JP6822299B2 - High frequency front end circuits and communication equipment - Google Patents

Description

The present invention relates to high frequency front end circuits and communication devices.

In recent years, mobile phones are required to support a plurality of frequencies and wireless systems with one terminal (multi-band and multi-mode). Front-end modules that support multi-band and multi-mode are required to process a plurality of transmitted / received signals at high speed without degrading the quality. In particular, carrier aggregation is required to simultaneously transmit and receive high-frequency signals of a plurality of bands.

Patent Document 1 discloses an RF system including an LB (low band) diversity antenna, an MB (middle band) / HB (high band) diversity antenna, and a diversity module (see FIG. 6 of Patent Document 1). The diversity module includes a unipolar multi-throw switch connected to the MB / HB diversity antenna, a plurality of filters connected to the unipolar multi-throw switch, and an amplifier circuit connected to the plurality of filters. doing. Each of the plurality of filters has each band as a pass band. According to this configuration, carrier aggregation (CA) operation in which high frequency signals of a plurality of bands are simultaneously used for communication is possible.

JP-A-2015-208007

In the RF system described in Patent Document 1, when two or more filters are operated by CA, it is necessary to open the pass band of the other filter in one filter. As a result, even in the case of CA operation, one filter can propagate a high frequency signal with low loss without being affected by the impedance of the other filter.

However, when the number of combinations of bands operated by CA increases and there are a plurality of such combinations, it becomes necessary to adjust the impedance of each filter for each combination of bands, which complicates the design of each filter and optimizes the filter characteristics of all filters. It becomes difficult to change. Further, as the number of combinations of bands operated by CA increases, the number of selection terminals of the single-pole multi-throw switch increases, so that the single-pole multi-throw switch becomes large.

Therefore, the present invention has been made to solve the above problems, and provides a small high-frequency front-end circuit and communication device capable of maintaining low-loss signal propagation characteristics even during CA operation. The purpose.

In order to achieve the above object, the high frequency front end circuit according to one aspect of the present invention includes an antenna common terminal connected to an antenna element, a first input / output terminal and a second input / output terminal, and a first terminal and a first terminal. A first filter having two terminals, having a first pass band, and the first terminal being connected to the antenna common terminal, and the antenna common terminal and the second input / output being connected to the antenna common terminal. A switch having a second filter arranged between terminals and having a second pass band different from the first pass band, a common terminal, and a plurality of selection terminals, the common terminal being connected to the second terminal. And a third filter connected to the first selection terminal among the plurality of selection terminals and arranged between the switch and the first input / output terminal, and the first filter is used alone. The reflection coefficient in the second pass band when viewed from the antenna common terminal side is larger than the reflection coefficient in the second pass band when the third filter is viewed alone from the antenna common terminal side.

When the first filter and the second filter constituting the demultiplexing / combining circuit are connected in common at the common antenna terminal, the insertion loss in the second pass band of the second filter is that of the second filter alone. In addition to the insertion loss, it is affected by the reflection characteristics seen from the antenna common terminal side of the first filter. More specifically, the insertion loss in the second pass band of the second filter decreases as the reflection coefficient in the second pass band seen from the common terminal side of the first filter increases.

According to the above configuration, the reflection coefficient in the second pass band of the first filter is larger than the reflection coefficient in the second pass band of the third filter. Here, since the third filter arranged after the first filter places more importance on the filter passing characteristic and the attenuation characteristic than the reflection characteristic, it is possible to realize good passing characteristics of the first filter and the third filter. .. That is, without arranging a switch between the antenna element and the first filter and the second filter, the insertion loss in the second pass band of the second filter can be applied to the first filter, the third filter, or both. Since the resulting insertion loss can be effectively reduced, it is possible to provide a small high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation.

Further, each of the first filter and the third filter includes two or more elastic wave resonators, and is arranged on the antenna common terminal side of the two or more elastic wave resonators constituting the first filter. When one or more elastic wave resonators are viewed alone from the antenna common terminal side, the reflectance coefficient in the second passing band is the antenna among the two or more elastic wave resonators constituting the third filter. One or more elastic wave resonators arranged on the common terminal side may be larger than the reflectance coefficient in the second passage band when viewed from the antenna common terminal side alone.

In a filter composed of a plurality of elastic wave resonators, the reflectance coefficient seen from the common terminal side is dominated by the reflection coefficient of one elastic wave resonator closest to the common terminal. According to this, among the insertion losses in the second pass band of the second filter, the insertion loss caused by the first filter, the third filter, or both can be effectively reduced.

Further, at least one of the first filter and the third filter has a ladder type filter structure, and one or more elastic wave resonators arranged on the antenna common terminal side are a series arm resonator and a parallel arm. It may contain at least one of the resonators.

As a result, the insertion loss due to the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter is ensured while ensuring the low loss of the first filter and the third filter. Can be reduced.

Further, at least one of the first filter and the third filter may have a vertically coupled filter structure.

This makes it possible to adapt the first filter and the third filter to the filter characteristics that require attenuation enhancement and the like.

Further, the second input / output terminal is connected to the second amplifier circuit, and the filter circuit may not be arranged between the second filter and the second amplifier circuit.

In the subsequent stage of the second filter, a plurality of filters corresponding to a plurality of bands included in the second pass band and narrower than the second pass band are usually arranged. However, no further filter circuit may be arranged on the signal path of the band that does not require a filter characteristic higher than the filter characteristic of the second filter, that is, between the second filter and the second amplifier circuit. This makes it possible to further reduce the size of the high frequency front end circuit.

Further, a third input / output terminal, a fourth filter connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band are further provided. The first filter, the second filter, and the fourth filter constitute a triplexer, and the first pass band, the second pass band, and the third pass band are low bands (LB: 698-960 MHz). , Middle band (MBa: 1710-2200 MHz), high band (HBa: 2300-2690 MHz), the first pass band may be any of the low band, the middle band, and the high band. ..

As a result, the first filter and the second filter are applied to LB, MBa, and HBa-compatible triplexers. Therefore, in a configuration including a triplexer compatible with LB, MBa, and HBa, it is possible to realize a small high-frequency front-end circuit that can maintain low-loss signal propagation characteristics even during CA operation.

Further, a fourth filter connected to the third input / output terminal and the fourth input / output terminal and the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band. And a fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band, the first filter, the first filter, and the like. The two filters, the fourth filter, and the fifth filter constitute a quad plexer, and the first pass band, the second pass band, the third pass band, and the fourth pass band are low bands (LB). : 698-960 MHz), middle band (MBa: 1710-2200 MHz), middle high band (MHBa: 2300-2400 MHz), high band (HBb: 2496-2690 MHz), and the first pass band is the low band, said It may be either a middle band, the middle high band, or the high band.

Thereby, the first filter and the second filter are applied to the quad plexa corresponding to LB, MBa, MHBa and HBa. Therefore, in a configuration including a quad regulator compatible with LB, MBa, MHBa, and HBa, it is possible to realize a compact high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation.

Further, a fourth filter connected to the third input / output terminal and the fourth input / output terminal and the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band. And a fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band, the first filter, the first filter, and the like. The two filters, the fourth filter, and the fifth filter constitute a quad plexer, and the first pass band, the second pass band, the third pass band, and the fourth pass band are middle low bands ( It is applied to MLB: 1475.9-2025 MHz), middle band (MBb: 2110-2200 MHz), middle high band (MHBa: 2300-2400 MHz or MHBb: 2300-2370 MHz), high band (HBb: 2496-2690 MHz). The 1 pass band may be any one of the middle low band, the middle band, the middle high band, and the high band.

Thereby, the first filter and the second filter are applied to the quad plexa corresponding to MLB, MBb, MHBa and HBb. Therefore, in a configuration including a quad regulator compatible with MLB, MB, MHB, and HB, it is possible to realize a small high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation.

Further, a fourth filter connected to the third input / output terminal and the fourth input / output terminal and the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band. And a fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band, the first filter, the first filter, and the like. The two filters, the fourth filter, and the fifth filter constitute a quad plexer, and the first pass band, the second pass band, the third pass band, and the fourth pass band are middle low bands ( It is applied to MLB: 1475.9-2025 MHz), middle band (MBb: 2110-2200 MHz), middle high band (MHBa: 2300-2400 MHz or MHBb: 2300-2370 MHz), high band (HBb: 2496-2690 MHz). The 1 pass band is any of the middle low band, the middle band, and the high band, and the second pass band is the middle high band, which connects the second filter and the second amplification circuit. The filter circuit may not be arranged on the signal path.

Thereby, the first filter and the second filter are applied to the quad plexa corresponding to MLB, MBb, MHBa and HBb. Further, if the passing characteristic of the band included in the MHBa is sufficient as the passing characteristic of the second filter, the filter circuit may not be arranged on the signal path of the band. Therefore, in a configuration including a quad regulator compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation can be realized.

Further, the signal path connecting the second filter and the second amplifier circuit may be a path for transmitting and receiving Band 40a (reception band: 2300-2370 MHz).

As a result, the pass characteristic of the Band 40a contained in the MHBa is sufficient for the pass characteristic of the second filter, so that the filter circuit does not have to be arranged on the signal path of the Band 40a. Therefore, in a configuration including a quad regulator compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation can be realized.

Further, the signal path connecting the second filter and the second amplifier circuit may be a path for transmitting and receiving Band 40 (reception band: 2300-2400 MHz).

As a result, the pass characteristic of the Band 40 included in the MHBa is sufficient for the pass characteristic of the second filter, so that the filter circuit does not have to be arranged on the signal path of the Band 40. Therefore, in a configuration including a quad regulator compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation can be realized.

Further, a third input / output terminal and a fourth input / output terminal are connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and have a third pass band. The first filter includes a fourth filter, a fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band. The second filter, the fourth filter, and the fifth filter constitute a quad plexer, and the first pass band, the second pass band, the third pass band, and the fourth pass band are middle low bands. (MLB: 1475.9-2025 MHz), middle band (MBb: 2110-2200 MHz), middle high band (MHBa: 2300-2400 MHz or MHBb: 2300-2370 MHz), high band (HBb: 2496-2690 MHz). The first pass band is any of the middle low band, the middle band, and the middle high band, and the second pass band is the high band, which connects the second filter and the second amplification circuit. The filter circuit may not be arranged on the signal path.

Thereby, the first filter and the second filter are applied to the quad plexa corresponding to MLB, MBb, MHBa and HBb. Further, if the passing characteristic of the band included in the HBb is sufficient as the passing characteristic of the second filter, the filter circuit may not be arranged on the signal path of the band. Therefore, in a configuration including a quad regulator compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation can be realized.

Further, the signal path connecting the second filter and the second amplifier circuit may be a path for transmitting and receiving Band 41 (reception band: 2496-2690 MHz).

As a result, the pass characteristic of the Band 41 included in the HBb is sufficient for the pass characteristic of the second filter, so that the filter circuit does not have to be arranged on the signal path of the Band 41. Therefore, in a configuration including a quad regulator compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of maintaining low-loss signal propagation characteristics even during CA operation can be realized.

Further, the first pass band is located on the higher frequency side than the second pass band, and each of the first filter and the third filter contains one or more surface acoustic wave resonators to form the first filter. Each of the above-mentioned one or more surface acoustic wave resonators is a surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate, and in the first filter, (1). ) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ , (2) leaky waves propagating in the piezoelectric layer made of LiTaO ₃ , and (3) love waves propagating in the piezoelectric layer made of LiNbO ₃ . Any of the above may be used as a surface acoustic wave.

Reflection loss at low frequencies than the resonance point and the antiresonance point of the acoustic wave resonator, leaky waves, and LiNbO ₃ propagating Rayleigh wave propagating piezoelectric layer made of LiNbO _3, a piezoelectric layer made of LiTaO ₃ When any one of the Rayleigh waves propagating in the piezoelectric layer composed of the above is used as an elastic surface wave, it is smaller than when another elastic wave is used.

Therefore, when the first filter is the high frequency side filter and the second filter is the low frequency side filter, the reflectance coefficient in the second pass band of the first filter is calculated from the reflectance coefficient in the second pass band of the third filter. Can also be increased. This makes it possible to reduce the insertion loss caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter.

Further, in the third filter, the elastic wave resonator may be composed of SMR (Solidly Mountain Resonator) or FBAR (Film Bulk Acoustic Resonator).

According to this, it is possible to secure low loss property and steepness of the pass band of the third filter while increasing the reflection coefficient of the first filter.

Further, the first pass band is located on the higher frequency side than the second pass band, and each of the first filter and the third filter contains one or more elastic wave resonators to form the first filter. Each of the one or more elastic wave resonators is an elastic surface wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. In the first filter, elastic waves are formed. The resonator is the piezoelectric layer in which the IDT electrode is formed on one of the main surfaces, a high-sound velocity support substrate in which the bulk wave sound velocity propagating is faster than the elastic wave sound velocity propagating in the piezoelectric layer, and the above. It has a sound velocity film laminated structure composed of a low sound velocity film which is arranged between the high sound velocity support substrate and the piezoelectric layer and has a bulk wave sound velocity which propagates slower than the elastic wave sound velocity propagating in the piezoelectric layer. In the third filter, the elastic wave resonator may be composed of SMR or FBAR.

The reflectance coefficient in the low frequency region is larger in the low frequency region than in the resonance point and the antiresonance point of the elastic wave resonator in the case of having the sound velocity film laminated structure than in the case where the elastic wave resonator is composed of SMR or FBAR.

Therefore, when the first filter is the high frequency side filter and the second filter is the low frequency side filter, the reflectance coefficient in the second pass band of the first filter is calculated from the reflectance coefficient in the second pass band of the third filter. Can also be increased. This makes it possible to reduce the insertion loss caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Further, the low loss property of the third filter and the steepness of the pass band can be ensured while increasing the reflection coefficient of the first filter.

Further, the first pass band is located on the lower frequency side than the second pass band, and each of the first filter and the third filter contains one or more elastic wave resonators, and the first filter includes one or more elastic wave resonators. , (1) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ are used as elastic surface waves, (2) elastic wave resonators are composed of SMRs, and (3) elastic wave resonators are composed of FBARs. It may be either.

In the region higher than the resonance point and anti-resonance point of the elastic wave resonator, an unnecessary wave is generated due to bulk wave leakage, and the unnecessary wave intensity is determined by using a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ as an elastic surface wave. It can be made the smallest in any of the cases of utilizing, the elastic wave resonator is composed of SMR, and the elastic wave resonator is composed of FBAR.

Therefore, when the first filter is the low frequency side filter and the second filter is the high frequency side filter, the reflectance coefficient in the second pass band of the first filter is calculated from the reflectance coefficient in the second pass band of the third filter. Can also be increased. This makes it possible to reduce the insertion loss caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter.

