Multiplexer

Abstract

Provided is a multiplexer in which the heat dissipation performance of a series arm resonator is improved and the power resistance is not susceptible to deterioration. This multiplexer (10) is provided with a transmission filter (1A) and a reception filter (1B). The transmission filter (1A) and the reception filter (1B) each have a plurality of resonators including at least one series arm resonator. A transmission filter (1A) has a piezoelectric substrate (4) and a first series arm resonator unit (series arm resonator unit (S4)) formed on the piezoelectric substrate (4). The reception filter (1B) shares the piezoelectric substrate (4) with the transmission filter (1A), and has a second series arm resonator unit (series arm resonator unit (S11)) formed on the piezoelectric substrate (4). The transmission filter (1A) has an input terminal, an output terminal, and at least one ground terminal. In a circuit configuration of a transmission filter (1A), a path connecting an input terminal and an output terminal is a series arm, a path branching from the series arm to a ground terminal is a parallel arm, and a connection point between the series arm and the parallel arm is a node. The first series arm resonator unit is a group of one series arm resonator or a plurality of series arm resonators connected to each other in series without having a node interposed therebetween in the transmission filter (1A). The reception filter (1B) has an input terminal, an output terminal, and at least one ground terminal. In a circuit configuration of the reception filter (1B), a path connecting an input terminal and an output terminal is a series arm, a path branching from the series arm to a ground terminal is a parallel arm, and a connection point between the series arm and the parallel arm is a node. The second series arm resonator unit is a group of one series arm resonator or a plurality of series arm resonators that are connected to each other in series without having a node therebetween in the reception filter (1B). On the piezoelectric substrate (4), among all the series arm resonators of the transmission filter (1A), any one of the first series arm resonator parts is disposed at a shortest distance from all the resonators of the reception filter (1B). On the piezoelectric substrate (4), among all resonators of the reception filter (1B), any series arm resonator in the second series arm resonator section is disposed at the shortest distance from any series arm resonator in the first series arm resonator section of the transmission filter (1A). The first series arm resonator unit includes a first series arm resonator (series arm resonator (S4b)) having the smallest capacitance among all series arm resonators of the transmission filter (1A). The second series arm resonator unit includes a second series arm resonator (series arm resonator (S11a)) having the maximum capacitance among all series arm resonators of the reception filter (1B).

Description

Technical Field

[0001] The present invention relates to a multiplexer. Background Art

[0002] In the past, multiplexers having a plurality of elastic wave resonators were widely used in filters of portable phones, etc. In the following patent document 1, multiple examples of elastic wave devices as duplexers are disclosed. In the elastic wave device of patent document 1, both a transmission filter and a reception filter are formed on the same piezoelectric substrate. The transmission filter and the reception filter respectively have a plurality of series resonators and a plurality of parallel resonators. Among the distances between the plurality of resonators of the transmission filter and the plurality of resonators of the reception filter, the distance between the series resonators is the shortest.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent Application Publication No. 2019-004264. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] When the duplexer is in operation, the series resonator generates heat. Therefore, when the distance between the series resonators is close, there is a concern that the heat dissipation may be reduced. When the heat dissipation of the series resonator is low, when a high voltage is applied to the series resonator, the series resonator becomes easily damaged. In this way, there is a concern that the power resistance of the duplexer may deteriorate.

[0008] An object of the present invention is to provide a multiplexer capable of improving the heat dissipation of series arm resonators and in which the power handling performance is not easily deteriorated.

[0009] Technical solutions to solve problems

[0010] In a certain broad aspect of a multiplexer according to the present invention, the multiplexer includes a transmission filter and a reception filter, the transmission filter and the reception filter each having a plurality of resonators including at least one series arm resonator, the transmission filter having a piezoelectric substrate and a first series arm resonator section formed on the piezoelectric substrate, the reception filter sharing the piezoelectric substrate with the transmission filter and having a second series arm resonator section formed on the piezoelectric substrate, the transmission filter having an input terminal and an output terminal, and at least one ground terminal, in a circuit structure of the transmission filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, a connection point between the series arm and the parallel arm is a node, the first series arm resonator section is one of the series arm resonators in the transmission filter or a group of a plurality of the series arm resonators connected in series with each other without passing through the node, the reception filter having an input terminal and an output terminal, and at least one ground terminal, in a circuit structure of the reception filter, the input terminal and the output terminal are connected to each other in series. The path connected to the output terminal is a series arm, the path branched from the series arm to the ground terminal is a parallel arm, the connection point of the series arm and the parallel arm is a node, the second series arm resonator unit is one of the series arm resonators in the reception filter or a group of a plurality of series arm resonators connected in series with each other without passing through the node, and on the piezoelectric substrate, among all the series arm resonators of the transmission filter, any of the series arm resonators in the first series arm resonator unit is arranged at the shortest distance from all the resonators of the reception filter. At a distance, on the piezoelectric substrate, among all the resonators of the receiving filter, any series arm resonator in the second series arm resonator section is arranged at the shortest distance from any series arm resonator of the first series arm resonator section of the transmitting filter, the first series arm resonator section includes the first series arm resonator with the smallest electrostatic capacitance among all the series arm resonators of the transmitting filter, and the second series arm resonator section includes the second series arm resonator with the largest electrostatic capacitance among all the series arm resonators of the receiving filter.

[0011] In another broad aspect of the multiplexer according to the present invention, the multiplexer includes a transmission filter and a reception filter, the transmission filter and the reception filter each having a plurality of resonators including at least one series arm resonator, the transmission filter having a piezoelectric substrate and a first series arm resonator section formed on the piezoelectric substrate, the reception filter and the transmission filter share the piezoelectric substrate and have a second series arm resonator section formed on the piezoelectric substrate, the transmission filter has an input terminal and an output terminal, and at least one ground terminal, and in the circuit structure of the transmission filter, a path connecting the input terminal and the output terminal is a series arm, and a path branching from the series arm to the ground terminal is formed. The path connecting the input terminal and the output terminal is a parallel arm, the connection point of the series arm and the parallel arm is a node, the first series arm resonator section is one of the series arm resonators in the transmission filter or a group of multiple series arm resonators connected to each other in series without passing through the node, the reception filter has an input terminal and an output terminal, and at least one ground terminal, in the circuit structure of the reception filter, the path connecting the input terminal and the output terminal is a series arm, the path branching from the series arm to the ground terminal is a parallel arm, the connection point of the series arm and the parallel arm is a node, the second series arm resonator section is one of the series arm resonators in the reception filter or a group of multiple series arm resonators connected to each other in series without passing through the node, A group of a plurality of series-arm resonators connected in series with each other, wherein on the piezoelectric substrate, among all the series-arm resonators of the transmission filter, any of the series-arm resonators in the first series-arm resonator section is arranged at the shortest distance from all the resonators of the reception filter, and on the piezoelectric substrate, among all the resonators of the reception filter, any of the series-arm resonators in the second series-arm resonator section is arranged at the shortest distance from any of the series-arm resonators in the first series-arm resonator section of the transmission filter, and the series-arm resonators of the transmission filter and the reception filter respectively have IDT electrodes, and each of the IDT electrodes includes a plurality of The electrode fingers include a crossing area, when the direction in which the multiple electrode fingers extend is set as the electrode finger extension direction, the area in which adjacent electrode fingers overlap with each other in a direction perpendicular to the electrode finger extension direction is the crossing area, and when the size of the crossing area along the electrode finger extension direction is set as the crossing width, the first series arm resonator portion includes the first series arm resonator among all the series arm resonators of the transmitting filter, the product of the number of the multiple electrode fingers and the crossing width is the smallest, and the second series arm resonator portion includes the second series arm resonator among all the series arm resonators of the receiving filter, the product of the number of the multiple electrode fingers and the crossing width is the largest.

[0012] Effects of the Invention

[0013] According to the multiplexer according to the present invention, the heat dissipation of the series arm resonator can be improved, and the power handling performance is less likely to deteriorate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a circuit diagram of a multiplexer according to a first embodiment of the present invention.

[0015] Figure 2 It is a schematic top view of the multiplexer according to the first embodiment of the present invention.

[0016] Figure 3 It is a diagram showing the attenuation frequency characteristics of the transmission filter in the first embodiment of the present invention.

[0017] Figure 4 It is a diagram showing the attenuation frequency characteristics of the reception filter in the first embodiment of the present invention.

[0018] Figure 5 It is a schematic top view of a multiplexer according to the first comparative example.

[0019] Figure 6 It is a circuit diagram of a multiplexer according to a first comparative example.

[0020] Figure 7 It is a schematic top view of a multiplexer according to the second comparative example.

[0021] Figure 8 It is a circuit diagram of a multiplexer according to the second comparative example.

[0022] Fig. 9 It is a schematic top view of a multiplexer according to the third comparative example.

[0023] Fig.10 It is a plan view showing the electrode structure of the first series arm resonator in the first embodiment of the present invention. DETAILED DESCRIPTION

[0024] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings to clarify the present invention.

