Duplexer and module comprising the same

Abstract

A duplexer includes a piezoelectric substrate, a receive filter formed on the piezoelectric substrate and having a plurality of resonators, and a transmit filter formed on the piezoelectric substrate and having a plurality of resonators, wherein one of the resonators of the receive filter is a multi-modal elastic wave resonator having a capacitance that is more than twice an average capacitance of the other resonators formed on the piezoelectric substrate. Thereby, a duplexer of a multi-modal elastic wave resonator having a passband characteristic closer to a rectangle, and low loss and excellent steepness, and a module having the duplexer are provided.

Description

Technical Field

[0001] This disclosure relates to a duplexer and a module comprising the duplexer. Background Technology

[0002] In recent years, with technological advancements, smartphones and other mobile communication terminals have become significantly smaller and lighter. As a result, miniaturized duplexers are being used in the filters employed in these mobile communication terminals. Furthermore, the number of communication systems capable of simultaneously sending and receiving information has increased dramatically in mobile communication systems, leading to a surge in demand for duplexers.

[0003] Based on the above, the filter at the receiver end of the duplexer will use a multimode resonator with unbalanced-balanced conversion capabilities. Furthermore, with the evolution of mobile communication systems, the requirements for duplexer specifications are becoming increasingly stringent. In other words, compared to existing systems, a multimode resonator that is closer to a rectangular shape and possesses low loss and excellent passband steepness is needed.

[0004] Patent document 1 (Japanese Patent Application Publication No. 2020-43404) exemplifies a technology related to a duplexer.

[0005] However, the technology used in Patent Document 1 cannot provide a duplexer that uses a multimode resonator with excellent passband characteristics. Summary of the Invention

[0006] The purpose of this disclosure is to provide a duplexer for a multimode elastic wave resonator that is closer to a rectangle and has low loss and excellent steep passband characteristics.

[0007] [Methods used to solve problems]

[0008] This disclosure discloses a duplexer comprising: a piezoelectric substrate, a receiving filter formed on the piezoelectric substrate and having a plurality of resonators, and a transmitting filter formed on the piezoelectric substrate and having a plurality of resonators, wherein one of the resonators of the receiving filter is a multimode elastic wave resonator, and the capacitance of the multimode elastic wave resonator is more than twice the average capacitance of the other resonators formed on the piezoelectric substrate.

[0009] In one embodiment of this disclosure, the passband frequency of the receiving filter is lower than the passband frequency of the transmitting filter.

[0010] In one embodiment of this disclosure, the capacitance of the multimodal elastic wave resonator is more than three times the average capacitance of the other resonators of the receiving filter.

[0011] In one embodiment of this disclosure, the multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, wherein the number of pairs of the third IDT electrode is greater than the total number of pairs of the first IDT electrode, the second IDT electrode, the fourth IDT electrode, and the fifth IDT electrode.

[0012] In one embodiment of this disclosure, the multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, wherein the number of logarithms of the first IDT electrode and the number of logarithms of the fifth IDT electrode are the same.

[0013] In one embodiment of this disclosure, the multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, wherein the number of logarithms of the second IDT electrode and the number of logarithms of the fourth IDT electrode are the same.

[0014] In one embodiment of this disclosure, the multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode. The wiring pattern electrically connecting the multimodal elastic wave resonator has a first metal layer, a second metal layer formed on the first metal layer, and an insulator formed between the first metal layer and the second metal layer. The first metal layer is surrounded by the signal line of the third IDT electrode and has an insulating island pattern. The island pattern is electrically connected to the ground line of the second IDT electrode and the ground line of the fourth IDT electrode through the second metal layer.

[0015] In one embodiment of this disclosure, a substrate made of sapphire, silicon, alumina, spinel, crystal, or glass is bonded to the side of the piezoelectric substrate opposite to the side forming the receiving filter and the transmitting filter.

[0016] In one embodiment of this disclosure, the transmitting filter has a plurality of resonators configured in a ladder structure.

[0017] In one embodiment of this disclosure, the area occupied by the receiving filter on the piezoelectric substrate is smaller than the area occupied by the transmitting filter on the piezoelectric substrate.

[0018] One embodiment of this disclosure includes a module comprising the duplexer.

[0019] [The effects of the invention]

[0020] The beneficial effects of the present invention are as follows: According to this disclosure, a duplexer for a multimode elastic wave resonator that is closer to a rectangle and has low loss and excellent steep passband characteristics is provided. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the duplexer in the first embodiment.

