JP2014072710A - Duplexer and communication module component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a duplexer that improves an isolation characteristic while maintaining an attenuation characteristic.SOLUTION: In a duplexer 200 having a first piezoelectric substrate 101 with a first acoustic wave filter part 5 on a lower surface, a second piezoelectric substrate 102 with a second acoustic wave filter part on a lower surface, and a circuit substrate 100 with the first piezoelectric substrate 101 and the second piezoelectric substrate 102 mounted on an upper surface, the first acoustic wave filter part 5 has an unbalanced signal pad, a first balanced signal pad and a second balanced signal pad, and the first piezoelectric substrate 101 has, on the lower surface, framing wiring 9 surrounding the first acoustic wave filter part 5 and independently electrically floating.

Description

  The present invention relates to a duplexer and a communication module component.

  A duplexer that demultiplexes a transmission / reception frequency is used in a front end portion of a communication terminal such as a cellular phone.

  The duplexer has an antenna terminal, a transmission terminal, and a reception terminal, a transmission filter is disposed between the antenna terminal and the transmission terminal, and a reception filter is disposed between the antenna terminal and the reception terminal. Has been. In the communication terminal, a transmission circuit and a reception circuit are arranged after the duplexer. The duplexer demultiplexes the transmission signal from the transmission circuit to the antenna terminal and the reception signal received at the antenna terminal to the reception circuit. It has a function to do.

  In such a duplexer, the transmission filter and the reception filter should be matched so that the transmission signal does not flow into the reception circuit or the reception signal does not flow into the transmission circuit. Yes.

  However, depending on the design of each filter, even in the most matched state, for example, when the impedance to the reception filter is slightly lower than the impedance from the transmission filter to the antenna, or the impedance from the antenna to the reception filter The impedance to the transmission filter may be slightly lower. In this case, the isolation characteristic deteriorates due to a signal originally flowing from the transmission filter to the antenna flowing to the reception filter or a signal that should have been input from the antenna to the reception filter flowing to the transmission filter. It will be.

A transmission filter and a reception filter used in a duplexer are often configured by a surface acoustic wave (SAW) filter in which an IDT electrode is formed on a piezoelectric substrate. Isolation characteristics have been improved by adjusting the impedance of each filter by changing the distance between electrode fingers of the IDT electrodes, the number of electrode fingers, or the like (see, for example, Patent Document 1).

  By the way, as a required specification required for the duplexer, an attenuation characteristic (passage characteristic) is important in addition to the isolation characteristic. This is because if either the isolation characteristic or the attenuation characteristic is poor, there arises a problem such as deterioration of the call quality of the mobile phone.

JP-A-5-183380

  However, in the conventional adjustment method, the adjustable range is limited, and it may be difficult to improve the isolation characteristics without deteriorating the attenuation characteristics.

  The present invention has been made to solve the above-described problems, and provides a duplexer capable of improving the isolation characteristic while maintaining the attenuation characteristic, and a communication module component using the duplexer.

  A duplexer according to an aspect of the present invention includes a first piezoelectric substrate having a first acoustic wave filter portion on a lower surface, a second piezoelectric substrate having a second acoustic wave filter portion on a lower surface, and the first piezoelectric substrate on an upper surface. A duplexer including a substrate and a circuit board to which the second piezoelectric substrate is attached, wherein the first acoustic wave filter unit includes an unbalanced signal pad and a balanced signal pad, A lower surface of the substrate is provided with a frame-like wiring that surrounds the first acoustic wave filter portion and is electrically floating independently.

  A communication module component according to an aspect of the present invention includes a module substrate and the duplexer described above.

  According to the above configuration, the isolation characteristic can be improved while maintaining the attenuation characteristic of the duplexer.