[0025] In addition, it should be noted that each embodiment described in this specification is an example, and some structures can be replaced or combined among different embodiments.

[0026] Figure 1 This is a circuit diagram of a multiplexer according to a first embodiment of the present invention.

[0027] like Figure 1As shown, the multiplexer 10 of this embodiment is a duplexer. The multiplexer 10 has a transmission filter 1A and a reception filter 1B. However, the multiplexer 10 is not limited to a duplexer. The multiplexer 10 may also have at least one filter other than the transmission filter 1A and the reception filter 1B. The multiplexer 10 may also be a multiplexer having more than three filters, such as a triplexer or a quadplexer.

[0028] The communication frequency band of the multiplexer 10 is Band 3. The passband of the transmission filter 1A is the transmission frequency band of Band 3, which is 1710 MHz to 1785 MHz. The passband of the reception filter 1B is the reception frequency band of Band 3, which is 1805 MHz to 1880 MHz. However, the communication frequency band of the multiplexer 10 is not limited to the above.

[0029] The multiplexer 10 has a common connection terminal 2. The transmission filter 1A and the reception filter 1B are commonly connected to the common connection terminal 2. That is, the transmission filter 1A and the reception filter 1B share the common connection terminal 2. The common connection terminal 2 is an output terminal of the transmission filter 1A and an input terminal of the reception filter 1B. Furthermore, in the present embodiment, the common connection terminal 2 is an antenna terminal. The antenna terminal is connected to an antenna.

[0030] The transmission filter 1A has a first signal terminal 3A, a plurality of ground terminals, and a plurality of resonators. The first signal terminal 3A is an input terminal of the transmission filter 1A. The ground terminal is a terminal connected to a reference potential. The plurality of resonators are a plurality of series arm resonators and a plurality of parallel arm resonators. The transmission filter 1A is a ladder filter.

[0031] In addition, in the circuit structure of the transmission filter 1A, a series arm B1, a plurality of parallel arms D1 and a plurality of nodes E1 are provided. In more detail, in the circuit structure of the transmission filter 1A, four parallel arms D1 and four nodes E1 are provided. The series arm B1 is a path connecting the first signal terminal 3A as an input terminal and the common connection terminal 2 as an output terminal. In the series arm B1, each series arm resonator is provided. On the other hand, each parallel arm D1 is a path branching from the series arm B1 to each ground terminal. In each parallel arm D1, each parallel arm resonator is provided. On the other hand, the node E1 is a connection point between the series arm B1 and the parallel arm D1.

[0032] In the present embodiment, all of the plurality of series arm resonators and the plurality of parallel arm resonators of the transmission filter 1A are elastic wave resonators, and each elastic wave resonator has an IDT (Interdigital Transducer) electrode.

[0033] The transmission filter 1A has a plurality of series arm resonator sections. The series arm resonator section is one series arm resonator or a group of multiple series arm resonators connected in series with each other without passing through the node E1. More specifically, the series arm resonator section is a portion in which one or more series arm resonators are provided between the input terminal and the node E1, between the nodes E1, or between the node E1 and the output terminal. In addition, as described above, in the transmission filter 1A, the input terminal is the first signal terminal 3A. The output terminal is the common connection terminal 2. The series arm resonator section may also be, for example, a portion including a plurality of split-type series arm resonators.

[0034] The multiple series arm resonator sections of the transmission filter 1A are specifically series arm resonator section S1, series arm resonator section S2, series arm resonator section S3 and series arm resonator section S4. In this embodiment, all series arm resonator sections include multiple series arm resonators that are divided in series. That is, in all series arm resonator sections, multiple divided series arm resonators are connected in series with each other.

[0035] A plurality of series arm resonator sections are connected in series with each other between the first signal terminal 3A and the common connection terminal 2. More specifically, from the first signal terminal 3A side, the series arm resonator section S1, the series arm resonator section S2, the series arm resonator section S3, and the series arm resonator section S4 are connected in sequence.

[0036] The series arm resonator section S4 is the first series arm resonator section in the present invention. The first series arm resonator section includes the first series arm resonator in the present invention. More specifically, the series arm resonator section S4 has a split-type series arm resonator S4a and a series arm resonator S4b. The series arm resonator S4b is the first series arm resonator. Among the electrostatic capacitances of all the series arm resonators of the transmission filter 1A, the electrostatic capacitance of the first series arm resonator is the smallest.

[0037] Furthermore, the series arm resonator section S1 and the series arm resonator section S2 each include three split-type series arm resonators, and the series arm resonator section S3 includes two split-type series arm resonators.

[0038] The transmission filter 1A has a plurality of parallel arm resonator sections. The parallel arm resonator section is one parallel arm resonator or a group of a plurality of parallel arm resonators connected in series in the parallel arm D1. The parallel arm resonator section may also be a section including a plurality of split-type parallel arm resonators. Hereinafter, the series arm resonator section and the parallel arm resonator section may be uniformly recorded as a resonator section.

[0039] The multiple parallel arm resonator parts of the transmission filter 1A are specifically parallel arm resonator parts P1, parallel arm resonator parts P2, parallel arm resonator parts P3 and parallel arm resonator parts P4. In the present embodiment, all the parallel arm resonator parts of the transmission filter 1A include multiple parallel arm resonators divided in series. That is, in all the parallel arm resonator parts, multiple split-type parallel arm resonators are connected in series with each other. More specifically, all the parallel arm resonator parts have two split-type parallel arm resonators, respectively.

[0040] The parallel arm resonator section P1 is connected between the first signal terminal 3A and the ground potential. The parallel arm resonator section P2 is connected between the node E1 between the series arm resonator section S1 and the series arm resonator section S2 and the ground potential. The parallel arm resonator section P3 is connected between the node E1 between the series arm resonator section S2 and the series arm resonator section S3 and the ground potential. The parallel arm resonator section P4 is connected between the node E1 between the series arm resonator section S3 and the series arm resonator section S4 and the ground potential.

[0041] The receiving filter 1B has a second signal terminal 3B, a plurality of ground terminals and a plurality of resonators. The second signal terminal 3B is an output terminal of the receiving filter 1B. On the other hand, as described above, the common connection terminal 2 is an input terminal of the receiving filter 1B. The plurality of resonators are a plurality of series arm resonators and a plurality of parallel arm resonators. The receiving filter 1B is a ladder filter. Similar to the transmitting filter 1A, in the circuit structure of the receiving filter 1B, a series arm B2, a plurality of parallel arms D2 and a plurality of nodes E2 are provided.

[0042] The series arm B2 is a path connecting the common connection terminal 2 as an input terminal and the second signal terminal 3B as an output terminal. In the series arm B2, each series arm resonator is provided. On the other hand, each parallel arm D2 is a path branching from the series arm B2 to each ground terminal. In each parallel arm D2, each parallel arm resonator is provided. On the other hand, the node E2 is the connection point of the series arm B2 and the parallel arm D2. In the circuit structure of the receiving filter 1B, four parallel arms D2 and four nodes E2 are provided. In the present embodiment, the multiple series arm resonators and the multiple parallel arm resonators of the receiving filter 1B are all elastic wave resonators. In addition, in this specification, the definition of the above-mentioned series arm resonator unit and the definition of the parallel arm resonator unit are the same regardless of the type of filter. Specifically, in the receiving filter 1B, the series arm resonator unit is one series arm resonator, or a group of multiple series arm resonators connected in series with each other without passing through the node E2. More specifically, the series arm resonator section is a section between the input terminal and the node E2, between the nodes E2, or between the node E2 and the output terminal, where one or more series arm resonators are provided. The series arm resonator section may also be a section including a plurality of split-type series arm resonators, for example.

[0043] The receiving filter 1B has a plurality of series arm resonator sections. The plurality of series arm resonator sections of the receiving filter 1B are specifically a series arm resonator section S11, a series arm resonator section S12, a series arm resonator section S13, and a series arm resonator section S14. The plurality of series arm resonator sections of the receiving filter 1B are connected in series with each other between the common connection terminal 2 and the second signal terminal 3B. More specifically, from the common connection terminal 2 side, the series arm resonator section S11, the series arm resonator section S12, the series arm resonator section S13, and the series arm resonator section S14 are connected in sequence.

[0044] The series arm resonator section S11 is the second series arm resonator section in the present invention. The second series arm resonator section includes the second series arm resonator in the present invention. More specifically, the series arm resonator section S11 includes a split-type series arm resonator S11a, a series arm resonator S11b, and a series arm resonator S11c. The series arm resonator S11a is the second series arm resonator. Among the electrostatic capacitances of all the series arm resonators of the reception filter 1B, the electrostatic capacitance of the second series arm resonator is the largest.

[0045] Furthermore, each of the series arm resonator section S12 , the series arm resonator section S13 , and the series arm resonator section S14 includes one series arm resonator.