[0022] Figure 2 This is a schematic diagram of the structure on the piezoelectric substrate in the first embodiment.

[0023] Figure 3 This is a structural diagram illustrating the resonator.

[0024] Figure 4 This is a graph showing the pass-through characteristics of the receiving filter RxBPF of the duplexer in the first embodiment and the receiving filter of the duplexer in the comparative example.

[0025] Figure 5 This is a graph showing the passband VSWR (Voltage Standing Wave Ratio) characteristics of the receiving filter RxBPF of the duplexer in the first embodiment and the receiving filter of the duplexer in the comparative example.

[0026] Figure 6 The Smith charts representing complex impedances are observed from the input pads of the receiving filter RxBPF of the duplexer in the first embodiment and the receiving filter of the duplexer in the comparative example.

[0027] Figure 7 This is a diagram showing the bandwidth characteristics of the duplexer in the first embodiment.

[0028] Figure 8 This is an explanation Figure 2 A diagram of the structure of the area enclosed by the single-dotted line marked FIG.8.

[0029] Figure 9 This is a cross-sectional view of the module in the second embodiment. Detailed Implementation

[0030] The specific embodiments of this disclosure will now be described with reference to the accompanying drawings. It should be noted that the same or equivalent parts in the various drawings are labeled the same way. The descriptions of these same or equivalent parts will be appropriately simplified or omitted.

[0031] (First Embodiment)

[0032] Figure 1 This is a cross-sectional view of the duplexer 1 in the first embodiment.

[0033] like Figure 1As shown, the duplexer 1 of this first embodiment has a wiring substrate 3 and a piezoelectric substrate 5 mounted on the wiring substrate 3.

[0034] The wiring substrate 3 may be, for example, a multilayer substrate formed of resin, or a low-temperature co-fired ceramic (LTCC) multilayer substrate formed of multiple dielectric layers. Alternatively, the wiring substrate 3 may have multiple external connection terminals 31.

[0035] The piezoelectric substrate 5 is provided with a receiving filter having multiple resonators and a transmitting filter having multiple resonators. The receiving filter and the transmitting filter are bandpass filters configured to allow electrical signals of the desired frequency band to pass through.

[0036] By setting a receiving filter and a transmitting filter on the piezoelectric substrate 5, the duplexer can be miniaturized.

[0037] The piezoelectric substrate 5 can be, for example, a piezoelectric single crystal such as lithium tantalate, lithium niobate, or quartz, or a substrate formed of piezoelectric ceramic.

[0038] The piezoelectric substrate 5 may also be bonded to a support substrate 6. For example, the support substrate 6 may be bonded to the side of the piezoelectric substrate 5 opposite to the side forming the receiving filter and the transmitting filter. The support substrate 6 may be made of, for example, a sapphire substrate, alumina substrate, spinel substrate, crystal, glass or silicon substrate.

[0039] A plurality of electrode pads 9 are provided on the wiring substrate 3. The electrode pads 9 may be made of copper or copper-containing alloys, for example. And the thickness of the electrode pads 9 is, for example, 10 μm to 20 μm.

[0040] The sealing portion 17 is formed to cover the piezoelectric substrate 5. The sealing portion 17 can be formed of an insulator such as a synthetic resin, or it can be made of metal. The synthetic resin can be, for example, epoxy resin, polyimide, etc., but is not limited to these. Preferably, epoxy resin can be used, and the sealing portion 17 is formed using a low-temperature curing process.

[0041] The piezoelectric substrate 5 is mounted on the wiring substrate 3 via bumps 15 using flip-chip bonding technology.

[0042] The bump 15 may be made of gold, for example. The height of the bump 15 may be, for example, 20 μm to 50 μm.

[0043] The electrode pad 9 is electrically connected to the piezoelectric substrate 5 via bumps 15.

[0044] Figure 2This is a schematic diagram of the structure on the piezoelectric substrate 5 in the first embodiment.

[0045] like Figure 2 As shown, a receiving filter RxBPF formed by multiple resonators and a transmitting filter TxBPF formed by multiple resonators are provided on the piezoelectric substrate 5. This allows a duplexer to be provided on the piezoelectric substrate 5.

[0046] like Figure 2 As shown, the multiple resonators forming the receiving filter RxBPF consist of resonators Rx1 to Rx5 and a multimode elastic wave resonator 7. The multiple resonators forming the transmitting filter TxBPF consist of resonators S1 to S5 and resonators P1 to P4.

