

[0263] L m Equivalent inductor;

[0264] N11~N14: Nodes;

[0265] N21~N24: Nodes;

[0266] N31~N34: Nodes;

[0267] N41~N44: Nodes;

[0268] P1: Electrode finger spacing;

[0269] P11~P14: Parallel arm resonators;

[0270] P21~P24: Parallel arm resonators;

[0271] P31~P34: Parallel arm resonators;

[0272] P41~P44: Parallel arm resonators;

[0273] R m Equivalent resistance;

[0274] S11~S14: Series arm resonators;

[0275] S21~S24: Series arm resonators;

[0276] S31~S34: Series arm resonators;

[0277] S41~S44: Series arm resonator;

[0278] W1, W11, W12, W55: Width;

[0279] Zac: Impedance;

[0280] Ze: Impedance;

[0281] Zw: Impedance.

Claims

1. A multiplexer, comprising: Common terminal; and Multiple filters, connected to the common terminal, each having multiple resonators, in, The plurality of filters includes: A first transmitting filter, having a first passband; and The second transmitting filter has a second passband that is different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. When the equivalent circuit of a specific resonator among the plurality of filters is represented by a series circuit of equivalent resistance, equivalent inductance, and equivalent capacitance, and a parallel circuit of damping capacitance, if the current flowing through the series circuit is taken as the acoustic path current, then The phase of the acoustic path current on the common terminal side of the first transmitting filter at the frequency within the first passband is set to θ1. Tx1 The phase of the acoustic path current on the common terminal side of the first transmitting filter at the frequency within the second passband is set to θ2. Tx1 The phase of the acoustic path current on the common terminal side of the second transmitting filter at the frequency within the first passband is set to θ1. Tx2 The phase of the acoustic path current on the common terminal side of the second transmitting filter at the frequency within the second passband is set to θ2. Tx2 In the case that the multiplexer satisfies either condition 1 or condition 2, The first condition is as follows: |(2·θ1 Tx1 ―θ2 Tx1 )-(2·θ1 Tx2 ―θ2 Tx2 )|=180°±90°, The second condition is as follows: |(2·θ2 Tx1 ―θ1 Tx1 )-(2·θ2 Tx2 ―θ1 Tx2 )|=180°±90°.

2. The multiplexer according to claim 1, wherein, The plurality of filters further includes: a first receiving filter having a third passband. The third passband includes: The frequency is obtained by subtracting the frequency in the second passband from twice the frequency in the first passband; or, The frequency is obtained by subtracting the frequency in the first passband from twice the frequency in the second passband.

3. The multiplexer according to claim 2, wherein, Regarding the first transmitting filter... Let the density of the acoustic path current on the common terminal side of the first transmitting filter at the frequency within the first passband be I1. TX1 , The density of the acoustic path current on the common terminal side of the first transmitting filter at the frequency within the second passband is set to I2. TX1 , Set the capacitance of the damping capacitor of the specific resonator in the first transmitting filter to C0. TX1 , Regarding the second transmitting filter... The density of the acoustic path current on the common terminal side of the second transmitting filter at the frequency within the first passband is set to I1. TX2 , The density of the acoustic path current on the common terminal side of the second transmitting filter at the frequency within the second passband is set to I2. TX2 , Set the capacitance of the damping capacitor of the specific resonator in the second transmitting filter to C0. TX2 , Regarding the first receiving filter... The density of the acoustic path current on the common terminal side of the first receiving filter at the frequency within the first passband is set to I1. RX1 , The density of the acoustic path current on the common terminal side of the first receiving filter at the frequency within the second passband is set to I2. RX1 , Set the capacitance of the damping capacitor of the specific resonator in the first receiving filter to C0. RX1 In this case, The multiplexer satisfies conditions 3 and 4. The third condition is as follows: (I1 Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 >(I1 Rx1 ) 2 ·(I2 Rx1 )·C0 Rx1 , The fourth condition is as follows: (I1 Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 >(I1 Rx1 ) 2 ·(I2 Rx1 )·C0 Rx1 。 4. The multiplexer according to claim 3, wherein, Among the plurality of filters, the specific resonator among the plurality of resonators is the one closest to the common terminal. The I1 Tx1 It is the density of the acoustic path current flowing through the specific resonator of the first transmitting filter at a frequency within the first passband. The I2 Tx1 It is the density of the acoustic path current flowing through the specific resonator of the first transmitting filter at a frequency within the second passband. The I1 Tx2 It is the density of the acoustic path current flowing through the specific resonator of the second transmitting filter at a frequency within the first passband. The I2 Tx2 It is the density of the acoustic path current flowing through the specific resonator of the second transmitting filter at a frequency within the second passband. In the multiplexer, the IMD of the first transmitting filter and the IMD of the second transmitting filter are greater than the IMD of the remaining filters. In the multiplexer, (I1) Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 Yes (I1) Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 Values ​​within ±75% Or, (I1) Tx2 ) 2 ·(I2 Tx2 )·C0 Tx2 Yes (I1) Tx1 ) 2 ·(I2 Tx1 )·C0 Tx1 Values ​​within ±75%.

5. The multiplexer according to claim 4, wherein, The capacitance of the damping capacitor of the specific resonator in the first transmitting filter is greater than the capacitance of the damping capacitor of the specific resonator in the second transmitting filter.