1 is an external perspective view of a duplexer according to an embodiment of the present invention. It is an equivalent circuit diagram of the duplexer of the embodiment. It is a top view when the 1st piezoelectric substrate used for the duplexer of an embodiment is seen from the undersurface side. It is a top view when the 2nd piezoelectric substrate used for the duplexer of an embodiment is seen from the undersurface side. It is a top view when the circuit board used for the duplexer of the embodiment is viewed from the upper surface side. 1 is a cross-sectional view taken along line VI-VI of the duplexer. It is a figure which shows the simulation result of the model R for reference, the analysis model A, and the analysis model B, (a) is an isolation characteristic, (b) is a graph which shows a passage characteristic. It is a figure which shows the simulation result of the model R for reference, the analysis model C, and the analysis model D, (a) is an isolation characteristic, (b) is a graph which shows a passage characteristic. It is a figure which shows the simulation result of the model R for a reference, and the analysis model E, and is a graph which shows an isolation characteristic. It is a figure of the module for communication concerning the embodiment of the present invention, (a) is a perspective view and (b) is a block circuit diagram. FIG. 2 is a block circuit diagram of a communication device using the duplexer shown in FIG. 1. FIG. 5 is an external perspective view of a duplexer according to another embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a duplexer according to the present invention will be described in detail with reference to the drawings. In the drawings described below, the same portions are denoted by the same reference numerals. Further, the size of each pattern, the distance between the patterns, the number of vias, the diameter, the shape, and the like are schematically illustrated for explanation, and are not limited thereto.

<Demultiplexer>
A perspective view of a duplexer 200 according to an embodiment of the present invention is shown in FIG. A duplexer 200 shown in FIG. 1 mainly includes a circuit board 100 formed by laminating a plurality of dielectric layers, and a first piezoelectric substrate 101 and a second piezoelectric substrate 102 mounted on the circuit board 100. It is configured. The first piezoelectric substrate 101 and the second piezoelectric substrate 102 are mounted on the upper surface 100 </ b> B of the circuit substrate 100.

  A first acoustic wave filter unit 5 is formed on the surface (lower surface 101A) of the first piezoelectric substrate 101 facing the upper surface 100B of the circuit substrate 100. A second acoustic wave filter unit 6 is formed on the surface (lower surface 102A) of the second piezoelectric substrate 102 facing the upper surface 100B of the circuit board 100.

  The first piezoelectric substrate 101 and the second piezoelectric substrate 102 are entirely covered and protected by a sealing resin 103 (shown by dotted lines).

  Various terminals such as a transmission signal terminal 1, first and second reception signal terminals 2 and 3, an antenna terminal 4, and a reference potential terminal G are formed on the lower surface 100 </ b> A of the circuit board 100.

  The thickness of the circuit board 100 is, for example, 150 μm to 400 μm, and the thicknesses of the first piezoelectric substrate 101 and the second piezoelectric substrate 102 are, for example, 230 μm to 280 μm.

  FIG. 2 is an equivalent circuit diagram of the duplexer 200. The first acoustic wave filter unit 5 is disposed between the antenna terminal 4 and the first and second reception signal terminals 2 and 3 and functions as a reception filter, for example. On the other hand, the 2nd elastic wave filter part 6 is arrange | positioned between the antenna terminal 4 and the transmission signal terminal 1, and functions as a transmission filter, for example.

  The first elastic wave filter unit 5 and the second elastic wave filter unit 6 are set to have different passband frequencies. In the present embodiment, the pass frequency band of the first elastic wave filter unit 5 is set to be higher than the pass frequency band of the second elastic wave filter unit 6. The pass frequency band is 1850 to 1910 MHz, while the pass frequency band of the second elastic wave filter unit 6 is 1930 to 1990 MHz.

  A signal input from the antenna (Ant) to the first elastic wave filter unit 5 is an unbalanced signal, and a signal output from the first elastic wave filter unit 5 is a balanced signal. The first acoustic wave filter unit 5 is mainly composed of two SAW filters 71 and 72 and three SAW resonators 73 to 75. The SAW filters 71 and 72 are double mode SAW filters.