[0046] The receiving filter 1B has a plurality of parallel arm resonator sections. The plurality of parallel arm resonator sections of the receiving filter 1B are specifically a parallel arm resonator section P11, a parallel arm resonator section P12, a parallel arm resonator section P13, and a parallel arm resonator section P14. In the present embodiment, all the parallel arm resonator sections of the receiving filter 1B include one parallel arm resonator.

[0047] The parallel arm resonator section P11 is connected between the node E2 between the series arm resonator section S11 and the series arm resonator section S12 and the ground potential. The parallel arm resonator section P12 is connected between the node E2 between the series arm resonator section S12 and the series arm resonator section S13 and the ground potential. The parallel arm resonator section P13 is connected between the node E2 between the series arm resonator section S13 and the series arm resonator section S14 and the ground potential. The parallel arm resonator section P14 is connected between the second signal terminal 3B and the ground potential.

[0048] In the present embodiment, the resonant frequency of the parallel arm resonator in the parallel arm resonator section P11 is 1783 MHz. The resonant frequency of the parallel arm resonator in the parallel arm resonator section P12 is 1781 MHz. The resonant frequency of the parallel arm resonator in the parallel arm resonator section P13 is 1778 MHz. The resonant frequency of the parallel arm resonator in the parallel arm resonator section P14 is 1774 MHz. Among the plurality of parallel arm resonator sections, the resonant frequency of the parallel arm resonator in the parallel arm resonator section P11 is the highest.

[0049] The circuit structure of the transmission filter 1A and the reception filter 1B is not limited to the above. The transmission filter 1A only needs to have a plurality of resonators including a first series arm resonator. The reception filter 1B only needs to have a plurality of resonators including a second series arm resonator. Furthermore, in the case where the transmission filter 1A and the reception filter 1B are ladder-type filters, the transmission filter 1A and the reception filter 1B only need to have at least one ground terminal and at least one parallel arm resonator, respectively. Alternatively, for example, the transmission filter 1A or the reception filter 1B may also include a longitudinally coupled resonator-type elastic wave filter as a resonator.

[0050] Figure 2 FIG. 1 is a schematic top view of the multiplexer according to the first embodiment. Figure 2 In FIG. 1 , a harmonic oscillator is shown by a simplified diagram with two diagonal lines added to the rectangle.

[0051] A plurality of elastic wave resonators are formed on the piezoelectric substrate 4. On the piezoelectric substrate 4, among the distances between all the resonators of the transmission filter 1A and all the resonators of the reception filter 1B, the distance between the series arm resonator S4b as the first series arm resonator and the series arm resonator S11a as the second series arm resonator is the shortest. However, it is sufficient that the distance between any series arm resonator of the series arm resonator section S4 and any series arm resonator of the series arm resonator section S11 is short. In addition, it is also possible that among the distances between all the resonators of the transmission filter 1A and all the resonators of the reception filter 1B, the distance between any parallel arm resonator of the transmission filter 1A and any series arm resonator of the second series arm resonator section is the shortest.

[0052] In addition, each resonator in this embodiment has Fig.10 The intersection region A shown is described in detail later. In this specification, the distance between resonators refers to the shortest distance between the intersection regions A of the resonators.

[0053] Return to Figure 2 A plurality of ground terminals 14 are provided on the piezoelectric substrate 4. The transmission filter 1A and the reception filter 1B each have a plurality of ground terminals 14. Each ground terminal 14 is connected to a reference potential. In addition, the ground terminal 14 may be connected to a reference potential via an inductor.

[0054] The present embodiment is characterized in that it has the following structures. 1) On the piezoelectric substrate 4, among all the series arm resonators of the transmission filter 1A, any series arm resonator in the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter 1B. 2) On the piezoelectric substrate 4, among all the resonators of the reception filter 1B, any series arm resonator in the second series arm resonator section is arranged at the shortest distance from any series arm resonator in the first series arm resonator section of the transmission filter 1A. 3) The series arm resonator section S4 as the first series arm resonator section includes the series arm resonator S4b as the first series arm resonator having the smallest electrostatic capacitance among all the series arm resonators of the transmission filter 1A. 4) The series arm resonator section S11 as the second series arm resonator section includes the series arm resonator S11a as the second series arm resonator having the largest electrostatic capacitance among all the series arm resonators of the reception filter 1B. Thus, the heat dissipation of the series arm resonator can be improved, and the power resistance of the multiplexer 10 is not easily deteriorated. Figure 3 as well as Figure 4 This indicates that the power handling capability decreases due to the increase in the temperature of the resonator.

[0055] Figure 3 It is a diagram showing the attenuation frequency characteristics of the transmission filter in the first embodiment. Figure 4 It is a diagram showing the attenuation frequency characteristics of the reception filter in the first embodiment.

[0056] Figure 3 In Figure 4 The arrow M1 shown in the figure shows the frequency of the end of the high frequency side in the passband of the transmission filter 1A. The frequency shown by the arrow M1 is set to Hch. Hch is 1785MHz. On the other hand, the arrow M2 shows the frequency of the end of the low frequency side in the passband of the transmission filter 1A. The frequency shown by the arrow M2 is set to Lch. Lch is 1710MHz.

[0057] In the first embodiment, all the resonators are elastic wave resonators. More specifically, all the resonators are surface acoustic wave resonators. In this case, each resonator has a negative frequency temperature coefficient. Therefore, if the temperature of each resonator becomes higher, the resonant frequency of each resonator becomes lower. Therefore, if the temperature of each resonator becomes higher, the frequency band with small insertion loss in the transmission filter 1A moves to the low frequency side. In this state, Lch shown by arrow M2 is also located in the frequency band with small insertion loss. On the other hand, Hch shown by arrow M1 becomes located in the frequency band with large insertion loss. Therefore, the power applied under Hch is easily converted into heat. If the temperature of the electrode in the resonator becomes too high, the resonator will be damaged. In this way, due to the increase in the temperature of the resonator, it becomes easier to generate heat in the resonator, and the power resistance becomes lower.

[0058] Moreover, Hch is located between the resonant frequency and the anti-resonant frequency of the series arm resonator. In the elastic wave resonator, heat is easily generated when power of a frequency between the resonant frequency and the anti-resonant frequency is input. Therefore, the power resistance of the series arm resonator is particularly likely to decrease due to a rise in temperature. In contrast, in the first embodiment, the heat dissipation of the series arm resonator can be improved, and the degradation of the power resistance can be suppressed. The following describes the details of this effect by comparing the first embodiment and the first to third comparative examples.

[0059] In the first to third comparative examples, the arrangement of the plurality of series arm resonator sections and the plurality of parallel arm resonator sections on the circuit is the same as that of the first embodiment. Therefore, the reference numerals of the plurality of series arm resonator sections and the plurality of parallel arm resonator sections in the first to third comparative examples are the same as those in the first embodiment.

[0060] However, the first to third comparative examples are different from the first embodiment in the number of split-type series arm resonators, the total capacitance of the series arm resonator section or the parallel arm resonator section, and the electrode structure on the piezoelectric substrate.

[0061] [Table 1]

[0062]

[0063] Table 1 shows the total electrostatic capacitance of each series arm resonator section of the transmission filter. In Table 1, the result of the first series arm resonator section is surrounded by a thick frame. In the first embodiment, the second comparative example, and the third comparative example, the first series arm resonator section is the series arm resonator section S4. On the other hand, in the first comparative example, the first series arm resonator section is the series arm resonator section S1.

[0064] [Table 2]

[0065]

[0066] Table 2 shows the total electrostatic capacitance of each series arm resonator section of the reception filter. In Table 2, the result of the second series arm resonator section is surrounded by a thick frame. In the first embodiment, the first comparative example, and the third comparative example, the second series arm resonator section is the series arm resonator section S11. On the other hand, in the second comparative example, the second series arm resonator section is the series arm resonator section S14.

[0067] [Table 3]

[0068]

[0069] Table 3 shows the electrostatic capacitance of each series arm resonator in the first series arm resonator section and the second series arm resonator section of the first embodiment. In Table 3, the results of the first series arm resonator and the second series arm resonator are surrounded by a thick frame. Among the electrostatic capacitances of all the series arm resonators of the transmission filter 1A, the electrostatic capacitance of the series arm resonator S4b, which is the first series arm resonator, is the smallest. Among the electrostatic capacitances of all the series arm resonators of the reception filter 1B, the electrostatic capacitance of the series arm resonator S11a, which is the second series arm resonator, is the largest.

[0070] Figure 5 It is a schematic top view of a multiplexer according to the first comparative example. Figure 6 It is a circuit diagram of a multiplexer according to a first comparative example. Figure 7 It is a schematic top view of a multiplexer according to the second comparative example. Figure 8 It is a circuit diagram of a multiplexer according to the second comparative example. Fig. 9 It is a schematic top view of a multiplexer of the third comparative example. In the first to third comparative examples, similarly to the first embodiment, four parallel arms and four nodes are provided in the circuit configurations of the transmission filter and the reception filter, respectively.