6. The multiplexer according to claim 5, wherein, The area of ​​the specific resonator of the first transmitting filter is larger than the area of ​​the specific resonator of the second transmitting filter.

7. The multiplexer according to claim 6, wherein, The specific resonator of the first transmitting filter comprises multiple segmented resonators connected in series. The specific resonator of the second transmitting filter comprises multiple segmented resonators connected in series. The specific resonator of the first transmitting filter contains more segmented resonators than the specific resonator of the second transmitting filter.

8. The multiplexer according to any one of claims 1 to 4, wherein, Among the plurality of filters, the specific resonator among the plurality of resonators is the one closest to the common terminal. The first transmitting filter and the second transmitting filter are each trapezoidal filters, and as the plurality of resonators, they include a plurality of series-arm resonators and a plurality of parallel-arm resonators. In the first transmitting filter, the specific resonator is one of the parallel-arm resonators of the first transmitting filter; in the second transmitting filter, the specific resonator is one of the series-arm resonators of the second transmitting filter. In the multiplexer, The damping capacitance of the specific resonator in the first transmitting filter is greater than the damping capacitance of the specific resonator in the second transmitting filter. Alternatively, the area of ​​the specific resonator of the first transmitting filter is larger than the area of ​​the specific resonator of the second transmitting filter. Alternatively, the number of the multiple segmented resonators included in the first transmitting filter and connected in series is greater than the number of the multiple segmented resonators included in the second transmitting filter and connected in series. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The duty cycle of the IDT electrode of the specific resonator in the first transmitting filter is different from the duty cycle of the IDT electrode of the specific resonator in the second transmitting filter. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The thickness of the IDT electrode in the specific resonator of the first transmitting filter is smaller than the thickness of the IDT electrode in the specific resonator of the second transmitting filter. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The IDT electrode of the specific resonator of the first transmitting filter is a polycrystalline metal electrode. The IDT electrode of the specific resonator of the second transmitting filter is an epitaxial layer electrode of metal. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The material of the IDT electrode of the specific resonator of the first transmitting filter includes one or more of the following materials: Pt, Mo, Au, Ag, Cu, and W. The content of one or more materials among Pt, Mo, Au, Ag, Cu, and W in the IDT electrode of the specific resonator of the first transmitting filter is higher than the content of one or more materials in the IDT electrode of the specific resonator of the second transmitting filter.

9. The multiplexer according to any one of claims 1 to 7, wherein, It also has: A first phase-shifting circuit is connected between the common terminal and the first transmitting filter; and The second phase-shifting circuit is connected between the common terminal and the second transmitting filter. The absolute value of the phase shift amount of the first phase shift circuit is greater than the absolute value of the phase shift amount of the second phase shift circuit.

10. A multiplexer, comprising: Common terminal; and Multiple filters, connected to the common terminal, each having multiple resonators, in, The plurality of filters includes: A first transmitting filter, having a first passband; and The second transmitting filter has a second passband that is different from the first passband. The center frequency of the first passband is higher than the center frequency of the second passband. In each of the plurality of filters, the resonator closest to the common terminal is designated as a specific resonator. The first transmitting filter and the second transmitting filter are each trapezoidal filters, and as the plurality of resonators, they include a plurality of series-arm resonators and a plurality of parallel-arm resonators. In the first transmitting filter, the specific resonator is one of the parallel-arm resonators of the first transmitting filter; in the second transmitting filter, the specific resonator is one of the series-arm resonators of the second transmitting filter. In the multiplexer, The damping capacitance of the specific resonator in the first transmitting filter is greater than the damping capacitance of the specific resonator in the second transmitting filter. Alternatively, the area of ​​the specific resonator of the first transmitting filter is larger than the area of ​​the specific resonator of the second transmitting filter. Alternatively, the number of the multiple segmented resonators included in the first transmitting filter and connected in series is greater than the number of the multiple segmented resonators included in the second transmitting filter and connected in series. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The duty cycle of the IDT electrode of the specific resonator in the first transmitting filter is different from the duty cycle of the IDT electrode of the specific resonator in the second transmitting filter. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The thickness of the IDT electrode in the specific resonator of the first transmitting filter is smaller than the thickness of the IDT electrode in the specific resonator of the second transmitting filter. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The IDT electrode of the specific resonator of the first transmitting filter is a polycrystalline metal electrode. The IDT electrode of the specific resonator of the second transmitting filter is an epitaxial layer electrode of metal. Alternatively, each of the plurality of resonators in the first transmitting filter has an IDT electrode, and each of the plurality of resonators in the second transmitting filter has an IDT electrode. The material of the IDT electrode of the specific resonator of the first transmitting filter includes one or more of the following materials: Pt, Mo, Au, Ag, Cu, and W. The content of one or more materials among Pt, Mo, Au, Ag, Cu, and W in the IDT electrode of the specific resonator of the first transmitting filter is higher than the content of one or more materials in the IDT electrode of the specific resonator of the second transmitting filter.

11. The multiplexer according to claim 10, wherein, It also has: A first phase-shifting circuit is connected between the common terminal and the first transmitting filter; and The second phase-shifting circuit is connected between the common terminal and the second transmitting filter. The absolute value of the phase shift amount of the first phase shift circuit is greater than the absolute value of the phase shift amount of the second phase shift circuit.

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