Further, in the third filter, (1) the elastic wave resonator propagates more than the piezoelectric layer in which the IDT electrode is formed on one main surface and the elastic wave sound velocity propagating in the piezoelectric layer. Is a high-speed treble support substrate, and a low-velocity film that is arranged between the treble support substrate and the piezoelectric layer and has a bulk wave sound velocity that is slower than the surface acoustic wave propagating through the piezoelectric layer. (2) A leaky wave propagating in a piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, and (3) a love wave propagating in a piezoelectric layer made of LiNbO ₃ , which has a sound velocity film laminated structure composed of May be used as a surface acoustic wave.

According to this, when the third filter has a sound velocity film laminated structure while increasing the reflectance coefficient of the first filter, low loss property and good temperature characteristics of the third filter can be ensured, and the third filter can be secured. When the love wave generated by LiNbO ₃ is used as a surface acoustic wave in the filter, a wide bandwidth of the third filter can be secured.

Further, the first pass band is located on the lower frequency side than the second pass band, and each of the first filter and the third filter contains one or more surface acoustic wave resonators, and the first filter and the first filter Each of the surface acoustic wave resonators constituting the third filter is a surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. The surface acoustic wave resonator is a piezoelectric layer in which the IDT electrode is formed on one of the main surfaces, and a high-pitched sound velocity support substrate in which the bulk wave sound velocity propagating is higher than the surface acoustic wave velocity propagating in the piezoelectric layer. And a sound velocity film laminated structure composed of a low sound velocity film which is arranged between the high sound velocity support substrate and the piezoelectric layer and whose bulk wave sound velocity propagating is lower than the surface acoustic wave sound velocity propagating in the piezoelectric layer. The third filter uses (1) a surface acoustic wave propagating in the piezoelectric layer made of LiTaO ₃ as a surface acoustic wave, or (2) a love wave propagating in the piezoelectric layer made of LiNbO _3. May be used as a surface acoustic wave.

In the high frequency region than the resonance point and anti-resonance point of the surface acoustic wave resonator, an unnecessary wave is generated due to bulk wave leakage, and the unnecessary wave intensity is the leaky wave of LiTaO ₃ when the sound velocity film laminated structure is adopted. Can be made smaller than the case where is used as a surface acoustic wave or the love wave of LiNbO ₃ is used as a surface acoustic wave.

Therefore, when the first filter is the low frequency side filter and the second filter is the high frequency side filter, the reflectance coefficient in the second pass band of the first filter is calculated from the reflectance coefficient in the second pass band of the third filter. Can also be increased. This makes it possible to reduce the insertion loss caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Further, when the love wave generated by LiNbO ₃ is used as a surface acoustic wave in the third filter, a wide bandwidth of the third filter can be secured.

Further, the first pass band is located on the lower frequency side than the second pass band, and each of the first filter and the third filter contains one or more surface acoustic wave resonators, and the first filter and the first filter Each of the surface acoustic wave resonators constituting the third filter is a surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. A leaky wave propagating in the piezoelectric layer made of LiTaO ₃ may be used as a surface acoustic wave, and in the third filter, a love wave propagating in the piezoelectric layer made of LiNbO ₃ may be used as a surface acoustic wave. ..

In the high frequency region than the resonance point and anti-resonance point of the surface acoustic wave resonator, an unnecessary wave is generated due to bulk wave leakage, and the unnecessary wave intensity is higher when the leaky wave of LiTaO ₃ is used as an elastic surface wave. It can be made smaller than the case where the love wave of LiNbO ₃ is used as a surface acoustic wave.

Therefore, when the first filter is the low frequency side filter and the second filter is the high frequency side filter, the reflectance coefficient in the second pass band of the first filter is calculated from the reflectance coefficient in the second pass band of the third filter. Can also be increased. This makes it possible to reduce the insertion loss caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Further, when the love wave generated by LiNbO ₃ is used as a surface acoustic wave in the third filter, a wide bandwidth of the third filter can be secured.

Further, the first pass band is located on the higher frequency side than the second pass band, and each of the first filter and the third filter contains one or more surface acoustic wave resonators. (1) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ are used as surface acoustic waves, (2) Leaky waves propagating in the piezoelectric layer made of LiTaO ₃ are used as surface acoustic waves, and (3) LiNbO. Either the love wave propagating in the piezoelectric layer composed of ₃ is used as an elastic surface wave, (4) the elastic wave resonator is composed of SMR, and (5) the elastic wave resonator is composed of FBAR. In the third filter, the elastic wave resonator has a piezoelectric layer in which an IDT electrode is formed on one main surface, and a bulk wave sound velocity propagating more than the elastic wave sound velocity propagating in the piezoelectric layer. A high-speed treble support substrate and a low-velocity film that is arranged between the treble support substrate and the piezoelectric layer and has a bulk wave sound velocity that is slower than the surface acoustic wave propagating through the piezoelectric layer. It may have a constructed sound velocity film laminated structure.

When the elastic wave resonator has a sonic film laminated structure, Rayleigh wave spurious is generated in the vicinity of 0.76 times the resonance frequency of the elastic wave resonator. Therefore, by adopting a sound velocity film laminated structure for the third filter and not having a sound velocity film laminated structure for the first filter, the low loss property and good temperature characteristics of the third filter are ensured in the second pass band of the first filter. The reflection coefficient can be increased.

Therefore, when the first filter is the high frequency side filter and the second filter is the low frequency side filter, the first filter, the third filter, or the third filter, or the third filter, of the insertion loss in the second pass band of the second filter. Insertion loss due to both can be reduced.

Further, the first pass band is located on the higher frequency side than the second pass band, and each of the first filter and the third filter contains one or more elastic wave resonators. (1) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ are used as elastic surface waves, (2) Love waves propagating in the piezoelectric layer made of LiNbO ₃ are used as elastic surface waves, (3) Elasticity. The wave resonators are a piezoelectric layer in which an IDT electrode is formed on one main surface, a high-sound velocity support substrate in which a bulk wave sound velocity propagating is faster than an elastic wave sound velocity propagating in the piezoelectric layer, and the high sound velocity support substrate. It has a laminated sound velocity film structure composed of a low tone velocity film which is arranged between the sound velocity support substrate and the piezoelectric layer and whose bulk wave sound velocity propagates lower than the elastic wave sound velocity propagating in the piezoelectric layer. 4) The elastic wave resonator is composed of SMR, and (5) The elastic wave resonator is composed of FBAR. In the third filter, the piezoelectric layer made of LiTaO ₃ is propagated. A leaky wave may be used as an elastic surface wave.

When the leaky wave of LiTaO ₃ is used as an elastic wave, a Rayleigh wave spurious is generated in the vicinity of 0.76 times the resonance frequency of the elastic wave resonator. Therefore, by using the leaky wave of LiTaO ₃ as an elastic wave in the third filter and not using the leaky wave of LiTaO ₃ as an elastic wave in the first filter, the reflection coefficient in the second pass band of the first filter is effective. Can be made larger.

Therefore, when the first filter is the high frequency side filter and the second filter is the low frequency side filter, the first filter, the third filter, or the third filter, or the third filter, of the insertion loss in the second pass band of the second filter. Insertion loss due to both can be reduced.

Further, the first pass band is located on the lower frequency side than the second pass band, and each of the first filter and the third filter contains one or more elastic wave resonators, and the first filter includes one or more elastic wave resonators. , (1) The elastic wave resonator supports a piezoelectric layer in which an IDT electrode is formed on one main surface, and a bulk wave sound velocity propagating faster than the elastic wave sound velocity propagating in the piezoelectric layer. Lamination of a sound velocity film composed of a substrate and a low sound velocity film arranged between the high sound velocity support substrate and the piezoelectric layer and having a bulk wave sound velocity lower than the elastic wave sound velocity propagating in the piezoelectric layer. (2) A leaky wave propagating in a piezoelectric layer made of LiTaO ₃ is used as an elastic surface wave, and (3) a love wave propagating in a piezoelectric layer made of LiNbO ₃ is used as an elastic surface wave. Either (4) the elastic wave resonator is composed of SMR, and (5) the elastic wave resonator is composed of FBAR. In the third filter, the piezoelectric layer made of LiNbO ₃ is propagated. Rayleigh waves may be used as elastic surface waves.

When the Rayleigh wave of LiNbO ₃ is used as an elastic wave, a higher-order mode is generated in the vicinity of 1.2 times the resonance frequency of the elastic wave resonator. Therefore, by using the Rayleigh wave of LiNbO ₃ as an elastic wave in the third filter and not using the Rayleigh wave of LiNbO ₃ as an elastic wave in the first filter, the reflection coefficient in the second pass band of the first filter is effective. Can be made larger.

Therefore, when the first filter is the low frequency side filter and the second filter is the high frequency side filter, the first filter, the third filter, or the third filter, or the third filter, of the insertion loss in the second pass band of the second filter. Insertion loss due to both can be reduced.

Further, the first pass band is located on the lower frequency side than the second pass band, and each of the first filter and the third filter contains one or more elastic wave resonators, and the first filter includes one or more elastic wave resonators. , (1) Utilizing a Rayleigh wave propagating in a piezoelectric layer made of LiNbO ₃ as an elastic surface wave, (2) A piezoelectric layer in which an IDT electrode is formed on one main surface of an elastic wave resonator. A high-sound velocity support substrate whose bulk wave sound velocity propagates faster than the elastic wave sound velocity propagating in the piezoelectric layer, and an elastic wave propagating in the piezoelectric layer arranged between the high-sound velocity support substrate and the piezoelectric layer. Bulk wave propagating at a wave velocity slower than the wave sound velocity It has a sound velocity film laminated structure composed of a bass velocity film, and (3) a leaky wave propagating in a piezoelectric layer made of LiTaO ₃ is used as an elastic surface wave. Either (4) the elastic wave resonator is composed of SMR, and (5) the elastic wave resonator is composed of FBAR. In the third filter, the piezoelectric layer made of LiNbO ₃ is propagated. Love waves may be used as elastic surface waves.

When the love wave of LiNbO ₃ is used as an elastic wave, a higher-order mode is generated in the vicinity of 1.2 times the resonance frequency of the elastic wave resonator. Therefore, the third filter uses the LiNbO ₃ love wave and the elastic wave, and the first filter does not use the LiNbO ₃ love wave as the elastic wave, so that the reflection coefficient in the second pass band of the first filter is effective. Can be made larger.

Therefore, when the first filter is the low frequency side filter and the second filter is the high frequency side filter, the first filter, the third filter, or the third filter, or the third filter, of the insertion loss in the second pass band of the second filter. Insertion loss due to both can be reduced.

Further, each of the first filter and the two or more surface acoustic wave resonators constituting the third filter is a surface acoustic wave composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. In the first filter and the third filter, which is a resonator, a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, and the IDT electrode constituting the first filter and the IDT electrode described above. The film thickness or duty may be different from that of the IDT electrode constituting the third filter.

When the leaky wave of LiTaO ₃ is used as an elastic wave, a Rayleigh wave spurious is generated on the low frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the film thickness or duty of the IDT electrode different between the first filter and the third filter, the generation frequency of Rayleigh wave spurious in the first filter is shifted to the outside of the second pass band. Is possible. As a result, the reflectance coefficient in the second pass band of the first filter can be effectively increased, and among the insertion losses in the second pass band of the second filter, the first filter, the third filter, or both of them can be used. The resulting insertion loss can be reduced.

Further, each of the first filter and the two or more elastic wave resonators constituting the third filter is an elastic surface wave composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. It is a resonator, and in the first filter and the third filter, the elastic wave resonator is generated from the piezoelectric layer in which the IDT electrode is formed on one main surface and the elastic wave sound velocity propagating in the piezoelectric layer. The bulk wave sound velocity that propagates is also high, and the bulk wave sound velocity that propagates more than the elastic wave sound velocity that is arranged between the high sound velocity support substrate and the piezoelectric layer and propagates through the piezoelectric layer. It has a sound velocity film laminated structure composed of a low-speed bass velocity film, and in the first filter and the third filter, the film thickness of the IDT electrode, the duty of the IDT electrode, and the film of the bass velocity film. Either the thickness may be different.

When a sonic film laminated structure is adopted, Rayleigh wave spurious is generated on the low frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the film thickness or duty of the IDT electrode different between the first filter and the third filter, the generation frequency of Rayleigh wave spurious in the first filter is shifted to the outside of the second pass band. Is possible. As a result, the reflectance coefficient in the second pass band of the first filter can be effectively increased, which is caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Insertion loss can be reduced.

Further, each of the first filter and the two or more surface acoustic wave resonators constituting the third filter is formed on a substrate having a piezoelectric layer, an IDT electrode formed on the substrate, and the IDT electrode. and a surface acoustic wave resonator made of a protective film, from the the first filter and said third filter, (1) the Rayleigh wave propagating through the piezoelectric layer made of LiNbO _3, or (2) LiNbO ₃ The Rayleigh wave propagating in the piezoelectric layer is used as a surface acoustic wave, and in the first filter and the third filter, the film thickness of the IDT electrode, the duty of the IDT electrode, and the film of the protective film are used. Either the thickness may be different.

Rayleigh waves LiNbO _3, or when utilizing Love waves of LiNbO ₃ as a surface acoustic wave, high-order mode occurs in the high frequency side of the resonance frequency of the elastic wave resonators. On the other hand, by making the film thickness of the IDT electrode, the duty of the IDT electrode, or the film thickness of the bass sound film different between the first filter and the third filter, the generation frequency of the higher-order mode in the first filter can be set. , It becomes possible to shift out of the second pass band. As a result, the reflectance coefficient in the second pass band of the first filter can be effectively increased, which is caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Insertion loss can be reduced.

Further, each of the first filter and the two or more elastic wave resonators constituting the third filter is an elastic surface wave composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. It is a resonator, and in the first filter and the third filter, the elastic wave resonator is generated from the piezoelectric layer in which the IDT electrode is formed on one main surface, and the elastic wave sound velocity propagating in the piezoelectric layer. The bulk wave sound velocity that propagates is also high, and the bulk wave sound velocity that propagates more than the elastic wave sound velocity that is arranged between the high sound velocity support substrate and the piezoelectric layer and propagates through the piezoelectric layer. It has a sound velocity film laminated structure composed of a low-speed low-sound velocity film, the high-sound velocity support substrate is composed of silicon crystals, and the first filter and the third filter have a thickness of the piezoelectric layer. Either the film thickness of the low piezo film and the silicon crystal orientation of the high piezo support substrate may be different.

When the sound velocity film laminated structure is adopted, a high-order mode is generated on the high frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the film thickness of the piezoelectric layer, the film thickness of the low sound velocity film, or the silicon crystal orientation of the hypersonic support substrate different between the first filter and the third filter, the higher order in the first filter is obtained. It is possible to shift the generation frequency of the mode to the outside of the second pass band. As a result, the reflectance coefficient in the second pass band of the first filter can be effectively increased, which is caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Insertion loss can be reduced.