[0071] The first comparative example is different from the first embodiment in the following aspects. Figure 5 As shown, in the first comparative example, the series arm resonator of the other series arm resonator section S4 is arranged at a closer distance to the resonator of the reception filter than the series arm resonator section S1 which is the first series arm resonator section. Figure 6 As shown, in the first comparative example, the number of split-type series arm resonators in the series arm resonator section S2 of the transmission filter is 2. The number of split-type series arm resonator sections in the series arm resonator section S4 is 3.

[0072] The second comparative example is different from the first embodiment in the following aspects. Figure 7 As shown, in the second comparative example, the series arm resonator of the other series arm resonator section S11 is arranged at a closer distance to the series arm resonator of the series arm resonator section S4 as the first series arm resonator section than the series arm resonator section S14 as the second series arm resonator section. Figure 8 As shown, in the second comparative example, the number of split-type series arm resonators in the series arm resonator section S11 is two.

[0073] The third comparative example is different from the first embodiment in the following aspects. Fig. 9 As shown, in the third comparative example, the parallel arm resonator in the parallel arm resonator section P11 is arranged at a closer distance to the series arm resonator of the series arm resonator section S4 as the first series arm resonator section than the series arm resonator of the series arm resonator section S11 as the second series arm resonator section.

[0074] The temperatures of each series arm resonator section and each parallel arm resonator section in the first embodiment and the first to third comparative examples are compared. Specifically, the maximum values ​​of the temperatures of each series arm resonator section and each parallel arm resonator section under an ambient temperature of 130°C are compared when a power of 31.5 dBm is input to the first signal terminal. Table 4 shows the maximum values ​​of the temperatures of each series arm resonator section in the transmitting filter. Table 5 shows the maximum values ​​of the temperatures of each parallel arm resonator section in the transmitting filter. Table 6 shows the maximum values ​​of the temperatures of each series arm resonator section in the receiving filter. Table 7 shows the maximum values ​​of the temperatures of each parallel arm resonator section in the receiving filter. In Table 4, the results of the first series arm resonator section are surrounded by a thick frame. In Table 6, the results of the second series arm resonator section are surrounded by a thick frame.

[0075] [Table 4]

[0076]

[0077] [Table 5]

[0078]

[0079] [Table 6]

[0080]

[0081] [Table 7]

[0082]

[0083] As shown in Table 4, the maximum value of the temperature of each series arm resonator section in the transmission filter of the first embodiment is relatively small as a whole. Moreover, in the first embodiment, it can be seen that the maximum value of the temperature of the plurality of series arm resonator sections as a whole is relatively small compared to the first to third comparative examples. This is because of the following reasons. In the first embodiment, among the plurality of resonators of the transmission filter, the series arm resonator of the first series arm resonator section is arranged at the closest distance to the series arm resonator of the second series arm resonator section. Thus, the heat dissipation of the series arm resonator of the transmission filter can be improved. Therefore, as described above, in the first embodiment, the maximum value of the temperature of the plurality of series arm resonator sections as a whole is relatively small. The details are described below.

[0084] In an elastic wave resonator, the smaller the electrostatic capacitance is, the higher the heat generation temperature is when power is input. Furthermore, the total electrostatic capacitance of the first series arm resonator section in the transmission filter 1A of the first embodiment is smaller than the total electrostatic capacitance of each of the other series arm resonator sections in the transmission filter 1A. Therefore, the heat generation temperature in the series arm resonator section S4 as the first series arm resonator section is higher than the heat generation temperature in the other series arm resonator sections.

[0085] Here, in the elastic wave resonator, heat is easily generated when power of a frequency between the resonant frequency and the anti-resonant frequency is input. In contrast, the frequency of the passband of the transmission filter 1A is not easy to overlap with the frequency between the resonant frequency and the anti-resonant frequency of each series arm resonator in the reception filter 1B. Furthermore, even if power of a frequency in the passband of the transmission filter 1A is input, the signal of a frequency in the passband of the reception filter 1B only flows through to a weak degree. Therefore, even if power of a frequency in the passband of the transmission filter 1A is input, heat is not easy to generate in each series arm resonator of the reception filter 1B. In addition, the total of the electrostatic capacitance of the second series arm resonator section is greater than the total of the electrostatic capacitance in each of the other series arm resonator sections of the reception filter 1B. Therefore, heat is less likely to be generated in the second series arm resonator section.

[0086] Among the distances between all the series arm resonator sections of the transmission filter 1A and all the resonator sections of the reception filter 1B, the distance between the first series arm resonator section that is most susceptible to heat generation and the second series arm resonator section that is least susceptible to heat generation in the multiplexer 10 is the shortest. As a result, the heat dissipation in the first series arm resonator section can be effectively improved. Moreover, the heat dissipation of the series arm resonator can be improved as a whole in the multiplexer 10.

[0087] The higher the heating temperature of the elastic wave resonator, the easier it is for the IDT electrode to be degraded due to stress migration when power is applied. Therefore, the power resistance is reduced. In contrast, in the first embodiment, the heat dissipation of the series arm resonator can be improved, and the temperature rise of the series arm resonator can be suppressed. Therefore, as a whole, the power resistance of the multiplexer 10 is not easily degraded.

[0088] Furthermore, the product lifespans were compared between the multiplexers of the first embodiment and the first comparative example. Specifically, a power of 31 dBm was continuously input to the first signal terminal in each multiplexer, and the time until the multiplexer failed was compared. As a result, it was 2800 hours in the first embodiment and 1200 hours in the first comparative example. In this way, it was confirmed that in the first embodiment, the product lifespan was extended to about 2.3 times that of the first comparative example. This is because, in the first embodiment, the heat dissipation of the series arm resonator can be improved, and the power tolerance of the multiplexer as a whole is not easily deteriorated.

[0089] As described above, in the first embodiment, all the resonators are surface acoustic wave resonators. The specific structure of each resonator will be described below.

[0090] Fig.10 FIG. 1 is a top view showing the electrode structure of the first series arm resonator in the first embodiment. Fig.10 In FIG. 1 , wiring and the like connected to the series arm resonator S4b serving as the first series arm resonator are omitted.

[0091] The series arm resonator S4b shares the piezoelectric substrate 4 with the other series arm resonators and the parallel arm resonators. In addition, the piezoelectric substrate 4 is a substrate having piezoelectricity. In the first embodiment, the piezoelectric substrate 4 is a substrate containing only a piezoelectric material. As the piezoelectric material, lithium niobate is used. More specifically, as the piezoelectric material, Y-cut LiNbO3 is used. However, the piezoelectric material is not limited to the above, for example, lithium tantalate, zinc oxide, aluminum nitride, quartz, or PZT (lead zirconate titanate) can also be used.

[0092] In addition, the piezoelectric substrate 4 may also be a laminated substrate including a piezoelectric layer. For the piezoelectric layer, the piezoelectric material described above may be used. In the case where the piezoelectric substrate 4 is a laminated substrate, for example, the piezoelectric layer may be laminated on a supporting substrate. Alternatively, for example, at least one dielectric layer may be laminated between the supporting substrate and the piezoelectric layer.

[0093] like Fig.10 As shown, the series arm resonator S4b has an IDT electrode 5, and a pair of reflectors 6A and 6B. The IDT electrode 5 is provided on the piezoelectric substrate 4. The IDT electrode 5 has a plurality of electrode fingers. By applying an AC voltage to the IDT electrode 5, elastic waves are excited. In the first embodiment, Love waves are excited as the main mode. Here, when the direction in which the plurality of electrode fingers extend is set as the electrode finger extension direction, a pair of reflectors 6A and 6B are provided on both sides of the piezoelectric substrate 4 in a direction perpendicular to the electrode finger extension direction.

[0094] In more detail, the IDT electrode 5 has a first bus bar 7A and a second bus bar 7B, and a plurality of first electrode fingers 8A and a plurality of second electrode fingers 8B as a plurality of electrode fingers. The first bus bar 7A and the second bus bar 7B are opposite to each other. One end of the plurality of first electrode fingers 8A is connected to the first bus bar 7A, respectively. One end of the plurality of second electrode fingers 8B is connected to the second bus bar 7B, respectively. The first electrode finger 8A and the second electrode finger 8B are connected to different potentials from each other. The plurality of first electrode fingers 8A and the plurality of second electrode fingers 8B are interlaced with each other. The IDT electrode 5, the reflector 6A, and the reflector 6B may include a single-layer metal film, or may include a stacked metal film.

[0095] In the following, the first electrode finger 8A and the second electrode finger 8B are sometimes collectively recorded as simply electrode fingers. When viewed from a direction perpendicular to the extending direction of the electrode fingers, the region where adjacent electrode fingers connected to different potentials overlap with each other is the intersection region A of the IDT electrode 5. Elastic waves are excited in the intersection region A. In addition, a group of adjacent electrode fingers connected to different potentials is set as a pair of electrode fingers. When the total number of electrode fingers constituting the intersection region A is set to N, the number of pairs can be derived as N / 2 [pairs]. When N is an odd number, N becomes the value of integer + 0.5 [pairs].