  The signal input from the transmission signal terminal 1 to the second acoustic wave filter unit 6 and the signal output from the second acoustic wave filter unit 6 to the antenna are both unbalanced signals.

  The second elastic wave filter unit 6 is mainly composed of three series resonators 61 to 63 and three parallel resonators 65 to 67. By connecting the series resonators 61 to 63 and the parallel resonators 65 to 67 in a ladder shape, the second acoustic wave filter unit 6 constitutes a ladder type filter. The parallel resonators 65 to 67 of the second elastic wave filter unit 6 are connected to the reference potential terminal G via the reference potential wiring 52. The reference potential wiring 52 has an inductance of a predetermined size, and the inductance and the capacitance of the parallel resonator resonate at a predetermined frequency to form an attenuation pole outside the band. Has increased.

  FIG. 3 is a plan view of the first piezoelectric substrate 101 used in the duplexer according to the present embodiment when viewed from the lower surface 101A side.

The SAW filter 71 is connected to the receiving side input pad 24 via the SAW resonator 73. The receiving side input pad 24 is a pad electrically connected to the antenna terminal 4. On the other hand, the SAW filter 72 is connected to the reception-side first output pad 22 via the SAW resonator 74. The reception-side first output pad 22 is a pad that is electrically connected to the first reception signal terminal 2. The SAW filter 72 is connected to the reception-side second output pad via the SAW resonator 75. The reception-side second output pad is a pad that is electrically connected to the second reception signal terminal 3. The receiving side input pad 24 is an aspect of the “unbalanced signal pad” of the present invention. The reception-side first output pad 22 and the reception-side second output pad 23 are one aspect of the “balanced signal pad” of the present invention.

  The SAW filter 71 and the SAW filter 72 are connected to each other via a signal wiring 81. The SAW filters 71 and 72 are connected to the reference potential pad 25 through the reference potential wiring 82. In the region between the SAW filter 71 and the SAW filter 72, the signal wiring 81 and the reference potential wiring 82 intersect three-dimensionally by sandwiching an insulator between the two wirings. Even in other portions, at portions where wirings having different potentials intersect, a three-dimensional intersection is formed via an insulator.

  A frame-like wiring 9 (hatched for convenience in FIG. 2) is provided on the lower surface 101A of the first piezoelectric substrate 101 so as to surround the entire first acoustic wave filter unit 5. The frame-like wiring 9 is formed in a rectangular shape along the outer periphery of the lower surface 101A of the first piezoelectric substrate 101, for example. The shape of the frame-shaped wiring 9 is not limited to this, and may be any shape as long as it covers the entire first acoustic wave filter unit 5. For example, the corners as shown in FIG. 3 may not be rectangular at right angles, but may be rectangular with outwardly convex curved surfaces, or each side is not linear but other pads, etc. It may be curved as well.

  The frame-like wiring 9 is not electrically connected to any of the filters, resonators, wirings, and pads constituting the first acoustic wave filter unit 5, and is electrically connected to the circuit board 100 side. There is no connection. That is, the frame-like wiring 9 is in an electrically floating state independently. In this way, the frame-like wiring 9 is not electrically connected to other wirings, and when mounted on the circuit board 100, solder or the like is not applied here, so that the width thereof is made relatively narrow. For example, the width is 10 μm to 30 μm.

  By providing such a frame-like wiring 9, the isolation characteristic of the duplexer 200 can be improved as will be described later.

  FIG. 4 is a plan view of the second piezoelectric substrate 102 used in the duplexer 200 according to the present embodiment when viewed from the lower surface 102A side.

  As shown in FIG. 4, the series resonators 61, 62, and 63 and the parallel resonators 65, 66, and 67 that constitute the second elastic wave filter unit 6 are each composed of a SAW resonator. Of these, the series resonators 61, 62, 63 and the parallel resonators 65, 66 are series-divided resonators.