Further, each of the first filter and the two or more surface acoustic wave resonators constituting the third filter is a surface acoustic wave composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate. In the first filter and the third filter, which are resonators, (1) a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ or (2) a love wave propagating in the piezoelectric layer made of LiNbO _3. , Is used as a surface acoustic wave, and the film thickness of the IDT electrode may be different between the first filter and the third filter.

When a leaky wave of LiTaO ₃ or a love wave of LiNbO ₃ is used as an elastic surface wave, a bulk wave (unnecessary wave) is generated on the high frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the film thickness of the IDT electrode different between the first filter and the third filter, it is possible to shift the generation frequency of the bulk wave in the first filter to the outside of the second pass band. Become. As a result, the reflectance coefficient in the second pass band of the first filter can be effectively reduced to a large value, which is caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter. Insertion loss can be reduced.

Further, a first amplifier circuit connected to the first input / output terminal and a second amplifier circuit connected to the second input / output terminal may be further provided.

This makes it possible to reduce the insertion loss caused by the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter in the high-frequency front-end circuit including the amplifier circuit. It becomes.

Further, the communication device according to one aspect of the present invention transmits the high frequency signal between the RF signal processing circuit that processes the high frequency signal transmitted and received by the antenna element and the antenna element and the RF signal processing circuit. The high-frequency front-end circuit described above is provided.

This makes it possible to provide a small communication device in which the insertion loss due to the first filter, the third filter, or both of the insertion losses in the second pass band of the second filter is reduced.

According to the present invention, it is possible to provide a small high-frequency front-end circuit or communication device in which propagation loss of high-frequency signals is reduced even during CA operation.

It is a circuit block diagram of the high frequency front end circuit which concerns on Embodiment 1. FIG. It is a figure explaining the reflection characteristic of the high frequency front end circuit which concerns on Embodiment 1. FIG. It is a figure explaining the problem when two filters are connected in common with a common terminal. It is a circuit block diagram of the demultiplexing circuit which concerns on the modification 1 of Embodiment 1. FIG. It is a circuit block diagram of the demultiplexing circuit which concerns on the modification 2 of Embodiment 1. FIG. It is a circuit block diagram of the demultiplexing circuit which concerns on the modification 3 of Embodiment 1. FIG. FIG. 5 is a circuit configuration diagram of a communication device according to a modification 4 of the first embodiment. It is a circuit block diagram of the high frequency front end circuit which concerns on modification 5 of Embodiment 1. FIG. It is a circuit block diagram of the high frequency front end circuit which concerns on the modification 6 of Embodiment 1. FIG. It is a circuit block diagram of the high frequency front end circuit which concerns on the modification 7 of Embodiment 1. FIG. It is a circuit block diagram of the high frequency front end circuit which concerns on the modification 8 of Embodiment 1. FIG. This is an example of a plan view and a cross-sectional view schematically showing the filter resonator according to the second embodiment. It is a figure explaining the reflection characteristic in the low region 1 of the high frequency front end circuit which concerns on Embodiment 2. FIG. It is a figure which shows the combination of the structure of the 1st filter and the 3rd filter which concerns on Embodiment 2. FIG. It is a figure explaining the bulk wave leakage in the high region 1 of the high frequency front end circuit which concerns on the modification 1 of Embodiment 2. It is a figure which shows the combination of the structure of the 1st filter and the 3rd filter which concerns on the modification 1 of Embodiment 2. It is a figure explaining the generation of spurious in the low region 2 of the high frequency front end circuit which concerns on the modification 2 of Embodiment 2. It is a figure which shows the combination of the structure of the 1st filter and the 3rd filter which concerns on the modification 2 of Embodiment 2. It is a figure explaining the occurrence of the high order mode in the high region 2 of the high frequency front end circuit which concerns on the modification 3 of Embodiment 2. FIG. It is a figure which shows the combination of the structure of the 1st filter and the 3rd filter which concerns on the modification 3 of Embodiment 2. It is a graph which shows the deterioration of the reflection loss by the higher order mode of the 1st filter which concerns on Embodiment 2. FIG. It is a figure which shows the parameter which makes the structure of the 1st filter and the 3rd filter which concerns on the modification 4 of Embodiment 2 different. It is a figure which shows the parameter which makes the structure of the 1st filter and the 3rd filter different according to the 5th modification of Embodiment 2. It is a figure which shows the parameter which makes the structure of the 1st filter and the 3rd filter different according to the modification 6 of Embodiment 2. It is a circuit block diagram of the high frequency front end circuit which concerns on Embodiment 3. FIG. It is a circuit block diagram of the high frequency front end circuit which concerns on a comparative example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that all of the embodiments described below are comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement of components, connection modes, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Of the components in the following embodiments, the components not described in the independent claims are described as optional components. Also, the sizes or ratios of the components shown in the drawings are not always exact.

(Embodiment 1)
[1.1 High-frequency front-end circuit configuration]
FIG. 1A is a circuit configuration diagram of the high frequency front end circuit 1 according to the first embodiment. As shown in the figure, the high-frequency front-end circuit 1 includes a first filter 11, a second filter 12, a third filter 13, a switch 21, an antenna common terminal 101, and input / output terminals 102 and 103. Be prepared. The high-frequency front-end circuit 1 is a composite elastic wave filter device including a first filter 11 and a second filter 12 that are commonly connected by an antenna common terminal 101.

The common terminal 101 can be connected to, for example, an antenna element, and the input / output terminals 102 and 103 can be connected to a high frequency signal processing circuit via an amplifier circuit.

The first filter 11 is a filter having a first terminal and a second terminal, the first terminal being connected to the antenna common terminal 101, and having a first pass band.

The second filter 12 is a filter connected to the antenna common terminal 101, arranged between the antenna common terminal 101 and the input / output terminal 103, and has a second pass band different from the first pass band.

The first filter 11 and the second filter 12 form a demultiplexing / merging circuit.

The switch 21 is a switch circuit having a common terminal 21c, a selection terminal 21a (first selection terminal) and 21b, and the common terminal 21c is connected to the second terminal of the first filter 11.

The third filter 13 is a filter connected to the selection terminal 21a (first selection terminal) and arranged between the switch 21 and the input / output terminal 102.

A filter having a pass band different from that of the third filter may be connected to the selection terminal 21b (second selection terminal) of the switch 21, or an amplifier circuit may be directly connected to the selection terminal 21b (second selection terminal). Further, the number of selection terminals of the switch 21 may be 3 or more. Further, the pass band of the filter connected to the selection terminal 21b (second selection terminal) may overlap with the pass band of the third filter. Even in this case, the switch 21 makes it possible to narrow down the high-frequency signal passing through the first filter 11 to one path via the selection terminal 21a or 21b and propagate it.

Further, the circuit configuration of the second stage of the second filter 12 (opposite to the antenna common terminal 101) may be the same as the circuit configuration of the second stage of the first filter 11, and the switch is not arranged and the circuit configuration is the same. 2 The filter 12 may be directly connected to the amplifier circuit.

FIG. 1B is a diagram for explaining the reflection characteristics of the high-frequency front-end circuit 1 according to the first embodiment. The figure shows the passing characteristics of the first filter 11 and the second filter 12 commonly connected by the antenna common terminal 101, and the reflection characteristics of the first filter 11 and the third filter 13. Here, in the high-frequency front-end circuit 1 according to the present embodiment, the reflectance coefficient in the pass band 12H (second pass band) when the first filter 11 is viewed from the antenna common terminal 101 side alone is the third filter. It is larger than the reflectance coefficient in the pass band 12H (second pass band) when 13 is viewed alone from the common terminal 101 side.

The frequency relationship between the first filter and the third filter is not limited to that the first filter 11 is on the low frequency side and the second filter is on the high frequency side as shown in FIG. 1B, and the first filter 11 May be on the high frequency side and the second filter may be on the low frequency side.

[1.2 Effect of reducing insertion loss of the second filter due to the first filter, the third filter, or both of the high-frequency front-end circuits]
FIG. 2 is a diagram illustrating a problem when two filters (filter A and filter B) are commonly connected by an antenna common terminal. As shown in FIG. 2, a demultiplexing circuit in which the filter A (passband A) and the filter B (passband B) are commonly connected by the antenna common terminal is assumed. Consider the insertion loss of the demultiplexing circuit in this case.

The insertion loss of the pass band A in the filter A is deteriorated by the influence of the filter B in addition to the insertion loss of the filter A itself. Here, of the insertion loss of the filter A, the insertion loss caused by the filter B is affected by the reflection characteristic in the pass band A of the filter B. More specifically, of the insertion loss of the filter A, the insertion loss caused by the filter B is the reflection coefficient when the filter B is viewed from the antenna common terminal side in the filter B before being commonly connected by the antenna common terminal. The larger the value, the smaller the insertion loss caused by the filter B among the insertion losses of the filter A.

When the configuration for reducing the insertion loss due to the filter of the other party connected in common is applied to the high frequency front end circuit 1 according to the present embodiment, the second pass band propagating from the antenna common terminal 101 to the input / output terminal 103. In order to pass the high-frequency signal of It is necessary to increase. That is, in order to reduce the insertion loss caused by the first filter 11, the third filter 13, or both of the insertion losses in the second pass band of the second filter 12, the first filter 11 connected in series is used. And it is necessary to increase the reflectance coefficient in the second pass band when the third filter 13 is viewed from the antenna common terminal 101.

Furthermore, when multiple filters are connected in series, of the filters connected in series, the filter closer to the antenna common terminal has the reflectance coefficient when the filter connected in series is viewed from the antenna common terminal side. Contribution is high. That is, in order to reduce the insertion loss caused by the filter of the other party that is commonly connected among the insertion losses of the second filter 12, the antenna common terminal 101 of the first filter 11 and the third filter 13 that are connected in series is used. It is effective to increase the reflection coefficient in the second pass band of the nearby first filter 11.

On the other hand, while improving the reflection characteristics of the first filter 11 and the third filter 13 connected in series as described above, the passing characteristics, attenuation characteristics, and temperature characteristics of the first filter 11 and the third filter 13 connected in series are improved. , And filter characteristics such as bandwidth must be ensured according to the required specifications. Depending on the filter configuration, the reflection characteristics and the above filter characteristics may not be compatible with each other.

From the above viewpoint, the inventors give priority to increasing the reflection coefficient in the first filter 11 and the third filter 13 which are connected in series and have a large influence on the reflection characteristics, and affect the reflection characteristics. It has been found that the third filter 13 having a small coefficient has a configuration for ensuring filter characteristics such as pass characteristics, attenuation characteristics, temperature characteristics, and bandwidth.

According to the configuration of the high-frequency front-end circuit 1 according to the present embodiment, the reflectance coefficient in the second pass band of the first filter 11 is larger than the reflectance coefficient in the second pass band of the third filter 13. Here, since the third filter 13 arranged in the subsequent stage places more importance on the filter passing characteristic and the attenuation characteristic than the reflection characteristic, the first filter 11, the switch 21, and the third filter 13 are pressed from the antenna common terminal 101 side. The reflection coefficient in the second pass band when viewed can be increased more effectively without deteriorating the filter characteristics of the third filter 13. As a result, of the insertion loss in the second pass band of the second filter 12, without arranging a switch between the antenna element and the demultiplexing / combining circuit composed of the first filter 11 and the second filter 12. Since the insertion loss caused by the first filter 11, the third filter 13, or both can be effectively reduced, a small high-frequency front-end circuit that can maintain low-loss signal propagation characteristics even during CA operation. It becomes possible to provide 1.

The reflection coefficient of the first filter 11 in the second pass band is preferably 0.9 or more.

Further, in the high-frequency front-end circuit 1 according to the present embodiment, the filters commonly connected by the antenna common terminal 101 are not limited to two, the first filter 11 and the second filter 12, and three or more filters are used. The antenna common terminal 101 may be commonly connected.

[1.3 Configuration of demultiplexing / combining circuit according to modified example]
FIG. 3A is a circuit configuration diagram of a demultiplexing circuit according to a first modification of the first embodiment. The figure illustrates the circuit configuration of the triplexer applied to the demultiplexing / merging circuit of the high frequency front-end circuit according to the present embodiment.

The high-frequency front-end circuit according to this modification is an LB (low band: 698-960 MHz) filter 11L and an MBa (middle band: 1710-2200 MHz) filter 11M1 connected to the antenna common terminal 101 as demultiplexing / merging circuits. And an HBa (high band: 2300-2690 MHz) filter 11H1.

That is, the high-frequency front-end circuit according to the first modification includes the first filter 11 and the second filter 12, and further includes a fourth filter connected to the antenna common terminal 101 and having a third pass band. Here, the first filter 11 according to the first embodiment corresponds to any one of the LB filter 11L, the MBa filter 11M1, and the HBa filter 11H1 in this modification.

FIG. 3B is a circuit configuration diagram of a demultiplexing circuit according to a second modification of the first embodiment. The figure illustrates the circuit configuration of the quad plexer applied to the demultiplexing / merging circuit of the high frequency front end circuit according to the present embodiment.

The high-frequency front-end circuit according to this modification is an LB (low band: 698-960 MHz) filter 11L and an MBa (middle band: 1710-2200 MHz) filter 11M1 connected to the antenna common terminal 101 as demultiplexing / merging circuits. The MHBa (middle high band: 2300-2400 MHz) filter 11MH1 and the HBb (middle high band: 2496-2690 MHz) filter 11H2 are provided.

That is, the high-frequency front-end circuit according to the second modification has a fourth filter having a third pass band and a fourth pass band connected to the antenna common terminal 101 in addition to the first filter 11 and the second filter 12. It is provided with a fifth filter having. Here, the first filter 11 according to the first embodiment corresponds to any one of the LB filter 11L, the MBa filter 11M1, the MHBa filter 11MH1, and the HBb filter 11H2 in this modification.

FIG. 3C is a circuit configuration diagram of a demultiplexing circuit according to a modification 3 of the first embodiment. The figure illustrates the circuit configuration of the quad plexer applied to the demultiplexing / merging circuit of the high frequency front end circuit according to the present embodiment.

The high-frequency front-end circuit according to this modification is an MLB (middle low band: 1475.9-2025 MHz) filter 11L1 connected to the antenna common terminal 101 and an MBb (middle band: 2110-2200 MHz) as a demultiplexing / combining circuit. ) Filter 11M2, MHBa (middle high band: 2300-2400MHz or 2300-2370MHz) filter 11MH1, and HBb (middle high band: 2496-2690MHz) filter 11H2.