[0047] Here, the parasitic capacitance of resonator Rx1 is 4.34 pF, the capacitance of resonator Rx2 is 4.18 pF, the capacitance of resonator Rx3 is 3.23 pF, the capacitance of resonator Rx4 is 5.25 pF, the capacitance of resonator Rx5 is 1.13 pF, and the capacitance of the multimode elastic wave resonator 7 is 16.35 pF. It should be noted that the capacitance of the third IDT electrode 73 of the multimode elastic wave resonator 7 (described in detail below) is 9.01 pF. Furthermore, the capacitance of resonator S1 is 2.84pF, the capacitance of resonator S2 is 3.27pF, the capacitance of resonator S3 is 1.89pF, the capacitance of resonator S4 is 2.34pF, the capacitance of resonator S5 is 1.82pF, the capacitance of resonator P1 is 3.48pF, the capacitance of resonator P2 is 6.04pF, the capacitance of resonator P3 is 5.19pF, and the capacitance of resonator P4 is 2.36pF.

[0048] The capacitance of the multimode elastic wave resonator 7 is more than twice the average capacitance of the other resonators (i.e., 3.38 pF). Furthermore, the capacitance of the third IDT electrode 73 is more than twice the average capacitance of the other resonators. This improves impedance matching, providing a low-loss duplexer 1. It also provides a duplexer 1 incorporating a receiver filter with a steep right-shoulder characteristic.

[0049] The capacitance of the multimode elastic wave resonator 7 is more than three times the average capacitance of the other resonators in the receiver filter RxBPF (i.e., 3.63 pF). Furthermore, the capacitance of the third IDT electrode 73 is more than twice the average capacitance of the other resonators in the receiver filter RxBPF. This improves impedance matching and provides a low-loss duplexer. It also provides a duplexer incorporating a receiver filter with a steep right-shoulder characteristic.

[0050] like Figure 2 As shown, the input pad In(Rx) of the receiving filter RxBPF and the output pad Out(Tx) of the transmitting filter TxBPF share a common pad. The output pad Out(Rx) of the receiving filter RxBPF and the input pad In(Tx) of the transmitting filter TxBPF are located at the positions on the piezoelectric substrate 5 where they are furthest apart from each other. Therefore, interference between the receiving filter RxBPF and the transmitting filter TxBPF can be reduced, improving the characteristics of the duplexer 1.

[0051] Furthermore, in the design of setting the receiving filter RxBPF and the transmitting filter TxBPF on the piezoelectric substrate 5, in order to ensure space saving and suppress signals outside the passband, the receiving filter RxBPF can be a multimode elastic wave filter, and in order to ensure power resistance, the transmitting filter TxBPF can be a trapezoidal filter.

[0052] Furthermore, to ensure power resistance, the area occupied by the transmitting filter TxBPF on the piezoelectric substrate 5 can be increased. In other words, preferably, the area occupied by the forming region of the receiving filter RxBPF on the piezoelectric substrate 5 is smaller than the area occupied by the forming region of the transmitting filter TxBPF on the piezoelectric substrate 5.

[0053] The receiving filter RxBPF includes a multimode elastic wave resonator 7. The multimode elastic wave resonator 7 has a first IDT electrode 71, a second IDT electrode 72, a third IDT electrode 73, a fourth IDT electrode 74, and a fifth IDT electrode 75. Reflectors R are respectively arranged adjacent to the first IDT electrode 71 and the fifth IDT electrode 75.

[0054] In this embodiment, the number of logarithms of the first IDT electrode 71 is 22. Furthermore, the number of logarithms of the second IDT electrode 72 is 18. Moreover, the number of logarithms of the third IDT electrode 73 is 96.5. Furthermore, the number of logarithms of the fourth IDT electrode 74 is 18. Furthermore, the number of logarithms of the fifth IDT electrode 75 is 22. In other words, the number of logarithms of the third IDT electrode 73 is greater than the total number of logarithms of the first IDT electrode 71, the second IDT electrode 72, the fourth IDT electrode 74, and the fifth IDT electrode 75.

[0055] The logarithm of the first IDT electrode 71 is 22, the same as that of the fifth IDT electrode 75. Furthermore, the logarithm of the second IDT electrode 72 is 18, the same as that of the fourth IDT electrode 74.