  A series resonator 61 arranged at one end of the series resonator is connected to the transmission-side output pad 34. The transmission side output pad 34 is a pad electrically connected to the antenna terminal 4. A series resonator 63 disposed at the other end of the series resonators is connected to the transmission-side input pad 31. The transmission side output pad 31 is a pad electrically connected to the transmission signal terminal 1. Each parallel resonator 65, 66, 67 is connected to the transmission-side reference potential pad 35. The transmission-side reference potential pad 35 is a pad that is electrically connected to the reference potential terminal G.

  FIG. 5 is a plan view of the upper surface 100 </ b> B of the circuit board 100. In FIG. 5, the first piezoelectric substrate 101 is mounted in the left region, and the second piezoelectric substrate 102 is mounted in the right region. The mounting area of the second piezoelectric substrate 102 is indicated by a dotted line for convenience.

A conductor pattern group is formed on the upper surface 100 </ b> B of the circuit board 100. Specifically, in the mounting area of the first piezoelectric substrate 101, the reception-side first conductor pattern 22 ′, the reception-side second conductor pattern 23 ′, the reception-side third conductor pattern 24 ′, and the reception-side fourth conductor pattern 25. A first conductor pattern group including 'is formed. On the other hand, a second conductor pattern group including a transmission side first conductor pattern 31 ′, a transmission side second conductor pattern 34 ′, and a transmission side third conductor pattern 35 ′ is formed in the mounting region of the second piezoelectric substrate 102. Yes.

  Each of these conductor patterns is formed at a position corresponding to each pad provided on the first piezoelectric substrate 101 and the second piezoelectric substrate 102 when the first piezoelectric substrate 101 and the second piezoelectric substrate 102 are mounted on the circuit substrate 100. These pads are connected to these pads by a conductive bonding material such as solder.

  Specifically, the receiving side first conductor pattern 22 ′, the receiving side second conductor pattern 23 ′, the receiving side third conductor pattern 24 ′, and the receiving side fourth conductor pattern 25 ′ are the receiving side first output pad 22, the receiving side. The second output pad 23, the receiving side input pad 24, and the receiving side reference potential pad 25 are connected to each other. The transmission side first conductor pattern 31 ′, the transmission side second conductor pattern 34 ′, and the transmission side third conductor pattern 35 ′ are connected to the transmission side output pad 31, the transmission side input pad 34, and the transmission side third output pad 35, respectively. Has been.

  These conductor patterns are connected to the pads of the first piezoelectric substrate 101 and the second piezoelectric substrate 102, and are also connected to the terminals provided on the lower surface 100A of the circuit board 100.

  Specifically, the reception side first conductor pattern 22 ′ is connected to the first reception signal terminal 2, the reception side second conductor pattern 23 ′ is connected to the second reception signal terminal 3, and the reception side third conductor pattern 24 ′. Is connected to the antenna terminal 4, and the receiving-side fourth conductor pattern 25 ′ is connected to the reference potential terminal G. The transmission side first conductor pattern 31 ′ is connected to the transmission signal terminal 1, the transmission side second conductor pattern 34 ′ is connected to the antenna terminal 4, and the transmission side third conductor pattern 35 ′ is connected to the reference potential terminal G. Has been.

  In the mounting area of the first piezoelectric substrate 101 on the upper surface 100B of the circuit board 100, a first conductor pattern group (receiving side first conductor pattern 22 ′, receiving side second conductor pattern 23 ′, receiving side third conductor pattern 24 ′). And a frame-like conductor pattern 11 surrounding the receiving-side fourth conductor pattern 25 ′). The frame-like conductor pattern 11 surrounds the first conductor pattern group, but the second conductor pattern group (transmission side first conductor pattern 31 ′, transmission side second conductor pattern 34 ′ and transmission side third conductor pattern 35 ′. ) Is not enclosed. That is, the frame-shaped conductor pattern 11 surrounds only the first conductor pattern group.