That is, the high-frequency front-end circuit according to the third modification has a fourth filter having a third pass band and a fourth pass band connected to the antenna common terminal 101 in addition to the first filter 11 and the second filter 12. It is provided with a fifth filter having. Here, the first filter 11 according to the first embodiment corresponds to any one of the MLB filter 11L1, the MBb filter 11M2, the MHBa filter 11MH1, and the HBb filter 11H2 in this modification.

[1.4 Configuration of high-frequency front-end circuit according to Modification 4]
FIG. 4 is a circuit configuration diagram of the communication device 3 according to the modified example 4 of the first embodiment. The figure shows the communication device 3 according to the present embodiment. The communication device 3 is composed of the high frequency front end circuit 2 according to the modification 4 and the high frequency signal processing circuit (RFIC) 40.

The high-frequency front-end circuit 2 includes an antenna common terminal 101, demultiplexing circuits 10 and 14, switches 21 and 22, a filter circuit 15, and an amplifier circuit 30.

The demultiplexing circuit 10 is connected to the antenna common terminal 101, and is composed of a low-pass filter 10A (passband: 699-960 MHz) and a high-pass filter 10B (passband: 1475.9-2690 MHz).

The demultiplexer circuit 14 is connected to the high pass filter 10B and is connected to the MLB filter 11A (1475.9-2025 MHz), the MBb filter 11B (2110-2200 MHz), the MHBa filter 11C (2300-2400 MHz or 2300-2370 MHz), and the HBb filter 11D. It is composed of (2496-2690 MHz).

The switch 21 is composed of switches 21A, 21C, and 21D. The switch 22 is composed of switches 22A, 22B, 22C, and 22D.

The filter circuit 15 is composed of filters 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, 13j, and 13k.

The amplifier circuit is composed of LNA 31, 32, 33, 34, 35, and 36.

The demultiplexing circuit 14 divides the frequency band of the high frequency signal into four frequency band groups. More specifically, the MLB filter 11A passes the signals of Ba (band a), Bb (band b), Bc (band c), Bd (band d), and Be (band e), and the MBb filter 11B passes the signals. The Bp (band p) signal is passed, the MHBa filter 11C is passed the Bf (band f) and Bg (band g) signals, and the HBb filter 11D is Bh (band h), Bj (band j), and Bk. The signal of (band k) is passed.

The common terminal of the switch 21A is connected to the MLB filter 11A, and each selection terminal is connected to the filters 13a (Ba), 13b (Bb), 13c (Bc), and 13d / 13e (Bd / Be).

The common terminal of the switch 21C is connected to the MHBa filter 11C, and each selection terminal is connected to the filters 13f (Bf) and 13g (Bg).

The switch 21D has a common terminal connected to the HBb filter 11D, and each selection terminal connected to the filters 13h (Bh), 13j (Bj), and 13k (Bk).

A common terminal of the switch 22B is connected to the LNA 31, and each selection terminal is connected to the MBb filter 11B and the filter 13d.

The switch 22A has a common terminal connected to the LNA 32 and each selection terminal connected to the filters 13c, 13b, and 13e.

The switch 22D has a common terminal connected to the LNA 33, and each selection terminal connected to the filters 13k, 13h, and 13j.

In the switch 22C, a common terminal is connected to the LNA34, and each selection terminal is connected to the filters 13f and 13g.

The pass band (1475.9-2025 MHz) of the MLB filter 11A is wider than the pass bands of the filters 13a (Ba), 13b (Bb), 13c (Bc), and 13d / 13e (Bd / Be). Each pass band is included. The MBb filter 11B (2110-2200 MHz) includes each pass band of Bp. The MHBa filter 11C (2300-2400 MHz or 2300-2370 MHz) is wider than the respective pass bands of the filters 13f (Bf) and 13 g (Bg) and includes the respective pass bands. The HBb filter 11D (2496-2690 MHz) is wider than the pass bands of the filters 13h (Bh), 13j (Bj), and 13k (Bk) and includes the pass bands.

The high-frequency signal processing circuit (RFIC) 40 is connected to the output terminals of the LNA 31 to 36, processes the high-frequency received signal input from the antenna element via the received signal path of each band, and performs signal processing by down-conversion or the like. The received signal generated by processing is output to the base band signal processing circuit in the subsequent stage. The RF signal processing circuit 40 is, for example, an RFIC. Further, the high frequency signal processing circuit (RFIC) 40 sends control signals S1A, S1C, S1D, S2A, S2B, S2C, and S2D to switches 21A, 21C, 21D, 22A, and 22B, respectively, according to the band used. , 22C, and 22D. As a result, each switch switches the connection of the signal path.

In the communication device 3 having the above configuration, for example, by switching the switches 21A, 21C and 21D, MLB (1475.9-2025 MHz), MBb (2110-2200 MHz), MHBa (2300-2400 MHz or 2300-2370 MHz), and CA operation is possible by selecting one band from each of HBb (2496-2690 MHz).

Here, the configuration of the high-frequency front-end circuit 1 according to the first embodiment can be applied to the high-frequency front-end circuit 2 according to the present modification. That is, as a combination of the first filter 11 and the third filter 13 in the high frequency front-end circuit 1, (1) MLB filter 11A and filter 13a (Ba), (2) MLB filter 11A and filter 13b (Bb), (3). MLB Filter 11A and Filter 13c (Bc), (4) MLB Filter 11A and Filter 13d / 13e (Bd / Be), (5) MHBa Filter 11C and Filter 13f (Bf), (6) MHBa Filter 11C and Filter 13g (6) Bg), (7) HBb filter 11D and filter 13h (Bh), (8) HBb filter 11D and filter 13j (Bj), HBb filter 11D and filter 13k (Bk). Further, as the second filter 12, at least one of the MLB filter 11A, the MBb filter 11B, the MHBa filter 11C, and the HBb filter 11D can be mentioned.

For example, when (1) MLB filter 11A and filter 13a (Ba) are selected as the combination of the first filter 11 and the third filter 13, and MBb filter 11B is selected as the second filter 12, the MLB filter is selected. The reflectance coefficient of 11A at 2110-2200 MHz (pass band of MBb filter 11B) is set to be larger and smaller than the reflectance coefficient of filter 13a at 2110-2200 MHz (pass band of MBb filter 11B).

Further, for example, (1) MLB filter 11A and filter 13a (Ba) are selected as the combination of the first filter 11 and the third filter 13, and the MBb filter 11B, the MHBa filter 11C, and the HBb filter are selected as the second filter 12. When 3 filters of 11D are selected, the MLB filter 11A has 2110-2200 MHz (MBb filter 11B passband), 2300-2400 MHz or 2300-2370 MHz (MHBa filter 11C passband), and 2496-2690 MHz (HBb). The reflectance in the pass band of the filter 11D) is set to be larger than the reflectance of the filter 13a in 2110-2200 MHz, 2300-2400 MHz or 2300-2370 MHz, and 2496-2690 MHz.

According to the above configuration, even if the number of bands operated by CA is increased, the relationship between the reflection characteristics of the demultiplexing circuit 14 and the filter circuit 15 is determined by the reflection of the first filter 11 and the third filter 13 in the first embodiment. By setting the relationship of characteristics, for example, it is possible to correspond to all CA combinations specified in the 3GPP standard. Further, by setting the relationship between the reflection characteristics of the demultiplexing circuit 14 and the filter circuit 15, the band corresponding to the filter circuit 15 in the subsequent stage can be easily changed. Therefore, it is possible to provide a module having an optimum band configuration for each destination with a simplified circuit design.

In this modification, a high-frequency front-end circuit for reception that receives a high-frequency signal from the antenna element and transmits it to the high-frequency signal processing circuit 40 is illustrated, but it is a high-frequency front-end circuit for transmission or transmission / reception. You may. In the case of a high frequency front end circuit for transmission, the amplifier circuit 30 is composed of a power amplifier. Further, in the case of a high-frequency front-end circuit for transmission / reception, the filter circuit 15 is composed of duplexers assigned to each band.

[1.5 Configuration of high-frequency front-end circuit according to modification 5]
FIG. 5A is a circuit configuration diagram of the high frequency front end circuit 2A according to the fifth modification of the first embodiment. The high-frequency front-end circuit 2A according to the present modification is different from the high-frequency front-end circuit 2 according to the modification 4 in that the filters 13g and 13k are not arranged. Hereinafter, the same points as the high frequency front end circuit 2 according to the modification 4 will be omitted from the description of the high frequency front end circuit 2A according to the modification, and the differences will be mainly described.

In the high-frequency front-end circuit 2A, when the pass band of the MHBa filter 11C is 2300-2370 MHz, for example, the pass band of B40a (corresponding to Bg: pass band 2300-2370 MHz) arranged after the MHBa filter 11C. Match. On the other hand, the filter 13f arranged after the MHBa filter 11C corresponds to, for example, B30 (pass band 2350-2360 MHz) and is included in the pass band 2300-2370 MHz of the MHBa filter 11C. Here, since the passing characteristic of the signal of B40a is sufficient for the passing characteristic of the MHBa filter 11C, it is not necessary to arrange the filter 13g on the signal path of B40a. Therefore, in a configuration including a demultiplexing circuit 14 (quad regulator) compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of low-loss signal propagation characteristics even during CA operation is provided. realizable.

When the pass band of the MHBa filter 11C is 2300-2400 MHz in the high-frequency front-end circuit 2A, for example, the pass band of B40 (corresponding to Bg: pass band 2300-2400 MHz) arranged after the MHBa filter 11C is passed. It matches the band. On the other hand, the filter 13f arranged after the MHBa filter 11C corresponds to, for example, B30 (pass band 2350-2360 MHz) and is included in the pass band 2300-2400 MHz of the MHBa filter 11C. Here, since the passing characteristic of the signal of B40 is sufficient with the passing characteristic of the MHBa filter 11C, it is not necessary to arrange the filter 13g on the signal path of B40. Therefore, in a configuration including a demultiplexing circuit 14 (quad regulator) compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of low-loss signal propagation characteristics even during CA operation is provided. realizable.

Further, in the high frequency front end circuit 2A, the pass band of the HBb filter 11D is 2496-2690 MHz, which coincides with the pass band of the B41 arranged after the HBb filter 11D. On the other hand, the filter 13h arranged after the HBb filter 11D corresponds to, for example, B38 (pass band 2570-2620 MHz) and is included in the pass band 2496-2690 MHz of the HBb filter 11D. Further, the filter 13j arranged after the HBb filter 11D corresponds to, for example, B7 (pass band 2620-2690 MHz), and is included in the pass band 2496-2690 MHz of the HBb filter 11D. Here, since the passing characteristic of the signal of B41 is sufficient for the passing characteristic of the HBb filter 11D, it is not necessary to arrange the filter 13k on the signal path of B41. Therefore, in a configuration including a demultiplexer circuit 14 (quad regulator) compatible with MLB, MBb, MHBa, and HBb, a smaller high-frequency front-end circuit capable of low-loss signal propagation characteristics even during CA operation is provided. realizable.

[1.6 Configuration of high-frequency front-end circuit according to modification 6]
FIG. 5B is a circuit configuration diagram of the high frequency front end circuit 2B according to the sixth modification of the first embodiment. The high-frequency front-end circuit 2B according to the present modification is different from the high-frequency front-end circuit 2 according to the modification 4 in that a transmission (Tx) bypass path is added. Hereinafter, the same points as the high frequency front end circuit 2 according to the modification 4 will be omitted from the description of the high frequency front end circuit 2B according to the modification, and the differences will be mainly described.

The high-frequency front-end circuit 2B includes an antenna common terminal 101, a demultiplexing circuit 10 (low-pass filter 10A, high-pass filter 10B) and 14 (MLB filter 11A, MBb filter 11B, MHBa filter 11C, HBb filter 11D), and a switch 21 ( A switch 21E, a switch 21C, a switch 21D) and 22 (not shown), a filter circuit 15 (filter 13a-13k), and an amplifier circuit 30 (not shown) are provided.

The switch 21 is composed of switches 21E, 21C, and 21D.

The switch 21E has a common terminal connected to the MLB filter 11A, and each selection terminal has a transmission (Tx) bypass path, filters 13a (Ba), 13b (Bb), 13c (Bc), 13d / 13e (Bd / Be). It is connected to the.

The transmission (Tx) bypass path is a path that propagates the transmission signal of the band belonging to MLB / LMB, and is, for example, a signal of at least one transmission band of band a, band b, band c, band d, and band e. It is a route that propagates.

The pass band (1475.9-2025 MHz) of the MLB filter 11A includes a transmission pass band propagating in the transmission (Tx) bypass path, and filters 13a (Ba), 13b (Bb), 13c (Bc), and 13d /. It is wider than each pass band of 13e (Bd / Be) and includes each pass band. The MBb filter 11B (2110-2200 MHz) includes each pass band of Bp. The MHBa filter 11C (2300-2400 MHz or 2300-2370 MHz) is wider than the respective pass bands of the filters 13f (Bf) and 13 g (Bg) and includes the respective pass bands. The HBb filter 11D (2496-2690 MHz) is wider than the pass bands of the filters 13h (Bh), 13j (Bj), and 13k (Bk) and includes the pass bands.

With the above configuration, the signal path connecting the transmission (Tx) bypass path, the switch 21E, the MLB filter 11A, the high-pass filter 10B, and the antenna common terminal 101 can be used as the transmission signal path.

According to the above configuration, the transmission signal belonging to MLB / LMB and the receiving signal belonging to MB, MHB, and HB can be CA-operated by the antenna connected to the antenna common terminal 101. That is, the antenna connected to the antenna common terminal 101 can be used not only for reception but also as an antenna for both transmission and reception.

In this modification, the transmission (Tx) bypass path is connected to the switch 21E for switching the band in MLB / LMB, but the transmission (Tx) bypass path is connected to the switch 21C for switching the band in MHB, or , The configuration may be connected to the switch 21D for switching the band in the HB.

[Structure of high-frequency front-end circuit according to 1.7 modification 7]
FIG. 5C is a circuit configuration diagram of the high frequency front end circuit 2C according to the modified example 7 of the first embodiment. The high-frequency front-end circuit 2C according to the present modification is different from the high-frequency front-end circuit 2 according to the modification 4 in that a transmission (Tx) path including a transmission filter is added. Hereinafter, the same points as the high frequency front end circuit 2 according to the modification 4 will be omitted from the description of the high frequency front end circuit 2C according to the modification, and the differences will be mainly described.

The high-frequency front-end circuit 2C includes an antenna common terminal 101, demultiplexing circuits 10 (low-pass filter 10A, high-pass filter 10B) and 14 (MLB filter 11A, MBb filter 11B, MHBa filter 11C, HBb filter 11D), and a switch 21 ( A switch 21F, a switch 21C, a switch 21D) and 22 (not shown), a filter circuit 15 (filter 13a-13k and a transmission filter 13t), and an amplifier circuit 30 (not shown) are provided.