[0056] The piezoelectric substrate 5 has a plurality of wiring patterns 54. The wiring patterns 54 are electrically connected to each of the resonators. The wiring patterns 54 include wiring that constitutes the input pad In (Rx), the input pad In (Tx), the output pad Out (Rx), the output pad Out (Tx), and the ground pad GND.

[0057] The wiring pattern 54 includes a first metal layer and a second metal layer formed on the first metal layer. Figure 2 (Not shown), an insulator is formed between the first metal layer and the second metal layer. Figure 2 (Not shown). The insulator may, for example, be polyimide. The film thickness of the insulator is, for example, 1000 nm.

[0058] The wiring pattern 54 has a three-dimensional wiring portion 58 that is three-dimensionally cross-wired with the first metal layer and the second metal layer through an insulator.

[0059] The resonator and the wiring pattern 54 are formed, for example, by suitable metals or alloys such as silver, aluminum, copper, titanium, and palladium. Furthermore, the aforementioned metal pattern can be composed of a multilayer metal film consisting of multiple stacked metal layers. The thickness of the resonator and the wiring pattern 54 can be, for example, 150 nm to 400 nm.

[0060] The electrical signal input from the input pad In (Rx) passes through the receiving filter RxBPF, and the electrical signal conforming to the expected frequency band is output from the output pad Out (Rx). The electrical signal output from the output pad Out (Rx) is output from the external connection terminal 31 of the wiring substrate 3 through the bump 15 and the electrode pad 9.

[0061] The electrical signal input from the input pad In (Tx) passes through the transmit filter TxBPF, and the electrical signal conforming to the expected frequency band is output from the output pad Out (Tx). The electrical signal output from the output pad Out (Tx) is output from the external connection terminal 31 of the wiring substrate 3 through the bump 15 and the electrode pad 9.

[0062] Figure 3 This is a diagram illustrating the structure of a resonator.

[0063] like Figure 3 As shown, the piezoelectric substrate 5 is provided with an IDT (Interdigital Transducer) 52a capable of exciting elastic surface waves and a reflector R. The IDT 52a has a pair of comb-shaped electrodes 52c facing each other. The comb-shaped electrodes 52c have several electrode fingers 52d and several busbars 52e connecting the electrode fingers 52d. The reflector R is disposed on both sides of the IDT 52a.

[0064] The IDT 52a and the reflector R are, for example, formed of an alloy of aluminum and copper. The IDT 52a and the reflector R are, for example, thin films with a thickness of 150 nm to 400 nm. The IDT 52a and the reflector R can also be other metals, such as titanium, palladium, silver, or suitable metals, or alloys containing the aforementioned metals, and can also be formed from these alloys. Furthermore, the IDT 52a and the reflector R can also be a multilayer metal film structure composed of multiple stacked metal layers.

[0065] Figure 4 This is a schematic diagram showing the transmission characteristics of the receiving filter RxBPF of the duplexer 1 in the first embodiment and the receiving filter of the duplexer in the comparative example.

[0066] The waveforms indicated by solid lines show the pass-through characteristics of the receiving filter RxBPF of the duplexer 1 in the first embodiment. The waveforms indicated by dashed lines show the pass-through characteristics of the receiving filter of the comparative example duplexer. The multimode resonator of the receiving filter of the comparative example has the same number of first to fifth IDT electrodes as the multimode elastic wave resonator 7 (aperture length 31.56λ) of the receiving filter RxBPF of the duplexer 1 in the first embodiment, except that its aperture length is 18.94λ and its capacitance is 9.81pF; all other conditions are the same as those of the receiving filter of the duplexer 1 in the first embodiment.

[0067] like Figure 4 As shown, the first embodiment has excellent low-loss characteristics compared to the comparative example in the passband characteristics, and the excellent attenuation characteristics of the first embodiment can be found in the high frequency range above 820MHz outside the passband.

[0068] Figure 5 This is a graph showing the passband VSWR (Voltage Standing Wave Ratio) characteristics of the receiving filter RxBPF of the duplexer 1 in the first embodiment and the receiving filter of the duplexer in the comparative example.

[0069] The waveforms indicated by solid lines show the VSWR characteristics of the receive filter RxBPF of the duplexer 1 in the first embodiment. The waveforms indicated by dashed lines show the VSWR characteristics of the receive filter of the duplexer in the comparative example.

[0070] like Figure 5 As shown, the passband VSWR characteristic of the receiving filter RxBPF of the duplexer 1 in the first embodiment has excellent low-loss characteristics compared with the comparative example.