  This frame-like conductor pattern 11 is not connected to any conductor pattern, and is not connected to any of the pads of the first piezoelectric substrate 101 and the second piezoelectric substrate 102 and the frame-like wiring 9. That is, the frame-like conductor pattern 11 is in an electrically floating state independently.

  By forming such a frame-shaped conductor pattern 11, the isolation characteristic of the duplexer 200 can be further improved.

  The frame-shaped conductor pattern 11 is formed in a rectangular shape, for example, and is arranged at a position overlapping the frame-shaped wiring 9 in a state where the first piezoelectric substrate 101 is mounted on the circuit board 100. However, as described above, the frame-shaped conductor pattern 11 and the frame-shaped wiring 9 are not connected. The shape of the frame-like conductor pattern 11 may be any shape as long as it surrounds the first conductor pattern group. For example, the corners may be rounded instead of right-angled as shown in FIG. The straight side may be curved. Moreover, the width | variety of the frame-shaped conductor pattern 11 is 10 micrometers-40 micrometers, for example.

  FIG. 6 is a cross-sectional view of the duplexer 200, which corresponds to a cross section taken along line VI-VI in FIG.

  As shown in FIG. 6, the circuit board 100 has a two-layer structure. Each layer is made of a dielectric material or the like. As a dielectric material constituting the circuit board 100, for example, ceramics mainly composed of alumina, glass ceramics that can be sintered at a low temperature, glass epoxy resins mainly composed of organic materials, and the like are used. In the case of using ceramics or glass ceramics, a green sheet was produced by molding a slurry in which a metal oxide such as ceramics and an organic binder were homogeneously kneaded with an organic solvent into a sheet, and a desired conductor pattern or via was formed. Thereafter, these green sheets are laminated and pressure-bonded to form an integrated body, and then fired. The circuit board 100 is not limited to a two-layer structure, and may be three or more layers or may be a single layer.

  A via conductor 7 and an internal conductor pattern 8 are formed inside the circuit board 100. A conductor pattern group provided on the upper surface 100B of the circuit board 100 is connected to each terminal provided on the lower surface 100A through the via conductor 7 and the internal conductor pattern 8. In order to obtain a predetermined inductance, an inner conductor pattern 8 having a spiral or meandering portion may be provided.

  The surface layer conductor pattern group, the inner conductor pattern 8 and the via conductor 7 are made of a conductor material such as aluminum, silver, an alloy obtained by adding palladium to silver, tungsten, copper, and gold. The conductor pattern group and the inner conductor pattern 8 are formed by, for example, forming a conductor material by a method such as a vapor deposition method or a sputtering method and then patterning the conductor film by an etching method or the like. In addition, it can be formed by a screen printing method or the like. The via conductor 7 can also be formed by, for example, a screen printing method. Each conductor pattern constituting the conductor pattern group may be plated with Ni or Au on the surface thereof.

  Connection between the conductor pattern group and each pad of the first circuit board 101 and the second circuit board 102 is performed via a conductive bonding material 10 such as solder. As a result, the first circuit board 101, the second circuit board 102, and the circuit board 100 are electrically and mechanically connected.

  The first circuit board 101 and the second circuit board 102 mounted on the circuit board 100 are entirely covered with a sealing resin 103. The sealing resin 103 is made of a resin material such as an epoxy resin or a polyimide resin. The sealing resin 103 enters the portion where the first acoustic wave filter portion 5 is formed on the lower surface of the first piezoelectric substrate 101 and the portion where the second acoustic wave filter portion 6 is formed on the lower surface of the second piezoelectric substrate 102. The viscosity is adjusted or a predetermined production method is adopted so that there is no such problem.