[0096] Figure 1Each series arm resonator and each parallel arm resonator other than the series arm resonator S4b shown in the figure also has an IDT electrode and a pair of reflectors, and has a crossover region, similarly to the series arm resonator S4b. In the first embodiment, each series arm resonator and each parallel arm resonator are surface acoustic wave resonators that are configured to utilize Love waves. However, the main mode utilized in each series arm resonator and each parallel arm resonator in the multiplexer 10 is not limited to Love waves.

[0097] As described above, in an elastic wave resonator, the smaller the electrostatic capacitance, the higher the heating temperature when power is input. On the other hand, the larger the electrostatic capacitance, the lower the heating temperature when power is input. This is because the larger the electrostatic capacitance, the larger the area of ​​the IDT electrode, so the power consumption per unit area of ​​the IDT electrode becomes smaller. In addition, the larger the electrostatic capacitance, the lower the impedance, so the power consumption itself is also easy to become smaller. As a result of these, the heat caused by the application of power can be suppressed.

[0098] In addition, the electrostatic capacitance is mainly proportional to the product of the number of pairs of multiple electrode fingers and the cross width in the IDT electrode. The so-called cross width is the dimension of the cross region along the extension direction of the electrode fingers. The larger the electrostatic capacitance, the larger the product of the number of pairs of multiple electrode fingers and the cross width, and the larger the area of ​​the IDT electrode. Therefore, in the first embodiment, among the products of the number of pairs of multiple electrode fingers and the cross width in all the series arm resonators of the transmitting filter 1A, the product of the number of pairs of multiple electrode fingers and the cross width in the first series arm resonator of the first series arm resonator part is the smallest. On the other hand, among the products of the number of pairs of multiple electrode fingers and the cross width in all the series arm resonators of the receiving filter 1B, the product of the number of pairs of multiple electrode fingers and the cross width in the second series arm resonator of the second series arm resonator part is the largest.

[0099] By increasing the area of ​​the IDT electrode, the electrostatic capacitance increases and the heating temperature decreases. However, increasing the area of ​​all IDT electrodes will lead to a larger multiplexer. On the other hand, in the past, in order to improve heat dissipation, the number of bumps used to bond the piezoelectric substrate to the packaging substrate, etc. was increased. However, in this case, the device as a whole, including the packaging substrate and the bumps, is also enlarged.

[0100] In contrast, Figure 2As shown, in the first embodiment, the series arm resonator section S4 having the smallest total electrostatic capacitance in the transmission filter 1A and the series arm resonator section S11 having the largest total electrostatic capacitance in the reception filter 1B are adjacent to each other. More specifically, among the distances between the multiple series arm resonators of the transmission filter 1A and the multiple resonators of the reception filter 1B, the distance between the series arm resonator S4b of the series arm resonator section S4 and the series arm resonator S11a of the series arm resonator section S11 is the shortest. Thus, even if the area of ​​the IDT electrode in each series arm resonator of the series arm resonator section S4 is reduced, as described above, the heat dissipation can be effectively improved. Therefore, the multiplexer 10 will not be enlarged, and the deterioration of the power resistance can be suppressed.

[0101] As shown in Table 6, in the first embodiment, the temperature of the series arm resonator section S11 as the second series arm resonator section is relatively high. This is because the heat from the series arm resonator section S4 as the first series arm resonator section is transferred to the series arm resonator section S11.

[0102] In addition, if Figure 2 As shown in FIG. 1 , the series arm resonator section S2 of the transmission filter 1A is surrounded by other resonators. Therefore, among the plurality of series arm resonator sections of the transmission filter 1A, the heat dissipation of the series arm resonator section S2 is particularly low. Figure 5 The same is true for the first comparative example shown. Furthermore, in the first comparative example, the total of the electrostatic capacitance in the series arm resonator section S2 is relatively small. Therefore, the temperature in the series arm resonator section S2 becomes the highest among the plurality of series arm resonator sections.

[0103] In contrast, in the first embodiment, as shown in Table 1, the total electrostatic capacitance of the series arm resonator section S2 is relatively large. Therefore, the heat generation temperature in the series arm resonator section S2 is low. Thus, the temperature of the series arm resonator section S2 can be reduced. Therefore, as the multiplexer 10 as a whole, the degradation of the power resistance can be effectively suppressed.

[0104] In addition, in the first comparative example, Figure 5 As shown, the number of series arm resonators in the series arm resonator section S4 is 3, and the area of ​​each series arm resonator is relatively large. On the other hand, the number of series arm resonators in the series arm resonator section S2 is 2, and the area of ​​each series arm resonator is relatively small. On the piezoelectric substrate 4, the area occupied by the series arm resonator section S4 is large, and the area occupied by the series arm resonator section S2 becomes smaller accordingly. As a result, the temperature of the series arm resonator section S2 is high. Moreover, heat is also easily transmitted from the series arm resonator section S2 to the parallel arm resonator section P3 that is adjacent to the series arm resonator section S2 on the piezoelectric substrate 4 and connected by wiring. Therefore, as shown in Table 5, the temperature of the parallel arm resonator section P3 becomes high.

[0105] In contrast, in the first embodiment, the area occupied by the series arm resonator section S4 is small in the piezoelectric substrate 4, and the area occupied by the series arm resonator section S2 can be increased accordingly. More specifically, the number of series arm resonators in the series arm resonator section S2 is 3, and the area of ​​each series arm resonator is large. As a result, the temperature can be suppressed from rising in the series arm resonator section S2 having relatively low heat dissipation. Along with this, the temperature of the parallel arm resonator section P3 can also be suppressed from rising.

[0106] Furthermore, in the first embodiment and the first comparative example, the combined capacitance of all the series arm resonator parts in the transmission filter is almost the same. Thus, in the first embodiment, although the transmission filter has almost the same pass characteristics as the first comparative example, the temperature of each series arm resonator part can be suppressed from rising, and the degradation of the power resistance can be suppressed. Furthermore, it is not easy to cause the multiplexer to be large-scale.

[0107] In the second comparative example, Figure 7 As shown, the series arm resonator section S11 among the multiple series arm resonator sections of the receiving filter is arranged at the closest distance to the series arm resonator section S4 which is the first series arm resonator section. In the second comparative example, as shown in Table 2, the total electrostatic capacitance of the series arm resonator section S11 is small. Therefore, the heating temperature of the series arm resonator section S11 itself is relatively high. Therefore, the heat dissipation of the series arm resonator section S4 becomes lower. As shown in Tables 4 and 6, in the second comparative example, the temperature becomes high in both the series arm resonator section S4 and the series arm resonator section S11.

[0108] In contrast, in the first embodiment, as described above, among the plurality of series arm resonator sections of the reception filter 1B, the series arm resonator section S11 having the largest total capacitance is arranged at the closest distance to the series arm resonator section S4. Therefore, the heat dissipation of the series arm resonator section S4 can be effectively improved.

[0109] In the third comparative example, Fig. 9 As shown, the parallel arm resonator in the parallel arm resonator section P11 is arranged at a closer distance to the series arm resonator of the series arm resonator section S4 as the first series arm resonator section than the series arm resonator of the series arm resonator section S11 as the second series arm resonator section. The heat generation temperature in the parallel arm resonator of the receiving filter is higher than the heat generation temperature in the series arm resonator of the receiving filter. Therefore, in the third comparative example, the heat dissipation of the series arm resonator section S4 becomes lower. As shown in Tables 4 and 7, in the third comparative example, the temperature becomes higher in both the series arm resonator section S4 and the parallel arm resonator section P11.

[0110] In contrast, in the first embodiment, among all the resonators of the reception filter 1B, the series arm resonator of the series arm resonator section S11 as the second series arm resonator section is arranged at the closest distance to the series arm resonator of the series arm resonator section S4. Furthermore, as described above, even if power of a frequency in the passband of the transmission filter 1A is input, heat is not easily generated in the series arm resonator section S11. Therefore, the heat dissipation of the series arm resonator section S4 can be effectively improved.

[0111] In addition, each series arm resonator and each parallel arm resonator of the multiplexer 10 may be a BAW (Bulk Acoustic Wave) element. The electrostatic capacitance of a BAW element is proportional to the facing area of ​​the excitation electrodes.

[0112] A preferred configuration in the first embodiment is described below.

[0113] like Figure 2 As shown, preferably, on the piezoelectric substrate 4, among all the resonators of the transmission filter 1A, any series arm resonator in the series arm resonator section S4 as the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter 1B. That is, preferably, not only compared to all the series arm resonators of the transmission filter 1A, but also compared to all the parallel arm resonators of the transmission filter 1A, the series arm resonator of the first series arm resonator section is arranged at the closest distance to all the series arm resonators and parallel arm resonators of the reception filter 1B. In this case, the distance between the series arm resonator in the first series arm resonator section of the transmission filter 1A and the series arm resonator in the second series arm resonator section of the reception filter 1B can be more reliably shortened. Therefore, the heat dissipation of the series arm resonator of the transmission filter 1A can be more reliably improved.