The switch 21 is composed of switches 21F, 21C, and 21D.

In the switch 21F, a common terminal is connected to the MLB filter 11A, and each selection terminal is connected to a transmission (Tx) path, filters 13a (Ba), 13b (Bb), 13c (Bc), 13d / 13e (Bd / Be). It is connected. The switch 21F is a switch capable of connecting a common terminal and two or more selection terminals at the same time.

A transmission filter 13t is arranged on the transmission (Tx) path.

The pass band (1475.9-2025 MHz) of the MLB filter 11A is from each pass band of the transmission filter 13t, the filters 13a (Ba), 13b (Bb), 13c (Bc), and 13d / 13e (Bd / Be). Also broadly covers each pass band. The MBb filter 11B (2110-2200 MHz) includes each pass band of Bp. The MHBa filter 11C (2300-2400 MHz or 2300-2370 MHz) is wider than the respective pass bands of the filters 13f (Bf) and 13 g (Bg) and includes the respective pass bands. The HBb filter 11D (2496-2690 MHz) is wider than the pass bands of the filters 13h (Bh), 13j (Bj), and 13k (Bk) and includes the pass bands.

With the above configuration, the transmission signal path connecting the transmission (Tx) path, the switch 21F, the MLB filter 11A, the high-pass filter 10B, and the antenna common terminal 101, the antenna common terminal 101, the high-pass filter 10B, the MLB filter 11A, the switch 21F, and , And the received signal path connecting any of the filters 13a to 13e can be used at the same time. This makes it possible to transmit and receive simultaneously in the same band. Further, the antenna connected to the antenna common terminal 101 can be used not only for reception but also as an antenna for both transmission and reception.

Further, it is assumed that the transmission (Tx) path is also connected to a high frequency front end circuit different from the high frequency front end circuit 2C. In this case, the high frequency front end circuit 2C and the different high frequency front end circuit are used. It is possible to perform a so-called two-uplink transmission operation with two antennas in the two systems of.

In this modification, the transmission (Tx) path is connected to the switch 21F that switches the band in MLB / LMB, but the transmission (Tx) path switches the band in MHB switch 21C or HB. It may be configured to be connected to a switch 21D for switching the inner band.

[Configuration of high-frequency front-end circuit according to 1.8 Modification Example 8]
FIG. 5D is a circuit configuration diagram of the high frequency front end circuit 2D according to the modified example 8 of the first embodiment. The high-frequency front-end circuit 2D according to the present modification is different from the high-frequency front-end circuit 2 according to the modification 4 in that a transmission / reception (Tx / Rx) path including a duplexer is added. Hereinafter, the same points as the high frequency front end circuit 2 according to the modification 4 will be omitted from the description of the high frequency front end circuit 2D according to the modification, and the differences will be mainly described.

The high-frequency front-end circuit 2D includes an antenna common terminal 101, a demultiplexer circuit 10 (low-pass filter 10A, high-pass filter 10B) and 14 (MLB filter 11A, MBb filter 11B, MHBa filter 11C, HBb filter 11D), and a switch 21 ( It includes a switch 21G, a switch 21C, a switch 21D) and 22 (not shown), a filter circuit 15 (filter 13a-13k), and an amplifier circuit 30 (not shown).

The switch 21 is composed of switches 21G, 21C, and 21D.

In the switch 21G, a common terminal is connected to the MLB filter 11A, and each selection terminal has a transmission / reception (Tx / Rx) path, filters 13a (Ba), 13b (Bb), 13c (Bc), 13d / 13e (Bd / Be). )It is connected to the.

A duplexer composed of a transmission filter 13t1 and a reception filter 13r1 is arranged in the transmission / reception (Tx / Rx) path.

The pass band (1475.9-2025 MHz) of the MLB filter 11A is a duplexer arranged in the transmission / reception (Tx / Rx) path, filters 13a (Ba), 13b (Bb), 13c (Bc), 13d / 13e ( It is wider than each pass band of Bd / Be) and includes each pass band. The MBb filter 11B (2110-2200 MHz) includes each pass band of Bp. The MHBa filter 11C (2300-2400 MHz or 2300-2370 MHz) is wider than the respective pass bands of the filters 13f (Bf) and 13 g (Bg) and includes the respective pass bands. The HBb filter 11D (2496-2690 MHz) is wider than the pass bands of the filters 13h (Bh), 13j (Bj), and 13k (Bk) and includes the pass bands.

With the above configuration, it is possible to use the signal path connecting the transmission / reception (Tx / Rx) path, the switch 21G, the MLB filter 11A, the high-pass filter 10B, and the antenna common terminal 101. As a result, it is possible to simultaneously transmit and receive the transmission signal and the reception signal of the same band propagating along the transmission / reception (Tx / Rx) path. Further, the antenna connected to the antenna common terminal 101 can be used not only for reception but also as an antenna for both transmission and reception.

Further, it is assumed that the transmission / reception (Tx / Rx) path is also connected to a high frequency front end circuit different from the high frequency front end circuit 2D. In this case, the high frequency front end circuit 2D and the different high frequency front end are connected. With two systems with a circuit, it is possible to perform a so-called two-uplink transmission operation with two antennas.

In this modification, the transmission / reception (Tx / Rx) path is connected to the switch 21G that switches the band in MLB / LMB, but the transmission / reception (Tx / Rx) path switches the band in MHB. Alternatively, it may be configured to be connected to a switch 21D for switching a band in the HB.

(Embodiment 2)
In the first embodiment, in a configuration in which the first filter 11 and the second filter 12 are commonly connected by an antenna common terminal, and the first filter 11 and the third filter 13 are connected in series via a switch, the reflection characteristic is obtained. The first filter 11, which has a large influence, gives priority to increasing the reflection coefficient, and the third filter 13, which has a small influence on the reflection characteristics, secures filter characteristics such as pass characteristics, attenuation characteristics, temperature characteristics, and bandwidth. It was explained that it is preferable to take. In the present embodiment, from the above viewpoint, the combination of the structures of the first filter 11 and the third filter 13 will be illustrated.

In the present embodiment, the first filter 11 and the third filter 13 are composed of elastic wave resonators and may have a ladder type filter structure. In this case, one or more elastic wave resonators arranged on the antenna common terminal 101 side include at least one of a series arm resonator and a parallel arm resonator. As a result, while ensuring low loss of the first filter 11 and the third filter 13, of the insertion loss in the second pass band of the second filter 12, the first filter 11, the third filter 13, or both of them. The insertion loss caused by the above can be reduced.

Further, the first filter 11 and the third filter 13 may have a vertically coupled filter structure. This makes it possible to adapt the first filter 11 and the third filter 13 to the filter characteristics that require attenuation enhancement and the like.

Further, as the structure of the surface acoustic wave resonator, FBAR (Film Bulk Acoustic) using surface acoustic wave (SAW: Surface Acoustic Wave) resonator, SMR (Solidly Mountain Resonator), and BAW (Bulk Acoustic Wave) is used. Illustrated.

Here, each of the first filter 11 and the third filter 13 includes two or more elastic wave resonators, and is arranged on the antenna common terminal 101 side of the two or more elastic wave resonators constituting the first filter 11. The reflectance coefficient in the second pass band when one or more elastic wave resonators are viewed alone from the antenna common terminal 101 side is common to the antenna among the two or more elastic wave resonators constituting the third filter 13. One or more elastic wave resonators arranged on the terminal 101 side may be larger than the reflectance coefficient in the second pass band when viewed from the antenna common terminal 101 side as a single unit.

In a filter composed of a plurality of elastic wave resonators, the reflectance coefficient seen from the antenna common terminal 101 side is dominated by the reflection coefficient of one elastic wave resonator closest to the antenna common terminal 101. According to this, among the insertion losses in the second pass band of the second filter 12, the insertion loss caused by the first filter 11, the third filter 13, or both can be effectively reduced.

In the following, a combination of specific configurations in which the reflectance coefficient is increased by the first filter 11 in the first stage and the filter characteristics such as pass characteristics, attenuation characteristics, temperature characteristics, and bandwidth are improved by the third filter in the second stage will be illustrated.

First, an example of the structure of the elastic wave resonator will be described.

[2.1 Elastic wave resonator structure]
FIG. 6 is an example of a plan view and a cross-sectional view schematically showing the filter resonator according to the second embodiment. FIG. 6 shows a case where the surface acoustic wave resonators (series arm resonator and parallel arm resonator) according to the present embodiment are, for example, surface acoustic wave (SAW: Surface Acoustic Wave) resonators. Note that the figure illustrates a planar schematic diagram and a schematic cross-sectional view showing the structure of one elastic wave resonator among the plurality of resonators constituting the first filter 11 and the third filter 13. The elastic wave resonator shown in FIG. 6 is for explaining the typical structure of the plurality of resonators, and the number and length of the electrode fingers constituting the electrode are included in this. Not limited.

Each resonator of the first filter 11 and the third filter 13 is composed of a substrate 80 having a piezoelectric layer 83, and IDT (InterDigital Transducer) electrodes 71a and 71b having a comb shape.

As shown in the plan view of FIG. 6, a pair of IDT electrodes 71a and 71b facing each other are formed on the piezoelectric layer 83. The IDT electrode 71a is composed of a plurality of electrode fingers 172a parallel to each other and a bus bar electrode 171a connecting the plurality of electrode fingers 172a. Further, the IDT electrode 71b is composed of a plurality of electrode fingers 172b parallel to each other and a bus bar electrode 171b connecting the plurality of electrode fingers 172b. The plurality of electrode fingers 172a and 172b are formed along a direction orthogonal to the X-axis direction.

Further, the IDT electrode 71 composed of the plurality of electrode fingers 172a and 172b and the bus bar electrodes 171a and 171b has a laminated structure of the adhesion layer 72 and the main electrode layer 73 as shown in the cross-sectional view of FIG. ing.

The adhesion layer 72 is a layer for improving the adhesion between the piezoelectric layer 83 and the main electrode layer 73, and Ti is used as the material, for example. The film thickness of the adhesion layer 72 is, for example, about 10 nm.

As the material of the main electrode layer 73, for example, Al containing 1% of Cu is used. The film thickness of the main electrode layer 73 is, for example, about 130 nm.

The protective film 84 is formed so as to cover the IDT electrodes 71a and 71b. The protective film 84 is a layer for the purpose of protecting the main electrode layer 73 from the external environment, adjusting the frequency temperature characteristics, and improving the moisture resistance, and is, for example, a film containing silicon dioxide as a main component. .. The film thickness of the protective film 84 is, for example, about 30 nm.

The materials constituting the adhesion layer 72, the main electrode layer 73, and the protective film 84 are not limited to the materials described above. Further, the IDT electrode 71 does not have to have the above-mentioned laminated structure. The IDT electrode 71 may be composed of, for example, a metal or alloy such as Ti, Al, Cu, Pt, Au, Ag, or Pd, or may be composed of a plurality of laminates composed of the above metals or alloys. You may. Further, the protective film 84 may not be formed.

Next, the laminated structure of the substrate 80 will be described.

As shown in the lower part of FIG. 6, the substrate 80 includes a hypersonic support substrate 81, a low sound velocity film 82, and a piezoelectric layer 83, and the high sound velocity support substrate 81, the low sound velocity film 82, and the piezoelectric layer 83 are provided. It has a structure (sound velocity film laminated structure) laminated in this order.

The piezoelectric layer 83 is, for example, a 42 ° Y-cut X-propagated LiTaO ₃ piezoelectric single crystal or piezoelectric ceramic (single lithium tantalate cut along a plane whose normal axis is a axis rotated 42 ° from the Y axis with the X axis as the central axis. It is a crystal or ceramic, and is composed of a single crystal or ceramic in which surface acoustic waves propagate in the X-axis direction). In this case, the elastic wave resonator uses a leaky wave as an elastic wave.

Further, the piezoelectric layer 83 is made of, for example, a 128 ° Y-cut X-propagated LiNbO ₃ piezoelectric single crystal or piezoelectric ceramics. In this case, the elastic wave resonator uses the Rayleigh wave as an elastic wave.

Further, the piezoelectric layer 83 is made of, for example, a Y-cut X propagation LiNbO ₃ piezoelectric single crystal or piezoelectric ceramics. In this case, the elastic wave resonator uses the love wave as an elastic wave.

The single crystal material, cut angle, and laminated structure of the piezoelectric layer 83 are appropriately selected according to the required specifications of the filter (filter characteristics such as pass characteristics, attenuation characteristics, temperature characteristics, and bandwidth). ..

The hypersonic support substrate 81 is a substrate that supports the hypersonic film 82, the piezoelectric layer 83, and the IDT electrode 71. The high sound velocity support substrate 81 is a substrate in which the sound velocity of the bulk wave in the high sound velocity support substrate 81 is higher than that of the surface acoustic wave or the surface acoustic wave propagating in the piezoelectric layer 83, and the elastic surface wave is generated. It is confined in the portion where the piezoelectric layer 83 and the low sound velocity film 82 are laminated, and functions so as not to leak below the high sound velocity support substrate 81. The hypersonic support substrate 81 is, for example, a silicon substrate and has a thickness of, for example, 200 μm. The high-frequency support substrate 81 includes (1) aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon, sapphire, sapphire, lithium tantalate, lithium niobate, or a piezoelectric material such as crystal, and (2) alumina. Various ceramics such as zirconia, cozilite, mulite, steatite, or forsterite, (3) magnesia diamond, (4) materials containing each of the above materials as main components, and (5) main components of a mixture of the above materials. It may be composed of any of the materials.

The low sound velocity film 82 is a film in which the sound velocity of the bulk wave in the low sound velocity film 82 is lower than the sound velocity of the elastic wave propagating in the piezoelectric layer 83, and the piezoelectric layer 83 and the high sound velocity support substrate 81 are formed. Placed in between. Due to this structure and the property that the energy is concentrated in the medium in which the surface acoustic wave is essentially low sound velocity, the leakage of the surface acoustic wave energy to the outside of the IDT electrode is suppressed. The bass sound film 82 is, for example, a film containing silicon dioxide as a main component. The thickness of the bass velocity film 82 is, for example, about 500 nm.

According to the above-mentioned sound velocity film laminated structure of the substrate 80, it is possible to significantly increase the Q value at the resonance frequency and the antiresonance frequency as compared with the conventional structure in which the piezoelectric substrate is used as a single layer. That is, since a surface acoustic wave resonator having a high Q value can be constructed, it is possible to construct a filter having a small insertion loss by using the surface acoustic wave resonator.