  Next, the result of considering the influence of the frame-shaped wiring 9 and the frame-shaped conductor pattern 11 on the electrical characteristics will be described with reference to FIGS. Specifically, in the duplexer 200 described above, a reference model R that does not form the frame-like wiring 9 and the frame-like conductor pattern 11 is referred to as the reference model R, and the frame-like wiring 9 and the frame-like wiring. The conductor pattern 11 was considered by comparing the electrical characteristics with the analysis models A to E having different modes. In addition, all the electrical characteristics were calculated | required by calculation by simulation. The pass frequency band of the duplexer is 1930 to 1990 MHz on the reception side (first elastic wave filter unit 5), and 1850 to 1910 MHz on the transmission side (second elastic wave filter unit 6).

FIG. 7 shows a comparison result between the analysis model A and the analysis model B with the reference model R. FIG. 7A is a graph showing isolation characteristics, and FIG. 7B is a graph showing pass characteristics. In FIG. 7, the normal normal line is the reference model R, the broken line is the analysis model A, and the dashed line is the calculation result of the analysis model B.

  The analysis model A is a duplexer in which the frame-shaped wiring 9 is formed on the first piezoelectric substrate 101 and the frame-shaped conductor pattern 11 is not formed on the circuit substrate 100. This corresponds to the duplexer 200 in which the frame-shaped conductor pattern 11 is omitted.

  The analysis model B is a duplexer in which the frame-shaped conductor pattern 11 is formed on the circuit board 100 and the frame-shaped wiring 9 is not formed on the first piezoelectric substrate 101. This corresponds to the duplexer 200 in which the frame-like wiring 9 is omitted.

  From the results shown in FIG. 7A, it was confirmed that both the analysis model A and the analysis model B have improved isolation characteristics in the pass frequency band on the transmission side as compared with the reference model R. In particular, the analysis model A showed a significant improvement effect compared to the analysis model B. Specifically, the improvement amount of the analysis model B is 1 dB, while the improvement amount of the analysis model A is 6 dB.

  On the other hand, as shown in FIG. 7 (b), neither the analysis model A nor the analysis model B was deteriorated in pass characteristics as compared with the reference model R.

  FIG. 8 shows a comparison result between the analysis model C and the analysis model D with the reference model R. FIG. 8A is a graph showing isolation characteristics, and FIG. 8B is a graph showing pass characteristics. In FIG. 8, the normal line is the calculation result of the reference model R, the dotted line is the analysis model C, and the thick dashed line is the calculation result of the analysis model D.

  The analysis model C is a duplexer in which the frame-shaped wiring 9 is formed on the first piezoelectric substrate 101 and the frame-shaped conductor pattern 11 is formed on the circuit substrate 100. This corresponds to the duplexer 200.

  In the analysis model D, the frame-shaped wiring 9 is formed on the first piezoelectric substrate 101, the frame-shaped conductor pattern 11 is formed on the circuit board 100, and the frame-shaped wiring 9 and the frame-shaped conductor pattern 11 are electrically connected. It is a vessel.

  From the results shown in FIG. 8A, it was confirmed that both the analysis model C and the analysis model D have improved isolation characteristics in the pass frequency band on the transmission side compared to the reference model R. In particular, the analysis model C showed a significant improvement effect compared to the analysis model D. Specifically, the improvement amount of the analysis model D is 2.5 dB, while the improvement amount of the analysis model C is 7 dB.

  On the other hand, as shown in FIG. 8 (b), neither the analysis model C nor the analysis model D showed any deterioration in the pass characteristics as compared with the reference model R.

  FIG. 9 is a graph showing a comparison result of the isolation characteristics of the analysis model E with the reference model R. In FIG. 9, the normal normal line is the calculation result of the reference model R, and the thick broken line is the calculation result of the analysis model E.

  The analysis model E is a duplexer in which a frame-like wiring surrounding the second elastic wave filter unit 6 is formed on the second piezoelectric substrate 102 and the frame-shaped conductor pattern 11 is not formed on the circuit substrate 100.