[0114] As described above, the series arm resonator S4b in the series arm resonator section S4 is the first series arm resonator in the present invention. Among the electrostatic capacitances of all the series arm resonators in the transmission filter 1A, the electrostatic capacitance of the first series arm resonator is the smallest. The series arm resonator S11a in the series arm resonator section S11 is the second series arm resonator in the present invention. Among the electrostatic capacitances of all the series arm resonators in the reception filter 1B, the electrostatic capacitance of the second series arm resonator is the largest. Preferably, among the distances between the plurality of series arm resonators in the first series arm resonator section and the plurality of series arm resonators in the second series arm resonator section, the distance between the first series arm resonator and the second series arm resonator is the shortest. Thus, the heat dissipation of the first series arm resonator having the highest heat generation temperature in the transmission filter 1A can be further improved. Therefore, as a whole, the degradation of the power resistance of the multiplexer 10 can be further suppressed.

[0115] Among all the parallel arm resonators of the receiving filter 1B, the parallel arm resonator in the parallel arm resonator section P11 is arranged on the piezoelectric substrate 4 at the shortest distance from the series arm resonator in the first series arm resonator section of the transmitting filter 1A. In this case, the parallel arm resonator section P11 preferably includes the parallel arm resonator with the largest electrostatic capacitance among all the parallel arm resonators of the receiving filter 1B. Thus, heat is not easily generated in the parallel arm resonator section P11. The distance between the parallel arm resonator in the parallel arm resonator section P11 and the series arm resonator in the series arm resonator section S4 as the first series arm resonator section is short as described above, so the heat dissipation of the series arm resonator section S4 can be further improved.

[0116] However, in the first embodiment, the parallel arm resonator section P11 includes one parallel arm resonator. Therefore, it is preferable that the electrostatic capacitance of the parallel arm resonator is the largest among the electrostatic capacitances of all the parallel arm resonators of the reception filter 1B.

[0117] More preferably, among the distances between the first series arm resonator and all the parallel arm resonators of the receiving filter 1B, the distance between the first series arm resonator and the parallel arm resonator with the largest electrostatic capacitance among all the parallel arm resonators of the receiving filter 1B is the shortest. Thus, the heat dissipation of the first series arm resonator can be more effectively improved.

[0118] Preferably, the center frequency of the passband of the reception filter 1B is higher than the center frequency of the passband of the transmission filter 1A. In this case, the frequency between the resonant frequency and the anti-resonant frequency of each series arm resonator in the reception filter 1B is not likely to overlap with the frequency of the passband of the transmission filter 1A. For example, even if Figure 3 In Figure 4 When power is applied at the frequency Hch indicated by the arrow M1 in FIG. 1 , heat is not easily generated in each series arm resonator of the reception filter 1B. Therefore, heat is easily dissipated from the first series arm resonator section of the transmission filter 1A to the second series arm resonator section of the reception filter 1B. Therefore, the heat dissipation of the first series arm resonator section can be more reliably improved.

[0119] In addition, when the passbands of the transmission filter 1A and the reception filter 1B are close to each other, the frequency between the resonance frequency and the anti-resonance frequency of the parallel arm resonator in the reception filter 1B is likely to overlap with the passband of the transmission filter 1A. For example, when the difference between the end of the high-frequency side of the passband of the transmission filter 1A and the end of the low-frequency side of the passband of the reception filter 1B is less than 2% of the center frequency of the passband in the transmission filter 1A, the above-mentioned overlap is particularly likely to occur. In this case, heat is likely to be generated in the parallel arm resonator of the reception filter 1B. Therefore, the structure of the first embodiment in which the series arm resonator in the first series arm resonator section of the transmission filter 1A and the series arm resonator in the second series arm resonator section of the reception filter 1B are close to each other is particularly suitable.

[0120] As described above, in the first embodiment, among all the parallel arm resonators of the reception filter 1B, the parallel arm resonators in the parallel arm resonator section P11 are arranged at the shortest distance from the series arm resonators in the first series arm resonator section of the transmission filter 1A on the piezoelectric substrate 4. In this case, the parallel arm resonator section P11 preferably includes the parallel arm resonator having the highest resonance frequency among all the parallel arm resonators of the reception filter 1B.

[0121] In the first embodiment, the passband of the receiving filter 1B is located at a position closer to the high-frequency side than the passband of the transmitting filter 1A. Therefore, the higher the resonant frequency of the parallel arm resonator in the receiving filter 1B, the easier it is for the resonant frequency to move away from the passband of the transmitting filter 1A to the high-frequency side. Moreover, the frequency between the resonant frequency and the anti-resonant frequency of the parallel arm resonator is not easy to overlap with the passband of the transmitting filter 1A. Therefore, even if power at the frequency of the passband of the transmitting filter 1A is applied, the parallel arm resonator is not easy to generate heat. The distance between the parallel arm resonator in the parallel arm resonator section P11 and the series arm resonator in the first series arm resonator section is short as described above, so the heat dissipation of the first series arm resonator section can be further improved.

[0122] More preferably, among the distances between the first series arm resonator and all the parallel arm resonators of the receiving filter 1B, the distance between the first series arm resonator and the parallel arm resonator with the highest resonance frequency among all the parallel arm resonators of the receiving filter 1B is the shortest. Thus, the heat dissipation of the first series arm resonator can be more effectively improved.

[0123] The second series arm resonator section of the receiving filter 1B preferably includes a plurality of split-type series arm resonators connected in series with each other. As a result, the total area of ​​the IDT electrodes in the second series arm resonator section can be expanded, and the total electrostatic capacitance can be increased. Therefore, the heating temperature in the second series arm resonator section can be reduced. Therefore, the heat dissipation in the first series arm resonator section can be effectively improved. In addition, the power consumption per unit area in the second series arm resonator section can be reduced, so the power resistance of each series arm resonator in the second series arm resonator section is not easily deteriorated.

[0124] In the first embodiment, the number of series arm resonators in the first series arm resonator section, i.e., the series arm resonator section S4, of the transmitting filter 1A is 2. The number of series arm resonators in the second series arm resonator section, i.e., the series arm resonator section S11 of the receiving filter 1B is 3. As such, the number of series arm resonators in the second series arm resonator section is preferably greater than the number of series arm resonators in the first series arm resonator section. Thus, the electrostatic capacitance in the second series arm resonator section can be more reliably increased. In addition, the area of ​​the first series arm resonator section can be more reliably reduced. Therefore, the multiplexer 10 will not be enlarged, and the heat dissipation of the first series arm resonator section can be more reliably improved, and as the multiplexer 10 as a whole, the degradation of the power resistance can be more reliably suppressed.

[0125] In addition, the first series arm resonator section may include one series arm resonator, and the number of series arm resonators in the second series arm resonator section may be greater than the number of series arm resonators in the first series arm resonator section. However, the first series arm resonator section preferably includes a plurality of split-type series arm resonators connected in series with each other. Thus, the heat generation temperature in the first series arm resonator section itself can also be reduced. Therefore, the power resistance is less likely to deteriorate.

[0126] like Figure 1 As shown, the transmission filter 1A and the reception filter 1B are commonly connected to the common connection terminal 2. Preferably, among all the resonators of the transmission filter 1A, any series arm resonator in the first series arm resonator section of the transmission filter 1A is arranged at a position closest to the common connection terminal 2. Thus, it is easy to dissipate heat from the first series arm resonator section to the outside via the common connection terminal 2. Therefore, the heat dissipation of the first series arm resonator section can be effectively improved.

[0127] In this case, preferably, among all the resonators of the reception filter 1B, any series arm resonator in the second series arm resonator section of the reception filter 1B is arranged at a position closest to the common connection terminal 2. Thus, it is easy to shorten the distance between the second series arm resonator section and the first series arm resonator section, and the heat dissipation of the first series arm resonator section can be more reliably improved.

[0128] More preferably, among all the resonators of the transmission filter 1A, the series arm resonator S4b as the first series arm resonator is arranged at a position closest to the common connection terminal 2. More preferably, among all the resonators of the reception filter 1B, the series arm resonator S11a as the second series arm resonator is arranged at a position closest to the common connection terminal 2. Thus, the heat dissipation of the first series arm resonator can be further improved.