[0071] Figure 6The Smith charts representing complex impedances are observed from the input pads In(Rx) of the receiving filter RxBPF of the duplexer 1 in the first embodiment and the input pads of the receiving filter of the duplexer in the comparative example.

[0072] The waveforms indicated by solid lines show the impedance characteristics of the receiving filter RxBPF of the duplexer 1 in the first embodiment. The waveforms indicated by dashed lines show the impedance characteristics of the receiving filter of the duplexer in the comparative example.

[0073] like Figure 6 As shown, it can be seen that the impedance characteristics of the receiving filter RxBPF of the duplexer 1 in the first embodiment are more suitable for impedance matching compared with the comparative example.

[0074] Figure 7 This is a schematic diagram of the frequency band characteristics of the duplexer 1 in the first embodiment.

[0075] like Figure 7 As shown, in the duplexer 1 of the first embodiment, the frequency of the passband Rx of the receiving filter RxBPF is lower than the frequency of the passband Tx of the transmitting filter TxBPF. In a duplexer with the aforementioned frequency relationship, it is required that the receiving filter have a steep suppression characteristic on the high-frequency side of its passband Rx. Generally, it is difficult for multimode filters to steeply suppress the high-frequency side of the passband, but according to this disclosure, even a duplexer with the aforementioned frequency relationship can obtain good passband characteristics in both the passband of the receiving filter and the passband of the transmitting filter.

[0076] Figure 8 This is an explanation Figure 2 A diagram of the structure of the area enclosed by the single-dotted line marked FIG.8.

[0077] like Figure 8 As shown, a first metal layer 54M1 is formed on the piezoelectric substrate 5. Furthermore, the first metal layer 54M1 has an island-shaped pattern IP that is surrounded by and insulated from the signal line L73 of the third IDT electrode 73.

[0078] The piezoelectric substrate 5 also has a ground line GL for the second IDT electrode 72 and a ground line GL for the fourth IDT electrode 74. Furthermore, a second metal layer 54M2 electrically connecting the ground line GL to the island pattern IP is also formed on the piezoelectric substrate 5. An insulator 56 is provided between the second metal layer 54M2 and the signal line L73.

[0079] In this way, the signal line L73, the insulator 56 and the second metal layer 54M2 can form the three-dimensional wiring section 58 of the three-dimensional ground wiring.

[0080] The third IDT electrode 73 of this disclosure suffers from the problem of insulator 56 peeling off due to its large width. Therefore, the inventors have solved the problem of insulator 56 peeling off by dividing the wiring connecting the third IDT electrode 73 into three-dimensional wiring sections and setting up multiple three-dimensional wiring sections.

[0081] And, as Figure 8 As shown, two island-shaped pattern IPs can be formed, and three three-dimensional wiring portions 58 can be formed, or one island-shaped pattern IP can be formed, and two three-dimensional wiring portions 58 can be formed. When forming one island-shaped pattern IP, its length can be increased as needed.

[0082] Here, depending on the thickness and area of ​​the insulator 56, the three-dimensional wiring portion 58 generates parasitic capacitance between the signal line L73 and the second metal layer 54M2 electrically connected to the ground line GL, which may affect the characteristics of the bandpass filter. The thicker the insulator 56, the smaller the parasitic capacitance, but the easier it is for the insulator 56 to peel off. Conversely, the larger the area of ​​the insulator 56, the less likely it is to peel off, but the parasitic capacitance increases.

[0083] Furthermore, although extending the length of the island pattern IP can reduce parasitic capacitance, excessive extension will make the wiring pattern 54 of the signal line L73 elongated, and the problem of increased impedance must be considered.

[0084] According to the structural design of this disclosure, optimized design can be achieved while preventing the spalling of the insulator 56 and the characteristic degradation caused by parasitic capacitance. The structure of this disclosure provides a duplexer with high design freedom and excellent characteristics.

[0085] (Second Embodiment)

[0086] Figure 9 This is a cross-sectional view of module 100 in the second embodiment.

[0087] like Figure 9 As shown, the duplexer 1 is provided on the main surface of the wiring substrate 130. The duplexer 1 may be, for example, a duplexer 1 with the structure described in the first embodiment. The wiring substrate 130 includes a plurality of external connection terminals 131. The external connection terminals 131 can be installed to the motherboard of a predetermined mobile communication terminal.