From the results shown in FIG. 9, it is confirmed that although the isolation characteristic in the transmission frequency band on the transmission side is slightly improved in the analysis model E compared to the reference model R, the isolation characteristic in the transmission frequency band on the reception side is greatly deteriorated. did it.

  From the above results, it was confirmed that if the frame-like wiring 9 surrounding only the first acoustic wave filter unit 5 functioning at least as a reception filter is formed, the isolation characteristics can be improved while maintaining the pass characteristics. Furthermore, in addition to the frame-shaped wiring 9, by forming a frame-shaped conductor pattern 11 that surrounds only the first conductor pattern group of the circuit board 100 electrically connected to the first acoustic wave filter unit 5, the isolation characteristics can be obtained. It was confirmed that it improved further.

  The reason why the isolation characteristics can be improved by providing the frame-like wiring 9 in an electrically floating state is not necessarily clear, but one reason is considered as follows.

  First, the balanced signal pads 22 and 23 are provided in the first filter unit 5. By forming the frame-shaped wiring 9 so as to surround the first filter unit 5, the frame-shaped wiring 9 and the balanced signal pad 22 are formed. , 23 to form a capacitance. A part of the signal passing through the first filter unit 5 leaks into the frame-shaped wiring 9 through this capacitance. On the other hand, even if the first filter unit 5 and the second filter unit 6 are formed on separate piezoelectric substrates, the isolation characteristic is that the signal of the second filter unit 6 is transmitted through the space. It gets worse by leaking into part 5. At this time, the signal leaking from the second filter unit 6 to the first filter unit 5 through the space acts so as to cancel out the signal propagating from the balanced signal pads 22 and 23 through the frame-like wiring 9 through the capacitance. It is considered that the isolation characteristics are improved.

<Communication module parts>
Next, an embodiment of the communication module component of the present invention will be described. FIG. 10 is a perspective view of the communication module component 400 according to the present embodiment. The communication module component 400 includes, in addition to the duplexer 200, a power amplifier PA, a bandpass filter BPF, and the like, and is used as a transmission module such as a mobile phone.

  The communication module component 400 is obtained by mounting the duplexer 200, the power amplifier PA, and the band pass filter BPF on the upper surface of the module substrate 300 and coating these components with a resin 301. The communication module of the present embodiment is excellent in electrical characteristics by mounting the duplexer 200 described above.

<Communication device>
Next, an embodiment of a communication apparatus using the above-described duplexer 200 will be described. FIG. 11 is a block diagram of the communication apparatus according to the present embodiment. 11 includes an antenna ANT, an RF circuit 600 connected to the antenna ANT, an IF circuit 700 connected to the RF circuit 600, a signal processing circuit DSP connected to the IF circuit, and a signal processing circuit. And an interface unit 800 connected to the DSP.

  The RF circuit 600 includes a duplexer 200, a power amplifier PA, a transmission bandpass filter BPF1, a low noise amplifier LNA, a reception bandpass filter BPF2, and a local oscillator LO. The IF circuit 700 includes a modulator MOD, a low-pass filter LPS, and a demodulator De-MOD. The interface unit 800 includes a control unit CONT, an operation unit KB, a microphone MIC, and a speaker SP.

As shown in the figure, the audio signal input from the microphone MIC is A / D converted by a DSP (Digital Signal Processor), then modulated by the modulator MOD, and further, the frequency is output by the mixer using the oscillation signal of the local oscillator LO. Converted. The output of the mixer passes through the transmission bandpass filter BPF1 and the power amplifier PA, passes through the duplexer 200, and passes through the antenna ANT.
Is output. A reception signal from the antenna ANT passes through the duplexer 200, and is input to the mixer through the low noise amplifier LNA and the reception band pass filter BPF2. The mixer converts the frequency of the received signal using the oscillation signal of the local oscillator LO, and the converted signal is demodulated by the demodulator De-MOD through the low-pass filter LPF and further D / A converted by the DSP, and the speaker. An audio signal is output from. Since the communication apparatus shown in FIG. 11 includes the duplexer 200, the communication quality is excellent.