[0129] like Figure 2 As shown, the multiplexer 10 has a wiring electrode 9. The wiring electrode 9 is connected to the common connection terminal 2. Through the wiring electrode 9, the series arm resonator in the transmission filter 1A arranged at the position closest to the common connection terminal 2 and the series arm resonator in the reception filter 1B arranged at the position closest to the common connection terminal 2 are connected. Moreover, the series arm resonator of the transmission filter 1A and the series arm resonator of the reception filter 1B connected by the wiring electrode 9 are preferably the series arm resonator in the first series arm resonator section and the series arm resonator in the second series arm resonator section. More preferably, the first series arm resonator and the second series arm resonator are connected by the wiring electrode 9. The wiring electrode 9 contains metal, so the thermal conductivity of the wiring electrode 9 is higher than the thermal conductivity of the piezoelectric substrate 4. Therefore, it is easy to dissipate heat from the first series arm resonator section to the second series arm resonator section. Therefore, the heat dissipation of the first series arm resonator section can be more effectively improved.

[0130] It is preferable to use Al as a material of the wiring electrode 9. This can more reliably improve the thermal conductivity of the wiring electrode 9.

[0131] The transmission filter 1A and the reception filter 1B are preferably ladder filters. In this case, compared with a case where the transmission filter 1A or the reception filter 1B includes a longitudinally coupled resonator elastic wave filter, the power handling performance of the multiplexer 10 as a whole is less likely to deteriorate.

[0132] Hereinafter, examples of aspects of the multiplexer according to the present invention will be summarized and described.

[0133] <1> A multiplexer includes a transmission filter and a reception filter, wherein the transmission filter and the reception filter each have a plurality of resonators including at least one series arm resonator, the transmission filter having a piezoelectric substrate and a first series arm resonator section formed on the piezoelectric substrate, the reception filter and the transmission filter share the piezoelectric substrate and have a second series arm resonator section formed on the piezoelectric substrate, the transmission filter having an input terminal and an output terminal, and at least one ground terminal, in a circuit structure of the transmission filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, a connection point between the series arm and the parallel arm is a node, the first series arm resonator section is one of the series arm resonators in the transmission filter or a group of a plurality of series arm resonators connected in series with each other without passing through the node, the reception filter having an input terminal and an output terminal, and at least one ground terminal, in a circuit structure of the reception filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, a connection point between the series arm and the parallel arm is a node, the second series arm resonator section is one of the series arm resonators in the reception filter or a group of a plurality of the series arm resonators connected in series with each other without passing through the node, on the piezoelectric substrate, among all the series arm resonators of the transmission filter, any of the series arm resonators in the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter, on the piezoelectric substrate, among all the resonators of the reception filter, any of the series arm resonators in the second series arm resonator section is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator section of the transmission filter, the first series arm resonator section includes the first series arm resonator with the smallest electrostatic capacitance among all the series arm resonators of the transmission filter, and the second series arm resonator section includes the second series arm resonator with the largest electrostatic capacitance among all the series arm resonators of the reception filter.

[0134] <2> A multiplexer includes a transmission filter and a reception filter, wherein the transmission filter and the reception filter respectively have a plurality of resonators including at least one series arm resonator, the transmission filter has a piezoelectric substrate and a first series arm resonator section formed on the piezoelectric substrate, the reception filter and the transmission filter share the piezoelectric substrate and have a second series arm resonator section formed on the piezoelectric substrate, the transmission filter has an input terminal and an output terminal, and at least one ground terminal, in the circuit structure of the transmission filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, and the The connection point between the series arm and the parallel arm is a node, the first series arm resonator section is one of the series arm resonators in the transmission filter or a group of multiple series arm resonators connected in series without passing through the node, the reception filter has an input terminal and an output terminal, and at least one ground terminal, in the circuit structure of the reception filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, the connection point between the series arm and the parallel arm is a node, the second series arm resonator section is one of the series arm resonators in the reception filter or a group of multiple series resonators connected in series without passing through the node The group of series arm resonators, on the piezoelectric substrate, among all the series arm resonators of the transmission filter, any series arm resonator in the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter, and on the piezoelectric substrate, among all the resonators of the reception filter, any series arm resonator in the second series arm resonator section is arranged at the shortest distance from any series arm resonator in the first series arm resonator section of the transmission filter, and the series arm resonators of the transmission filter and the reception filter respectively have IDT electrodes, and each of the IDT electrodes includes a plurality of electrode fingers connected in parallel. And it includes an intersection area, when the direction in which the multiple electrode fingers extend is set as the electrode finger extension direction, the area in which adjacent electrode fingers overlap with each other in the direction perpendicular to the electrode finger extension direction is the intersection area, and when the size of the intersection area along the electrode finger extension direction is set as the intersection width, the first series arm resonator part includes the first series arm resonator among all the series arm resonators of the transmitting filter, the product of the number of the multiple electrode fingers and the intersection width is the smallest, and the second series arm resonator part includes the second series arm resonator among all the series arm resonators of the receiving filter, the product of the number of the multiple electrode fingers and the intersection width is the largest.

[0135] <3> according to <1> or <2> In the multiplexer, the transmission filter and the reception filter share a common connection terminal, and the common connection terminal is the output terminal of the transmission filter and the input terminal of the reception filter.

[0136] <4> according to <1> ~ <3> The multiplexer as described in any one of the above, wherein the plurality of resonators of the transmitting filter include at least one parallel arm resonator, and on the piezoelectric substrate, among all the resonators of the transmitting filter, any of the series arm resonators in the first series arm resonator section is arranged at the shortest distance from all the resonators of the receiving filter.

[0137] <5> according to <1> ~ <4> A multiplexer as described in any one of the preceding claims, wherein the plurality of resonators of the receiving filter include at least one parallel arm resonator, the receiving filter has a parallel arm resonator section formed on the piezoelectric substrate, the parallel arm resonator section is one parallel arm resonator, or a group of a plurality of parallel arm resonators connected in series with each other in the parallel arm, including the parallel arm resonator section of the following parallel arm resonators including the parallel arm resonator with the largest electrostatic capacitance among all the parallel arm resonators of the receiving filter: on the piezoelectric substrate, among all the parallel arm resonators of the receiving filter, the parallel arm resonator is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator section of the transmitting filter.

[0138] <6> according to <1> ~ <5> The multiplexer as described in any one of the preceding claims, wherein a center frequency of a passband of the receive filter is higher than a center frequency of a passband of the transmit filter.

[0139] <7> according to <6> The multiplexer, wherein the multiple resonators of the receiving filter include at least one parallel arm resonator, the receiving filter has a parallel arm resonator unit formed on the piezoelectric substrate, the parallel arm resonator unit is one parallel arm resonator, or a group of multiple parallel arm resonators connected in series with each other in the parallel arm, including the parallel arm resonator unit of the following parallel arm resonators including the parallel arm resonator with the highest resonance frequency among all the parallel arm resonators of the receiving filter: on the piezoelectric substrate, among all the parallel arm resonators of the receiving filter, the parallel arm resonator is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator unit of the transmitting filter.

[0140] <8> according to <1> ~ <7> In the multiplexer described in any one of the preceding claims, the second series arm resonator section of the reception filter includes a plurality of split-type series arm resonators connected in series with one another.

[0141] <9> according to <8> The multiplexer described above, wherein the number of the series arm resonators in the second series arm resonator section of the reception filter is greater than the number of the series arm resonators in the first series arm resonator section of the transmission filter.

[0142] <10> according to <8> or <9> The multiplexer, wherein the first series arm resonator section of the transmitting filter includes a plurality of split-type series arm resonators connected in series with each other, and among the distances between the plurality of series arm resonators in the first series arm resonator section and the plurality of series arm resonators in the second series arm resonator section, the distance between the first series arm resonator in the first series arm resonator section of the transmitting filter and the second series arm resonator in the second series arm resonator section of the receiving filter is the shortest.

[0143] <11> according to <1> ~ <9> In the multiplexer described in any one of the preceding claims, the first series arm resonator section of the transmission filter includes a plurality of split-type series arm resonators connected in series with one another.

[0144] <12> according to <1> ~ <11> The multiplexer as described in any one of the above, wherein the multiplexer further comprises: a common connection terminal to which the transmitting filter and the receiving filter are commonly connected; and a wiring electrode connected to the common connection terminal, wherein among all the resonators of the transmitting filter, any of the series arm resonators in the first series arm resonator section of the transmitting filter is arranged at a position closest to the common connection terminal, and among all the resonators of the receiving filter, any of the series arm resonators in the second series arm resonator section of the receiving filter is arranged at a position closest to the common connection terminal, and the series arm resonators in the transmitting filter arranged at the position closest to the common connection terminal and the series arm resonators in the receiving filter arranged at the position closest to the common connection terminal are connected via the wiring electrode.

[0145] <13> according to <12> The multiplexer, wherein, among all the resonators of the transmitting filter, the first series arm resonator in the first series arm resonator section of the transmitting filter is arranged at a position closest to the common connection terminal, and among all the resonators of the receiving filter, the second series arm resonator in the second series arm resonator section of the receiving filter is arranged at a position closest to the common connection terminal, and the first series arm resonator and the second series arm resonator are connected via the wiring electrode.

[0146] <14> according to <1> ~ <13> The multiplexer described in any one of the preceding claims, wherein the transmission filter is a ladder-type filter having the series arm resonator and the parallel arm resonator, and the reception filter is a ladder-type filter having the series arm resonator and the parallel arm resonator.