[0088] An inductor 111 is provided on the main surface of the wiring board 130 to achieve impedance matching. The inductor 111 may be an integrated passive device (IPD). The module 100 seals multiple electronic components, including the duplexer 1, through a sealing portion 117.

[0089] The wiring substrate 130 houses an integrated circuit component (IC). The IC includes a switching circuit (not shown) and a low-noise amplifier.

[0090] Other structures are omitted because they are repeated from the description in the first embodiment.

[0091] According to the above embodiments of this disclosure, a duplexer 1 of a multimode elastic wave resonator 7 that is closer to a rectangle and has low loss and excellent passband characteristics, and a module 100 having said duplexer 1 are provided.

[0092] It should be noted that this disclosure is not limited to the embodiments described above, but also includes all embodiments that can achieve the purpose of this disclosure.

[0093] Furthermore, while at least one embodiment has been described above, it should be understood that various changes, modifications, or improvements will readily conceive of by those skilled in the art. These changes, modifications, or improvements are also part of this disclosure and fall within the scope of the invention. It should be understood that the embodiments of the methods or apparatus described herein are not limited to the architecture and arrangement of the constituent components described above or illustrated in the accompanying drawings. Methods and apparatus can be installed or implemented in other embodiments. The embodiments described are for illustrative purposes only and are not intended to be limiting. Furthermore, the descriptions or terms used in this disclosure are for illustrative purposes only and are not intended to be limiting. The use of "comprising," "possessing," "having," "including," and variations thereof herein means to include the items listed below, their equivalents, and additional items. The term "or," or any term used in the description of "or," can be interpreted as meaning one, more than one, or all of the descriptive terms. References to front, back, left, right, top, bottom, upper, lower, and horizontal and vertical are for convenience of description and are not intended to limit the position and spatial configuration of any constituent component in this invention. Therefore, the above description and accompanying drawings are merely illustrative.

Claims

1. A duplexer, comprising: a piezoelectric substrate, a receiving filter formed on the piezoelectric substrate and having a plurality of resonators, and a transmitting filter formed on the piezoelectric substrate and having a plurality of resonators, wherein, One of the resonators in the receiving filter is a multimode elastic wave resonator, the capacitance of which is more than twice the average capacitance of the other resonators formed on the piezoelectric substrate; and the multimode elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, wherein the number of pairs of the third IDT electrode is greater than the total number of pairs of the first IDT electrode, the second IDT electrode, the fourth IDT electrode, and the fifth IDT electrode.

2. The duplexer according to claim 1, characterized in that: The passband frequency of the receiving filter is lower than that of the transmitting filter.

3. The duplexer according to claim 1, characterized in that: The capacitance of the multimodal elastic wave resonator is more than three times the average capacitance of the other resonators in the receiving filter.

4. The duplexer according to claim 2, characterized in that: The capacitance of the multimodal elastic wave resonator is more than three times the average capacitance of the other resonators in the receiving filter.

5. The duplexer according to any one of claims 1 to 4, characterized in that: The multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, wherein the number of logarithms of the first IDT electrode and the number of logarithms of the fifth IDT electrode are the same.

6. The duplexer according to any one of claims 1 to 4, characterized in that: The multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, wherein the number of logarithms of the second IDT electrode and the number of logarithms of the fourth IDT electrode are the same.

7. The duplexer according to any one of claims 1 to 4, characterized in that: The multimodal elastic wave resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode. The wiring pattern electrically connected to the multimodal elastic wave resonator has a first metal layer, a second metal layer formed on the first metal layer, and an insulator formed between the first metal layer and the second metal layer. The first metal layer is surrounded by the signal line of the third IDT electrode and has an insulating island pattern. The island pattern is electrically connected to the ground line of the second IDT electrode and the ground line of the fourth IDT electrode through the second metal layer.

8. The duplexer according to any one of claims 1 to 4, characterized in that: A substrate made of sapphire, silicon, alumina, spinel, crystal, or glass is bonded to the side of the piezoelectric substrate opposite to the side forming the receiving filter and the transmitting filter.

9. The duplexer according to any one of claims 1 to 4, characterized in that: The transmitting filter has multiple resonators configured in a ladder structure.

10. The duplexer according to any one of claims 1 to 4, characterized in that: The area occupied by the receiving filter on the piezoelectric substrate is smaller than the area occupied by the transmitting filter on the piezoelectric substrate.

11. A module comprising the duplexer according to any one of claims 1 to 10.

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