  FIG. 12 is a perspective view of a duplexer 201 according to another embodiment of the present invention. In the duplexer 200 in the above-described embodiment, the first acoustic wave filter unit 5 and the second acoustic wave filter unit 6 are formed on separate piezoelectric substrates. However, in the duplexer 201, the first acoustic wave filter unit is formed. 5 and the second elastic wave filter unit 6 are formed on the same piezoelectric substrate 104. The configuration other than the piezoelectric substrate 104 is the same as that of the duplexer 200.

  Even when the first acoustic wave filter unit 5 and the second acoustic wave filter unit 6 are formed on the same piezoelectric substrate 104 as in the duplexer 201, the isolation characteristics can be improved by providing the frame-shaped wiring 9. it can.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  For example, in the above-described embodiment, the duplexer in which the pass frequency band of the first elastic wave filter unit 5 is higher than the pass frequency band of the second elastic wave filter unit 6 has been described. The present invention can also be applied to a duplexer whose frequency band is higher than the pass frequency band of the first elastic wave filter unit 5.

  Alternatively, only the frame-like wiring 9 may be provided on the first piezoelectric substrate 101 without providing the frame-like conductor pattern 11 provided on the circuit board 100.

  In the above-described embodiment, the duplexer in which the second filter unit 6 is configured by a ladder filter has been described. However, the second filter unit 6 is not limited to this, and for example, a piezoelectric thin film resonator (FBAR: Film). A filter configured by a Bulk Acoustic Resonator may be used.

DESCRIPTION OF SYMBOLS 1 ... Transmission signal terminal 2 ... 1st reception signal terminal 3 ... 2nd reception signal terminal 4 ... Antenna terminal 5 ... 1st elastic wave filter part 6 ... 2nd elastic wave filter Part 7: Via conductor 8 ... Internal conductor pattern 9 ... Frame-like wiring 10 ... Conductive bonding material 11 ... Frame-like conductor pattern 100 ... Circuit board 101 ... First piezoelectric Substrate 102 ... Second piezoelectric substrate

Claims (5)

A first piezoelectric substrate having a first acoustic wave filter portion on the bottom surface, a second piezoelectric substrate having a second acoustic wave filter portion on the bottom surface, and a circuit having the first piezoelectric substrate and the second piezoelectric substrate attached to the top surface A duplexer comprising a substrate,
The first acoustic wave filter unit has an unbalanced signal pad and a balanced signal pad,
A duplexer provided on the lower surface of the first piezoelectric substrate with a frame-like wiring that surrounds the first acoustic wave filter section and is electrically floating independently.   On the upper surface of the circuit board, a first conductor pattern group electrically connected to the first acoustic wave filter portion, a second conductor pattern group electrically connected to the second acoustic wave filter portion, 2. The duplexer according to claim 1, wherein a frame-like conductor pattern that surrounds only the first conductor pattern group and is electrically floating independently is provided.   3. The duplexer according to claim 1, wherein the second acoustic wave filter unit includes a plurality of series resonators and a plurality of parallel resonators connected in a ladder shape. A duplexer comprising: a piezoelectric substrate having a first acoustic wave filter portion and a second acoustic wave filter portion on a lower surface; and a circuit substrate having the piezoelectric substrate attached to the upper surface,
The first acoustic wave filter unit has an unbalanced signal pad, a first balanced signal pad, and a second balanced signal pad,
A duplexer having a lower surface of the piezoelectric substrate provided with a frame-like wiring that surrounds only the first acoustic wave filter portion and is electrically floating independently. A module board;
A communication module component comprising the duplexer according to claim 1 mounted on the module substrate.

Images