The high sound velocity support substrate 81 has a structure in which a support substrate and a high sound velocity film in which the sound velocity of the bulk wave propagating is higher than that of the elastic wave of the surface wave or the boundary wave propagating in the piezoelectric layer 83 are laminated. May have. In this case, the support substrate is made of a piezoelectric material such as sapphire, lithium tantalate, lithium niobate, or crystal, alumina, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cozylite, mulite, steatite, forsterite, etc. Various ceramics, dielectrics such as glass, semiconductors such as silicon and gallium nitride, and resin substrates can be used. Further, the treble velocity film includes various types such as aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon nitride, DLC film or diamond, a medium containing the above material as a main component, and a medium containing a mixture of the above materials as a main component. High sonic material can be used.

In the above description, the IDT electrode 71 constituting the elastic wave resonator is formed on the substrate 80 having the piezoelectric layer 83, but the substrate on which the IDT electrode 71 is formed is the piezoelectric layer. It may be a piezoelectric substrate composed of 83 single layers. The piezoelectric substrate in this case is composed of, for example, a piezoelectric single crystal of LiTaO ₃ or another piezoelectric single crystal such as LiNbO ₃ .

Further, as long as the substrate on which the IDT electrode 71 is formed has the piezoelectric layer 83, the substrate may be entirely composed of the piezoelectric layer, or may have a structure in which the piezoelectric layer is laminated on the support substrate.

Here, the design parameters of the IDT electrode 71 will be described. The wavelength of the surface acoustic wave resonator is defined by the wavelength λ which is the repeating period of the plurality of electrode fingers 172a or 172b constituting the IDT electrode 71 shown in the middle of FIG. The electrode pitch is 1/2 of the wavelength λ, the line widths of the electrode fingers 172a and 172b constituting the IDT electrodes 71a and 71b are W, and the space width between the adjacent electrode fingers 172a and the electrode fingers 172b. Is defined as (W + S). Further, as shown in the upper part of FIG. 6, the crossing width L of the IDT electrodes is the overlapping electrode finger lengths of the electrode finger 172a of the IDT electrode 71a and the electrode finger 172b of the IDT electrode 71b when viewed from the X-axis direction. Is. Further, the electrode duty of each resonator is the line width occupancy of the plurality of electrode fingers 172a and 172b, and is the ratio of the line width to the added value of the line width and the space width of the plurality of electrode fingers 172a and 172b. , W / (W + S).

[2.2 Elastic wave resonator structure_reflection coefficient in low frequency 1]
Hereinafter, a combination of specific configurations in which the reflection coefficient is increased by the first filter 11 and the filter characteristics such as the pass characteristic, the attenuation characteristic, the temperature characteristic, and the bandwidth are improved by the third filter 13 will be illustrated.

FIG. 7A is a diagram for explaining the reflection characteristics in the low frequency range 1 of the high frequency front-end circuit according to the second modification of the second embodiment. As shown in the lower part of the figure, in the impedance characteristics of the elastic wave resonator, a resonance point where the impedance is the minimum value and an antiresonance point where the impedance is the maximum value are confirmed. Here, in the region on the lower frequency side than the resonance point (low frequency 1 in FIG. 7A), the impedance differs depending on the structure of the elastic wave resonator, and the superiority or inferiority of the reflection characteristic exists depending on the magnitude of the impedance. More specifically, (1) a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ , (2) a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ , and (3) a piezoelectric layer made of LiNbO ₃ The structure that utilizes either of the propagating Rayleigh waves as a surface acoustic wave, and (4) the above-mentioned sound velocity film laminated structure, have a larger reflection coefficient loss in the low frequency band 1 than that of SMR or FBAR.

FIG. 7B is a diagram showing a combination of configurations of the first filter 11 and the third filter 13 according to the second embodiment.

From the relationship of the reflection coefficient, when the first pass band of the first filter 11 is located on the higher frequency side than the second pass band of the second filter 12, as shown in FIG. 7B, the high frequency according to the present embodiment. In the front-end circuit, in the first filter 11, from (1) a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ , (2) a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ , and (3) from LiNbO _3. A structure may be used in which any of the Rayleigh waves propagating in the piezoelectric layer is used as a surface acoustic wave.

As a result, in the high-frequency front-end circuit, the reflectance coefficient in the second pass band of the first filter 11 (pass band of the second filter 12) is changed to the second pass band of the third filter 13 (pass band of the second filter 12). It is possible to make it larger than the reflectance coefficient in. As a result, among the insertion losses in the second pass band of the second filter 12, the insertion loss due to the first filter 11, the third filter 13, or both can be reduced.

On the other hand, in the third filter 13, the elastic wave resonator may be composed of SMR or FBAR.

As a result, while increasing the reflection coefficient of the second filter 12 by the configuration of the first filter 11, the low loss property of the second filter 12 and the steepness of the pass band can be ensured by the configuration of the third filter 13.

Further, as shown in FIG. 7B, each of the elastic wave resonators constituting the first filter 11 has the above-mentioned sound velocity film laminated structure, and in the third filter 13, the elastic wave resonator is composed of SMR or FBAR. May be done.

As a result, in the high-frequency front-end circuit, the reflectance coefficient in the second pass band of the first filter 11 (pass band of the second filter 12) is changed to the second pass band of the third filter 13 (pass band of the second filter 12). It is possible to make it larger than the reflectance coefficient in. Therefore, among the insertion losses in the second pass band of the second filter 12, the insertion loss due to the first filter 11, the third filter 13, or both can be reduced. The configuration of the first filter 11 increases the reflection coefficient of the second filter 12, while the configuration of the third filter 13 ensures low loss of the second filter 12 and steepness of the pass band.

[2.3 Elastic wave resonator structure_Bulk wave leakage in high frequency 1]
FIG. 8A is a diagram illustrating bulk wave leakage in the high frequency range 1 of the high frequency front-end circuit according to the first modification of the second embodiment. As shown in the lower part of the figure, in the region on the high frequency side (high frequency 1 in FIG. 8A) of the elastic wave resonator, the impedance changes due to bulk wave leakage (unnecessary wave), and the impedance changes. There are superiority and inferiority of reflection characteristics according to the change of. More specifically, the reflection loss due to bulk wave leakage in the high frequency range 1 is, in ascending order, (1) a structure using Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ as elastic waves, SMR, FBAR. , (2) Sonic film laminated structure, (3) Structure that uses Rayleigh waves propagating in the piezoelectric layer made of LiTaO ₃ as elastic waves, (4) Love waves propagating in the piezoelectric layer made of LiNbO ₃ are elastic waves. It becomes a structure to be used as.

FIG. 8B is a diagram showing a combination of configurations of the first filter 11 and the third filter 13 according to the first modification of the second embodiment.

When the first pass band of the first filter 11 is located on the lower frequency side than the second pass band of the second filter 12 due to the superiority or inferiority of the reflection loss, as shown in FIG. 8B, the high frequency front end circuit In the first filter 11 on the low frequency side, (1) a structure using a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ as an elastic surface wave, (2) an elastic wave resonator composed of an SMR, and ( 3) The surface acoustic wave resonator may be composed of FBAR.

As a result, in the high-frequency front-end circuit, the reflection coefficient in the second pass band of the first filter 11 on the low frequency side (pass band of the second filter 12 on the high frequency side) is changed to the second pass band (high frequency) of the third filter 13. It is possible to make it larger than the reflection coefficient in the pass band of the second filter 12 on the side). Therefore, among the insertion losses in the second pass band of the second filter 12, the insertion loss due to the first filter 11, the third filter 13, or both can be reduced.

On the other hand, the third filter 13 has (1) the above-mentioned sound velocity film laminated structure, (2) a structure using a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ as a surface acoustic wave, and (3) a piezoelectric wave made of LiNbO _3. It may have any of the structures that utilize the surface acoustic wave propagating in the body layer as a surface acoustic wave.

As a result, when the third filter 13 has a sound velocity film laminated structure while increasing the reflectance coefficient of the first filter 11 by the configuration of the first filter 11, the low loss property and good temperature characteristics of the third filter 13 are obtained. Can be secured. Further, when the love wave generated by LiNbO ₃ is used as a surface acoustic wave in the third filter 13, a wide bandwidth of the third filter 13 can be secured.

Further, in the first filter 11, the surface acoustic wave resonator has the above-mentioned sound velocity film laminated structure, and in the third filter 13, the leaky wave propagating in the piezoelectric layer made of (1) LiTaO ₃ is used as the surface acoustic wave. Or (2) a structure that uses a surface acoustic wave propagating in a piezoelectric layer made of LiNbO ₃ as a surface acoustic wave may be provided.

As a result, in the high-frequency front-end circuit, the reflection coefficient in the second pass band of the first filter 11 on the low frequency side (pass band of the second filter 12 on the high frequency side) is changed to the second pass band (high frequency) of the third filter 13. It is possible to make it larger than the reflection coefficient in the pass band of the second filter 12 on the side). Therefore, among the insertion losses in the second pass band of the second filter 12, the insertion loss due to the first filter 11, the third filter 13, or both can be reduced. Further, when the love wave generated by LiNbO ₃ is used as a surface acoustic wave in the third filter 13, a wide bandwidth of the third filter 13 can be secured.

Further, the first filter 11 has a structure in which a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, and the third filter 13 has a love wave propagating in the piezoelectric layer made of LiNbO _3. May have a structure that utilizes as a surface acoustic wave.

Therefore, in the high-frequency front-end circuit, the reflectance coefficient in the second pass band of the first filter 11 on the low frequency side (pass band of the second filter 12 on the high frequency side) is set to the second pass band (high frequency side) of the third filter 13. It is possible to make it larger than the reflection coefficient in the pass band of the second filter 12). As a result, among the insertion losses in the second pass band of the second filter 12, the insertion loss due to the first filter 11, the third filter 13, or both can be reduced. Further, when the love wave generated by LiNbO ₃ is used as a surface acoustic wave in the third filter 13, a wide bandwidth of the third filter 13 can be secured.

[2.4 Elastic wave resonator structure_spurious in low frequency 2]
FIG. 9A is a diagram illustrating the generation of spurious in the low frequency range 2 of the high frequency front-end circuit according to the second modification of the second embodiment. As shown in the lower part of the figure, in the region on the lower frequency side than the resonance point of the elastic wave resonator (low frequency 2 in FIG. 9A), particularly, the above-mentioned sound velocity film laminated structure or the piezoelectric layer made of LiTaO ₃ is formed. In a structure in which a leaky wave propagating is used as an elastic wave, a Rayleigh wave spurious is generated in the vicinity of 0.76 times the resonance frequency. The impedance changes due to the generation of spurious, and the reflection coefficient decreases according to the change in the impedance.

FIG. 9B is a diagram showing a combination of configurations of the first filter and the third filter according to the second modification of the second embodiment.

When the first pass band of the first filter 11 is located on the higher frequency side than the second pass band of the second filter 12, as shown in FIG. 9B, the first filter 11 is a piezoelectric body composed of (1) LiNbO _3. A structure that uses Rayleigh waves propagating in the body layer as surface acoustic waves, (2) a structure that uses leaky waves propagating in the piezoelectric layer made of LiTaO ₃ as surface acoustic waves, and (3) a piezoelectric layer made of LiNbO _3. The structure uses the Rayleigh wave propagating as an elastic surface wave, (4) the surface acoustic wave resonator is composed of SMR, and (5) the surface acoustic wave resonator is composed of FBAR. In the 3 filter 13, the surface acoustic wave resonator may have the above-mentioned sound velocity film laminated structure.

That is, by making the third filter 13 have a sound velocity film laminated structure and not having the first filter 11 having a sound velocity film laminated structure, the second pass band of the first filter 11 (pass band of the second filter 12 on the low frequency side) The reflection coefficient can be increased. Therefore, in the high-frequency front-end circuit, it is possible to reduce the insertion loss due to the first filter 11, the third filter 13, or both of the insertion losses in the second pass band of the second filter 12.

Further, as shown in FIG. 9B, the first filter 11 has a structure in which (1) a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ is used as a surface acoustic wave, and (2) a piezoelectric layer made of LiNbO ₃ is used. A structure that uses the propagating Rayleigh wave as an elastic surface wave, (3) the above-mentioned sound velocity film laminated structure, (4) the elastic wave resonator is composed of SMR, and (5) the elastic wave resonator is composed of FBAR. , And the third filter 13 may have a structure in which a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave.

That is, the third filter 13 uses the leaky wave of LiTaO ₃ as an elastic wave, and the first filter 11 does not use the leaky wave of LiTaO ₃ as an elastic wave, so that the second pass band (low frequency) of the first filter 11 is used. The reflection coefficient in the pass band of the second filter 12 on the side) can be increased. Therefore, in the high-frequency front-end circuit, it is possible to reduce the insertion loss due to the first filter 11, the third filter 13, or both of the insertion losses in the second pass band of the second filter 12.

[2.5 Elastic wave resonator structure_higher-order mode in high frequency 2]
FIG. 10A is a diagram illustrating the generation of a higher-order mode in the high frequency range 2 of the high-frequency front-end circuit according to the third modification of the second embodiment. As shown in the lower part of the figure, in the region on the high frequency side of the resonance point of the surface acoustic wave resonator (high frequency 2 in FIG. 10A), the Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ is an elastic surface wave. structure used as, or in the structure utilizing the Love wave propagating piezoelectric layer made of LiNbO ₃ as a surface acoustic wave, high-order mode is generated in the vicinity of 1.2 times the resonant frequency. The impedance changes due to the generation of this higher-order mode, and the reflection coefficient decreases according to the change in the impedance.

FIG. 10B is a diagram showing a combination of configurations of the first filter 11 and the third filter 13 according to the third modification of the second embodiment.

When the first pass band of the first filter 11 is located on the lower frequency side than the second pass band of the second filter 12, as shown in FIG. 10B, the first filter 11 is (1) laminated with the above-mentioned sound velocity film. Structure, (2) a structure that uses a leaky wave propagating in a piezoelectric layer made of LiTaO ₃ as a surface acoustic wave, and (3) a structure that uses a love wave propagating in a piezoelectric layer made of LiNbO ₃ as a surface acoustic wave. Even if it has either (4) SMR or (5) FBAR and the third filter 13 has a structure that uses a surface acoustic wave propagating in the piezoelectric layer made of LiNbO ₃ as a surface acoustic wave. Good.

That is, the third filter 13 uses the Rayleigh wave of LiNbO ₃ as an elastic wave, and the first filter 11 does not use the Rayleigh wave of LiNbO ₃ as an elastic wave, so that the second pass band (high frequency side) of the first filter 11 is used. The reflection coefficient in the pass band of the second filter 12) can be increased. Therefore, in the high-frequency front-end circuit, it is possible to reduce the insertion loss due to the first filter 11, the third filter 13, or both of the insertion losses in the second pass band of the second filter 12.

Further, as shown in FIG. 10B, the first filter 11 has (1) a structure that utilizes Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ as surface acoustic waves, (2) the above-mentioned sound velocity film laminated structure, and (3). ) It has one of (4) SMR and (5) FBAR, which uses a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ as a surface acoustic wave, and in the third filter 13, from LiNbO _3. It may have a structure in which a Rayleigh wave propagating in the piezoelectric layer is used as a surface acoustic wave.