[0147] Description of Reference Numerals

[0148] 1A…Transmit filter

[0149] 1B…Receive filter

[0150] 2…Common connection terminal

[0151] 3A, 3B…1st and 2nd signal terminals

[0152] 4…Piezoelectric substrate

[0153] 5…IDT electrode

[0154] 6A, 6B…Reflector

[0155] 7A, 7B…1st and 2nd bus bars

[0156] 8A, 8B...1st and 2nd electrode fingers

[0157] 9…Wiring electrode

[0158] 10…Multiplexer

[0159] 14…Ground terminal

[0160] A…Intersection Area

[0161] B1, B2…tandem arm

[0162] D1, D2…parallel arm

[0163] E1, E2… nodes

[0164] P1~P4, P11~P14…Parallel arm resonator section

[0165] S1~S4, S11~S14…Series arm resonator section

[0166] S4a, S4b, S11a~S11c...series arm resonator.

Claims

1. A multiplexer comprising a transmission filter and a reception filter, wherein each of the transmission filter and the reception filter has a plurality of resonators including at least one series arm resonator, The transmission filter includes a piezoelectric substrate and a first series arm resonator portion formed on the piezoelectric substrate. The receiving filter and the transmitting filter share the piezoelectric substrate and include a second series arm resonator portion formed on the piezoelectric substrate. The transmission filter has an input terminal and an output terminal, and at least one ground terminal. In the circuit structure of the transmission filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, and a connection point between the series arm and the parallel arm is a node. The first series arm resonator unit is one of the series arm resonators or a group of a plurality of series arm resonators connected in series with each other without passing through the node in the transmission filter. The receiving filter has an input terminal and an output terminal, and at least one ground terminal. In the circuit structure of the receiving filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, and a connection point between the series arm and the parallel arm is a node. The second series arm resonator section is one of the series arm resonators or a group of a plurality of series arm resonators connected in series with each other without passing through the node in the reception filter. On the piezoelectric substrate, among all the series arm resonators of the transmission filter, any of the series arm resonators in the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter. On the piezoelectric substrate, among all the resonators of the receiving filter, any of the series arm resonators in the second series arm resonator section is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator section of the transmitting filter, The first series arm resonator unit includes the first series arm resonator having the smallest electrostatic capacitance among all the series arm resonators of the transmitting filter, and the second series arm resonator unit includes the second series arm resonator having the largest electrostatic capacitance among all the series arm resonators of the receiving filter.

2. A multiplexer comprising a transmission filter and a reception filter, wherein the transmission filter and the reception filter each have a plurality of resonators including at least one series arm resonator, The transmission filter includes a piezoelectric substrate and a first series arm resonator portion formed on the piezoelectric substrate. The receiving filter and the transmitting filter share the piezoelectric substrate and include a second series arm resonator portion formed on the piezoelectric substrate. The transmission filter has an input terminal and an output terminal, and at least one ground terminal. In the circuit structure of the transmission filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, and a connection point between the series arm and the parallel arm is a node. The first series arm resonator unit is one of the series arm resonators or a group of a plurality of series arm resonators connected in series with each other without passing through the node in the transmission filter. The receiving filter has an input terminal and an output terminal, and at least one ground terminal. In the circuit structure of the receiving filter, a path connecting the input terminal and the output terminal is a series arm, a path branching from the series arm to the ground terminal is a parallel arm, and a connection point between the series arm and the parallel arm is a node. The second series arm resonator section is one of the series arm resonators or a group of a plurality of series arm resonators connected in series with each other without passing through the node in the reception filter. On the piezoelectric substrate, among all the series arm resonators of the transmission filter, any of the series arm resonators in the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter. On the piezoelectric substrate, among all the resonators of the receiving filter, any of the series arm resonators in the second series arm resonator section is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator section of the transmitting filter, The series arm resonator of each of the transmission filter and the reception filter has an IDT electrode, each of the IDT electrodes includes a plurality of electrode fingers and includes a cross region, and when the direction in which the plurality of electrode fingers extend is set as an electrode finger extension direction, a region in which adjacent electrode fingers overlap each other in a direction perpendicular to the electrode finger extension direction is the cross region, When the dimension of the intersection region along the extension direction of the electrode fingers is set as the intersection width, the first series arm resonator section includes the first series arm resonator whose product of the number of pairs of the plurality of electrode fingers and the intersection width is the smallest among all the series arm resonators of the transmitting filter, and the second series arm resonator section includes the second series arm resonator whose product of the number of pairs of the plurality of electrode fingers and the intersection width is the largest among all the series arm resonators of the receiving filter.

3. The multiplexer according to claim 1 or 2, wherein: The transmission filter and the reception filter share a common connection terminal, and the common connection terminal is the output terminal of the transmission filter and the input terminal of the reception filter.

4. The multiplexer according to any one of claims 1 to 3, wherein: The plurality of resonators of the transmission filter include at least one parallel arm resonator, On the piezoelectric substrate, among all the resonators of the transmission filter, any one of the series arm resonators in the first series arm resonator section is arranged at the shortest distance from all the resonators of the reception filter.

5. The multiplexer according to any one of claims 1 to 4, wherein: The plurality of resonators of the receiving filter include at least one parallel arm resonator, The receiving filter includes a parallel arm resonator portion formed on the piezoelectric substrate. The parallel arm resonator section is one of the parallel arm resonators or a group of a plurality of the parallel arm resonators connected in series with each other in the parallel arm. The parallel arm resonator section including the following parallel arm resonators includes the parallel arm resonator having the largest electrostatic capacitance among all the parallel arm resonators of the receiving filter: on the piezoelectric substrate, among all the parallel arm resonators of the receiving filter, the parallel arm resonator is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator section of the transmitting filter.

6. The multiplexer according to any one of claims 1 to 5, wherein: The center frequency of the passband of the reception filter is higher than the center frequency of the passband of the transmission filter.

7. The multiplexer according to claim 6, wherein: The plurality of resonators of the receiving filter include at least one parallel arm resonator, The receiving filter includes a parallel arm resonator portion formed on the piezoelectric substrate. The parallel arm resonator section is one of the parallel arm resonators or a group of a plurality of the parallel arm resonators connected in series with each other in the parallel arm. The parallel arm resonator section including the following parallel arm resonators includes the parallel arm resonator having the highest resonance frequency among all the parallel arm resonators of the receiving filter: on the piezoelectric substrate, among all the parallel arm resonators of the receiving filter, the parallel arm resonator is arranged at the shortest distance from any of the series arm resonators in the first series arm resonator section of the transmitting filter.

8. The multiplexer according to any one of claims 1 to 7, wherein: The second series arm resonator section of the reception filter includes a plurality of split-type series arm resonators connected in series with one another.

9. The multiplexer according to claim 8, wherein: The number of the series arm resonators in the second series arm resonator section of the reception filter is greater than the number of the series arm resonators in the first series arm resonator section of the transmission filter.

10. The multiplexer according to claim 8 or 9, wherein: The first series arm resonator section of the transmission filter includes a plurality of split-type series arm resonators connected in series with each other. Among the distances between the multiple series arm resonators in the first series arm resonator section and the multiple series arm resonators in the second series arm resonator section, the distance between the first series arm resonator in the first series arm resonator section of the transmitting filter and the second series arm resonator in the second series arm resonator section of the receiving filter is the shortest.

11. The multiplexer according to any one of claims 1 to 9, wherein: The first series arm resonator section of the transmission filter includes a plurality of split-type series arm resonators connected in series with one another.

12. The multiplexer according to any one of claims 1 to 11, wherein: The multiplexer also has: A common connection terminal at which the transmission filter and the reception filter are commonly connected; and a wiring electrode connected to the common connection terminal, Among all the resonators of the transmission filter, any of the series arm resonators in the first series arm resonator section of the transmission filter is arranged at a position closest to the common connection terminal. Among all the resonators of the reception filter, any of the series arm resonators in the second series arm resonator section of the reception filter is arranged at a position closest to the common connection terminal. The series arm resonator disposed at a position closest to the common connection terminal in the transmission filter and the series arm resonator disposed at a position closest to the common connection terminal in the reception filter are connected via the wiring electrode.

13. The multiplexer according to claim 12, wherein: Among all the resonators of the transmission filter, the first series arm resonator in the first series arm resonator section of the transmission filter is arranged at a position closest to the common connection terminal. Among all the resonators of the reception filter, the second series arm resonator in the second series arm resonator section of the reception filter is arranged at a position closest to the common connection terminal. The first series arm resonator and the second series arm resonator are connected via the wiring electrode.

14. The multiplexer according to any one of claims 1 to 13, wherein: The transmission filter is a ladder-type filter including the series-arm resonator and the parallel-arm resonator, and the reception filter is a ladder-type filter including the series-arm resonator and the parallel-arm resonator.

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