That is, the third filter 13 uses the love wave of LiNbO ₃ as an elastic wave and the first filter 11 does not use the love wave of LiNbO ₃ as an elastic wave, so that the second pass band (high frequency side) of the first filter 11 is used. The reflection coefficient in the pass band of the second filter 12) can be increased. Therefore, in the high-frequency front-end circuit, it is possible to reduce the insertion loss due to the first filter 11, the third filter 13, or both of the insertion losses in the second pass band of the second filter 12.

[2.6 Adjustment of elastic wave resonator structural parameters]
FIG. 11A is a graph showing the deterioration of the reflection loss due to the higher-order mode of the first filter 11 according to the second embodiment. As shown in the figure, the reflection loss of the first filter 11 seen from the antenna common terminal 101 (Port1) is increased by the higher-order mode on the high frequency side of the resonance point (broken line region in FIG. 11A). Here, the frequency at which the reflection loss increases due to the higher-order mode can be shifted to the high frequency side or the low frequency side by changing the structural parameters of the elastic wave resonator. Alternatively, by changing the structural parameters of the elastic wave resonator, it is possible to suppress an increase in reflection loss in the higher-order mode.

From this point of view, in the first filter 11, which has a large influence on the reflection characteristics, the generation frequencies of higher-order modes and spears are shifted out of the pass band of the second filter 12 by changing the structural parameters. In the third filter 13, which has a small influence on the reflection characteristics, it has been found that the structural parameters are optimized in order to secure the filter characteristics such as the pass characteristic, the attenuation characteristic, the temperature characteristic, and the bandwidth.

FIG. 11B is a diagram showing parameters that make the structures of the first filter 11 and the third filter 13 different according to the modified example 4 of the second embodiment.

Each of the elastic wave resonators constituting the first filter 11 is an elastic surface wave resonator composed of a substrate 80 having a piezoelectric layer 83 and an IDT electrode 71 formed on the substrate. In the first filter 11 and the third filter, as shown in FIG. 11B, the leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, and the IDT electrode 71 constituting the first filter 11 and the third filter The electrode film thickness or duty is different from that of the IDT electrode 71 constituting the 3 filter 13.

When the leaky wave of LiTaO ₃ is used as an elastic wave, a Rayleigh wave spurious is generated on the low frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the electrode thickness or duty of the IDT electrode 71 different between the first filter 11 and the third filter 13, the Rayleigh wave spurious generation frequency in the first filter 11 is set to the second pass band ( It is possible to shift to the outside (pass band of the second filter 12 on the low frequency side). As a result, the reflection coefficient in the second pass band of the first filter 11 (pass band of the second filter 12 on the low frequency side) can be increased, and the first of the insertion losses in the second pass band of the second filter 12 can be increased. Insertion loss due to the filter 11, the third filter 13, or both can be reduced.

Further, in the first filter 11 and the third filter 13, as shown in FIG. 11B, the elastic wave resonator has the above-mentioned sound velocity film laminated structure, and in the first filter 11 and the third filter 13, the IDT electrode 71 Any of the electrode film thickness, the duty of the IDT electrode 71, and the film thickness of the bass velocity film 82 may be different.

When a sonic film laminated structure is adopted, Rayleigh wave spurious is generated on the low frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the electrode thickness or duty of the IDT electrode 71 different between the first filter 11 and the third filter 13, the Rayleigh wave spurious generation frequency in the first filter 11 is set to the second pass band ( It is possible to shift to the outside (pass band of the second filter 12 on the low frequency side). As a result, the reflection coefficient in the second pass band of the first filter 11 (pass band of the second filter 12 on the low frequency side) can be increased, and the first of the insertion losses in the second pass band of the second filter 12 can be increased. Insertion loss due to the filter 11, the third filter 13, or both can be reduced.

FIG. 11C is a diagram showing parameters that make the structures of the first filter 11 and the third filter 13 different according to the fifth modification of the second embodiment.

Each of the surface acoustic wave resonators constituting the first filter 11 and the third filter 13 has a substrate 80 having a piezoelectric layer 83, an IDT electrode 71 formed on the substrate, and protection formed on the IDT electrode 71. It is a surface acoustic wave resonator composed of a film 84. In the first filter 11 and the third filter 13 of the low-frequency side, as shown in FIG. 11C, the Rayleigh wave propagating in the piezoelectric layer made of LiNbO _3, or a Love wave propagating piezoelectric layer made of LiNbO ₃ It is used as a surface acoustic wave, and one of the electrode film thickness of the IDT electrode 71, the duty of the IDT electrode 71, and the film thickness of the protective film 84 is different between the first filter 11 and the third filter 13.

Rayleigh waves LiNbO _3, or when utilizing Love waves of LiNbO ₃ as a surface acoustic wave, high-order mode occurs in the high frequency side of the resonance frequency of the elastic wave resonators. On the other hand, by making the electrode film thickness of the IDT electrode 71, the duty of the IDT electrode 71, or the film thickness of the bass velocity film 82 different between the first filter 11 and the third filter 13, the first filter 11 It is possible to shift the generation frequency of the higher-order mode to the outside of the second pass band (pass band of the second filter 12 on the high frequency side). As a result, the reflection coefficient in the second pass band of the first filter 11 (pass band of the second filter 12 on the high frequency side) can be increased, and the first filter of the insertion loss in the second pass band of the second filter 12 can be increased. Insertion loss due to 11, the third filter 13, or both can be reduced.

Further, in the first filter 11 and the third filter 13, as shown in FIG. 11C, the elastic wave resonator has the above-mentioned sound velocity film laminated structure, the high sound velocity support substrate 81 is made of silicon crystal, and the first filter 11 And the third filter 13, any one of the film thickness of the piezoelectric layer 83, the film thickness of the low sound velocity film 82, and the silicon crystal orientation of the high sound velocity support substrate 81 may be different.

When the sound velocity film laminated structure is adopted, a high-order mode is generated on the high frequency side of the resonance frequency of the elastic wave resonator. On the other hand, the first filter 11 and the third filter 13 are different from each other in the film thickness of the piezoelectric layer 83, the film thickness of the low sound velocity film 82, or the silicon crystal orientation of the high sound velocity support substrate 81. It is possible to shift the generation frequency of the higher-order mode in the 1 filter 11 to the outside of the second pass band (the pass band of the second filter 12 on the high frequency side). As a result, the reflection coefficient in the second pass band of the first filter 11 (pass band of the second filter 12 on the high frequency side) can be increased, and the first filter of the insertion loss in the second pass band of the second filter 12 can be increased. Insertion loss due to 11, the third filter 13, or both can be reduced.

FIG. 12 is a diagram showing parameters that make the structures of the first filter 11 and the third filter 13 different according to the modified example 6 of the second embodiment.

Each of the elastic wave resonators constituting the first filter 11 and the third filter 13 is an elastic surface wave resonator composed of a substrate 80 having a piezoelectric layer 83 and an IDT electrode 71 formed on the substrate. is there. In the first filter 11 and the third filter 13, a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ or a love wave propagating in the piezoelectric layer made of LiNbO ₃ is used as a surface acoustic wave, and the first filter 11 And the third filter 13, the electrode film thickness of the IDT electrode 71 is different.

When a leaky wave of LiTaO ₃ or a love wave of LiNbO ₃ is used as an elastic surface wave, a bulk wave (unnecessary wave) is generated on the high frequency side of the resonance frequency of the elastic wave resonator. On the other hand, by making the electrode film thickness of the IDT electrode 71 different between the first filter 11 and the third filter 13, the generation frequency of the bulk wave in the first filter 11 is set to the second pass band (on the high frequency side). It is possible to shift to the outside (pass band of the second filter 12). As a result, the reflection coefficient in the second pass band of the first filter 11 (pass band of the second filter 12 on the high frequency side) can be increased, and the first filter of the insertion loss in the second pass band of the second filter 12 can be increased. Insertion loss due to 11, the third filter 13, or both can be reduced.

(Embodiment 3)
In the present embodiment, the loss reduction and miniaturization of the high-frequency front-end circuit composed of the demultiplexing circuit connected to the antenna common terminal and the filter corresponding to each band arranged in the subsequent stage of the demultiplexing circuit are reduced. The configuration that realizes the above will be described.

FIG. 13A is a circuit configuration diagram of the high frequency front end circuit 6 according to the third embodiment. The high-frequency front-end circuit 6 shown in the figure includes an antenna common terminal 101, an LB filter 11L, an MB filter 11M, an HB filter 11H, a filter 13b for B3, 13f for B30, and LNA31, 32. And 34.

The LB filter 11L, the MB filter 11M, and the HB filter 11H are demultiplexing circuits connected to the antenna element.

The LB filter 11L is a low-pass pass side filter having a low band band (for example, 2 GHz or less) as a pass band.

The HB filter 11H is a high-frequency pass-side filter having a high-band band (for example, 2.3 GHz or more) as a pass band.

The MB filter 11M is a band-passing type filter having a band 66 (2110-2200 MHz) as a pass band.

The filter 13b is a band-passing type filter having Band 3 (1805-1880 MHz) as a pass band.

The filter 13f is a band-passing type filter having a band 30 (2350-2360 MHz) as a pass band.

Here, the pass band of Band 66 (2110-2200 MHz) includes the pass band of Band 1 (2110-2170 MHz) and the pass band of Band 4 (2110-2155 MHz).

As a result, the signal propagation paths of Band 1 and Band 4 can be shared by the signal propagation path of Band 66. That is, the high frequency signals of Band 1 and Band 4 propagate on the signal path from the MB filter 11M to the LNA 31.

In the above circuit configuration, the combination of CA operations is the CA operation of Band 1 and Band 3 and the CA operation of Band 4 and Band 30. That is, Band 1 and Band 4 having overlapping frequency bands do not operate in CA.

FIG. 13B is a circuit configuration diagram of the high frequency front end circuit 600 according to the comparative example. Conventionally, a high-frequency front-end circuit 600 according to a comparative example has been presented as a circuit configuration for realizing a CA operation between Band 1 and Band 3 and a CA operation between Band 4 and Band 30. The high-frequency front-end circuit 600 includes an antenna common terminal 101, a switch 21, a filter 13p for B1, a filter 13b for B3, a filter 13p for B4, and a filter 13f for B30, and LNA31, 32, 31, and With 34. In this configuration, by switching to the switch 21, the CA operation between Band 1 and Band 3 or the CA operation between Band 4 and Band 30 is selected.

When such a CA operation is performed, as shown in a comparative example, it is common to separately prepare a filter 13p for B1 and a filter 13p for B4, and switch the filter 13p with a switch 21. However, since the pass bands of Band 1 and Band 4 overlap greatly, the filter can be shared by using the wideband MB filter 11M as in the high frequency front-end circuit 6 according to the present embodiment. On the other hand, in the comparative example, waste occurs in the occupied area.

That is, according to the high-frequency front-end circuit 6 according to the present embodiment, the high-frequency signals of Band 1 and Band 4 can be shared by the MB filter 11M having Band 66 as a pass band. As a result, space saving is achieved by realizing the pass band of a plurality of bands with one bandpass filter. Further, since the number of filters through which the high frequency signals of Band 1 and Band 4 pass can be reduced, the propagation loss of the high frequency signals can be improved.

(Other variants, etc.)
The multiplexer, high-frequency front-end circuit, and communication device according to the embodiment of the present invention have been described above with reference to the embodiments and modifications thereof. However, the present invention has any configuration in the embodiments and modifications. Another embodiment realized by combining the elements, a modification obtained by applying various modifications that a person skilled in the art can think of without departing from the gist of the present invention, and a high frequency according to the present invention. Various devices incorporating a front-end circuit and a communication device are also included in the present invention.

For example, in the above description, as a multiplexer, a two-segment / duplex circuit in which two reception signal paths are commonly connected at a common terminal has been described as an example, but the present invention describes, for example, both a transmission path and a reception path. It can also be applied to a circuit including the circuit and a demultiplexing / multiplexing circuit in which three or more signal paths are commonly connected by a common terminal.

Further, in each filter of the multiplexer, an inductor or a capacitor may be connected between each terminal such as an input / output terminal and a ground terminal, and an inductor such as a resistor element and a circuit element other than the capacitor are added. It may have been done.

The present invention can be widely used in communication devices such as mobile phones as low-loss, compact and low-cost multiplexers, high-frequency front-end circuits and communication devices applicable to multi-band and multi-mode frequency standards.

1,2,2A, 2B, 2C, 2D, 6,600 High-frequency front-end circuit 3 Communication device 10,14 Demultiplexer circuit 10A Low-pass filter 10B High-pass filter 11 First filter 11A, 11L1 MLB filter 11B, 11M2 MBb filter 11C, 11MH1 MHBa filter 11D, 11H2 HBb filter 11H HB filter 11H1 HBa filter 11L LB filter 11M MB filter 11M1 MBa filter 11X, 12H Passband 12 2nd filter 13 3rd filter 13a, 13b, 13c, 13d, 13e, 13f, 13g 13h, 13j, 13k, 13p filter 13r1 reception filter 13t, 13t1 transmission filter 15 filter circuit 21, 22, 21A, 21C, 21D, 21E, 21F, 21G, 22A, 22B, 22C, 22D switch 21a, 12b selection terminal 21c common Terminal 30 Amplifier circuit 31, 32, 33, 34, 35, 36 LNA
71, 71a, 71b IDT electrode 72 Adhesion layer 73 Main electrode layer 80 Substrate 81 Hypersonic support substrate 82 Hypersonic film 83 Piezoelectric layer 84 Protective film 101 Antenna common terminal 102, 103 Input / output terminals 171a, 171b Bus bar electrodes 172a, 172b Electrode finger

Claims (31)

Antenna common terminal connected to the antenna element and
The first input / output terminal and the second input / output terminal,
A first filter having a first terminal and a second terminal, having a first pass band, and the first terminal being connected to the antenna common terminal,
A second filter connected to the antenna common terminal, arranged between the antenna common terminal and the second input / output terminal, and having a second pass band different from the first pass band,
A switch that has a common terminal and a plurality of selection terminals, and the common terminal is connected to the second terminal.
A third filter connected to the first selection terminal among the plurality of selection terminals and arranged between the switch and the first input / output terminal is provided.
The reflectance coefficient in the second pass band when the first filter is viewed alone from the antenna common terminal side is in the second pass band when the third filter is viewed alone from the antenna common terminal side. Greater than the reflectance coefficient,
High frequency front end circuit. Each of the first filter and the third filter contains two or more elastic wave resonators.
The second passage when one or more elastic wave resonators arranged on the antenna common terminal side among the two or more elastic wave resonators constituting the first filter are viewed alone from the antenna common terminal side. Regarding the reflectance coefficient in the band, one or more elastic wave resonators arranged on the antenna common terminal side among the two or more elastic wave resonators constituting the third filter are viewed from the antenna common terminal side as a single unit. Greater than the reflectance coefficient in the second pass band of the case,
The high frequency front end circuit according to claim 1. At least one of the first filter and the third filter has a ladder type filter structure.
One or more elastic wave resonators arranged on the antenna common terminal side include at least one of a series arm resonator and a parallel arm resonator.
The high frequency front end circuit according to claim 1 or 2. At least one of the first filter and the third filter has a vertically coupled filter structure.
The high frequency front end circuit according to any one of claims 1 to 3. The second input / output terminal is connected to the second amplifier circuit.
No filter circuit is arranged between the second filter and the second amplifier circuit.
The high frequency front end circuit according to any one of claims 1 to 4. With the third input / output terminal
A fourth filter connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band is further provided.
The first filter, the second filter, and the fourth filter constitute a triplexer.
The first pass band, the second pass band, and the third pass band are applied to the low band (LB: 698-960 MHz), the middle band (MBa: 1710-2200 MHz), and the high band (HBa: 2300-2690 MHz). Being done
The first pass band is any of the low band, the middle band, and the high band.
The high frequency front end circuit according to any one of claims 1 to 5. With the 3rd input / output terminal and the 4th input / output terminal,
A fourth filter connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band,
A fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band is further provided.
The first filter, the second filter, the fourth filter, and the fifth filter constitute a quad plexer.
The first pass band, the second pass band, the third pass band, and the fourth pass band are a low band (LB: 698-960 MHz), a middle band (MBa: 1710-2200 MHz), and a middle high band (MHBa:: 2300-2400MHz), applied to high band (HBb: 2496-2690MHz),
The first pass band is any one of the low band, the middle band, the middle high band, and the high band.
The high frequency front end circuit according to any one of claims 1 to 5. With the 3rd input / output terminal and the 4th input / output terminal,
A fourth filter connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band,
A fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band is further provided.
The first filter, the second filter, the fourth filter, and the fifth filter constitute a quad plexer.
The first pass band, the second pass band, the third pass band, and the fourth pass band are middle low band (MLB: 1475.9-2025 MHz), middle band (MBb: 2110-2200 MHz), and middle high band. (MHBa: 2300-2400MHz or MHBb: 2300-2370MHz), applied to the high band (HBb: 2496-2690MHz),
The first pass band is any one of the middle low band, the middle band, the middle high band, and the high band.
The high frequency front end circuit according to any one of claims 1 to 5. With the 3rd input / output terminal and the 4th input / output terminal,
A fourth filter connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band,
A fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band is further provided.
The first filter, the second filter, the fourth filter, and the fifth filter constitute a quad plexer.
The first pass band, the second pass band, the third pass band, and the fourth pass band are middle low band (MLB: 1475.9-2025 MHz), middle band (MBb: 2110-2200 MHz), and middle high band. (MHBa: 2300-2400MHz or MHBb: 2300-2370MHz), applied to the high band (HBb: 2496-2690MHz),
The first pass band is any of the middle low band, the middle band, and the high band.
The second pass band is the middle high band.
No filter circuit is arranged on the signal path connecting the second filter and the second amplifier circuit.
The high frequency front end circuit according to claim 5. The signal path connecting the second filter and the second amplifier circuit is a path for transmitting and receiving Band 40a (reception band: 2300-2370 MHz).
The high frequency front end circuit according to claim 9. The signal path connecting the second filter and the second amplifier circuit is a path for transmitting and receiving Band 40 (reception band: 2300-2400 MHz).
The high frequency front end circuit according to claim 9. further,
With the 3rd input / output terminal and the 4th input / output terminal,
A fourth filter connected to the antenna common terminal, arranged between the antenna common terminal and the third input / output terminal, and having a third pass band,
A fifth filter connected to the antenna common terminal, arranged between the antenna common terminal and the fourth input / output terminal, and having a fourth pass band is provided.
The first filter, the second filter, the fourth filter, and the fifth filter constitute a quad plexer.
The first pass band, the second pass band, the third pass band, and the fourth pass band are middle low band (MLB: 1475.9-2025 MHz), middle band (MBb: 2110-2200 MHz), and middle high band. (MHBa: 2300-2400MHz or MHBb: 2300-2370MHz), applied to the high band (HBb: 2496-2690MHz),
The first pass band is any one of the middle low band, the middle band, and the middle high band.
The second pass band is the high band.
No filter circuit is arranged on the signal path connecting the second filter and the second amplifier circuit.
The high frequency front end circuit according to claim 5. The signal path connecting the second filter and the second amplifier circuit is a path for transmitting and receiving Band 41 (reception band: 2494-2690 MHz).
The high frequency front end circuit according to claim 10. The first pass band is located on the higher frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
Each of the one or more surface acoustic wave resonators constituting the first filter is a surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter, (1) a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ , (2) a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ , and (3) the piezoelectric wave made of LiNbO _3. Use one of the Rayleigh waves propagating in the body layer as a surface acoustic wave,
The high frequency front end circuit according to any one of claims 1 to 13. In the third filter, the elastic wave resonator is composed of SMR (Solidly Mountain Resonator) or FBAR (Film Bulk Acoustic Resonator).
The high frequency front end circuit according to claim 14. The first pass band is located on the higher frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
Each of the one or more surface acoustic wave resonators constituting the first filter is a surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter, the elastic wave resonator propagates at a speed higher than the elastic wave sound velocity propagating through the piezoelectric layer and the piezoelectric layer having the IDT electrode formed on one of the main surfaces. It is composed of a high-pitched sound support substrate and a low-pitched sound film which is arranged between the high-pitched sound support substrate and the piezoelectric layer and whose bulk wave sound velocity is lower than the elastic wave sound velocity propagating in the piezoelectric layer. Has a sound velocity film laminated structure
In the third filter, the elastic wave resonator is composed of SMR or FBAR.
The high frequency front end circuit according to any one of claims 1 to 13. The first pass band is located on the lower frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
In the first filter, (1) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ are used as elastic surface waves, (2) elastic wave resonators are composed of SMRs, and (3) elastic wave resonances. The child is either composed of FBAR,
The high frequency front end circuit according to any one of claims 1 to 13. In the third filter, (1) the surface acoustic wave resonator propagates at a speed higher than that of the piezoelectric layer in which the IDT electrode is formed on one of the main surfaces and the elastic wave sound velocity propagating in the piezoelectric layer. It is composed of a high-pitched sound support substrate, and a low-pitched sound film which is arranged between the high-pitched sound support substrate and the piezoelectric layer and whose bulk wave sound velocity propagates lower than the surface acoustic wave propagating in the piezoelectric layer. (2) A leaky wave propagating in a piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, and (3) a love wave propagating in a piezoelectric layer made of LiNbO ₃ is elastic. It is either used as a surface wave,
The high frequency front end circuit according to claim 17. The first pass band is located on the lower frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
Each of the first filter and the elastic wave resonator constituting the third filter is an elastic surface wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter, the elastic wave resonator propagates at a speed higher than the elastic wave sound velocity propagating through the piezoelectric layer and the piezoelectric layer having the IDT electrode formed on one of the main surfaces. It is composed of a high-pitched sound support substrate and a low-pitched sound film which is arranged between the high-pitched sound support substrate and the piezoelectric layer and whose bulk wave sound velocity is lower than the elastic wave sound velocity propagating in the piezoelectric layer. Has a sound velocity film laminated structure
In the third filter, (1) a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, or (2) a love wave propagating in the piezoelectric layer made of LiNbO ₃ is used as a surface acoustic wave. Use as a wave,
The high frequency front end circuit according to any one of claims 1 to 13. The first pass band is located on the lower frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
Each of the first filter and the elastic wave resonator constituting the third filter is an elastic surface wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter, a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave.
In the third filter, a surface acoustic wave propagating in the piezoelectric layer made of LiNbO ₃ is used as an elastic surface wave.
The high frequency front end circuit according to any one of claims 1 to 13. The first pass band is located on the higher frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
In the first filter, (1) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ are used as surface acoustic waves, and (2) leaky waves propagating in the piezoelectric layer made of LiTaO ₃ are used as surface acoustic waves. , (3) Utilizes the Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ as an elastic surface wave, (4) The elastic wave resonator is composed of SMR, and (5) The elastic wave resonator is FBAR. Is composed of,
In the third filter, the elastic wave resonator has a high bulk wave sound velocity propagating faster than the elastic wave sound velocity propagating through the piezoelectric layer in which the IDT electrode is formed on one main surface and the piezoelectric layer. A sound velocity composed of a sound velocity support substrate and a bass sound film arranged between the high tone velocity support substrate and the piezoelectric layer and having a bulk wave sound velocity lower than the elastic wave sound velocity propagating in the piezoelectric layer. Has a film laminated structure,
The high frequency front end circuit according to any one of claims 1 to 13. The first pass band is located on the higher frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
In the first filter, (1) Rayleigh waves propagating in the piezoelectric layer made of LiNbO ₃ are used as surface acoustic waves, and (2) love waves propagating in the piezoelectric layer made of LiNbO ₃ are used as surface acoustic waves. (3) The surface acoustic wave resonator propagates in a piezoelectric layer in which an IDT electrode is formed on one of the main surfaces, and the bulk wave sound velocity propagating is faster than the elastic wave sound velocity propagating in the piezoelectric layer. A sound velocity film composed of a support substrate and a low sound velocity film which is arranged between the high sound velocity support substrate and the piezoelectric layer and whose bulk wave sound velocity propagates lower than the surface acoustic wave sound velocity propagating in the piezoelectric layer. It has a laminated structure, (4) the surface acoustic wave resonator is composed of SMR, and (5) the surface acoustic wave resonator is composed of FBAR.
In the third filter, a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave.
The high frequency front end circuit according to any one of claims 1 to 13. The first pass band is located on the lower frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
In the first filter, (1) the bulk wave sound velocity propagated by the elastic wave resonator is faster than the elastic wave sound velocity propagating through the piezoelectric layer in which the IDT electrode is formed on one main surface and the piezoelectric layer. It is composed of a high-sound velocity support substrate, and a low-sound velocity film which is arranged between the high-sound velocity support substrate and the piezoelectric layer and has a bulk wave sound velocity lower than the elastic wave sound velocity propagating in the piezoelectric layer. (2) A leaky wave propagating in a piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave, and (3) a love wave propagating in a piezoelectric layer made of LiNbO ₃ is used as a surface acoustic wave. It is used as a wave, (4) the surface acoustic wave resonator is composed of SMR, and (5) the surface acoustic wave resonator is composed of FBAR.
In the third filter, a Rayleigh wave propagating in the piezoelectric layer made of LiNbO ₃ is used as a surface acoustic wave.
The high frequency front end circuit according to any one of claims 1 to 13. The first pass band is located on the lower frequency side than the second pass band.
Each of the first filter and the third filter contains one or more elastic wave resonators.
In the first filter, (1) a Rayleigh wave propagating in a piezoelectric layer made of LiNbO ₃ is used as an elastic surface wave, and (2) an elastic wave resonator is formed on one main surface of an IDT electrode. The piezoelectric layer, the high-sound velocity support substrate in which the bulk wave sound velocity propagating is faster than the surface acoustic wave propagating in the piezoelectric layer, and the piezoelectric body arranged between the high-sound velocity support substrate and the piezoelectric layer. Surface acoustic wave propagating in the layer Bulk wave propagating at a sound velocity slower than the sound velocity. It has a sound velocity film laminated structure composed of a low-pitched sound film. (3) A leaky wave propagating in a piezoelectric layer made of LiTaO ₃ is an elastic surface. It is used as a wave, (4) the surface acoustic wave resonator is composed of SMR, and (5) the surface acoustic wave resonator is composed of FBAR.
In the third filter, a surface acoustic wave propagating in the piezoelectric layer made of LiNbO ₃ is used as an elastic surface wave.
The high frequency front end circuit according to any one of claims 1 to 13. Each of the first filter and the two or more elastic wave resonators constituting the third filter
A surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter and the third filter, a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ is used as a surface acoustic wave.
The film thickness or duty is different between the IDT electrode constituting the first filter and the IDT electrode constituting the third filter.
The high frequency front end circuit according to any one of claims 1 to 13. Each of the first filter and the two or more elastic wave resonators constituting the third filter
A surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter and the third filter, the elastic wave resonator is a bulk wave propagating from the piezoelectric layer in which the IDT electrode is formed on one main surface and the elastic wave sound velocity propagating through the piezoelectric layer. A high sound velocity support substrate having a high sound velocity, and a low sound velocity whose bulk wave sound velocity, which is arranged between the high sound velocity support substrate and the piezoelectric layer and propagates, is slower than the elastic wave sound velocity propagating through the piezoelectric layer. It has a sound velocity film laminated structure composed of films,
The film thickness of the IDT electrode, the duty of the IDT electrode, and the film thickness of the bass sound film are different between the first filter and the third filter.
The high frequency front end circuit according to any one of claims 1 to 13. Each of the first filter and the two or more elastic wave resonators constituting the third filter
A surface acoustic wave resonator composed of a substrate having a piezoelectric layer, an IDT electrode formed on the substrate, and a protective film formed on the IDT electrode.
In the first filter and said third filter, (1) the Rayleigh wave, or (2) Love wave propagating through the piezoelectric layer made of LiNbO _3, the surface acoustic wave propagating through the piezoelectric layer made of LiNbO ₃ Use as
The film thickness of the IDT electrode, the duty of the IDT electrode, and the film thickness of the protective film are different between the first filter and the third filter.
The high frequency front end circuit according to any one of claims 1 to 13. Each of the first filter and the two or more elastic wave resonators constituting the third filter
A surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter and the third filter, the elastic wave resonator is a bulk wave propagating from the piezoelectric layer in which the IDT electrode is formed on one main surface and the elastic wave sound velocity propagating through the piezoelectric layer. A high sound velocity support substrate having a high sound velocity, and a low sound velocity whose bulk wave sound velocity, which is arranged between the high sound velocity support substrate and the piezoelectric layer and propagates, is slower than the elastic wave sound velocity propagating through the piezoelectric layer. It has a sound velocity film laminated structure composed of films,
The hypersonic support substrate is composed of silicon crystals.
The first filter and the third filter differ in any one of the film thickness of the piezoelectric layer, the film thickness of the hypersonic film, and the silicon crystal orientation of the hypersonic support substrate.
The high frequency front end circuit according to any one of claims 1 to 13. Each of the first filter and the two or more elastic wave resonators constituting the third filter
A surface acoustic wave resonator composed of a substrate having a piezoelectric layer and an IDT electrode formed on the substrate.
In the first filter and the third filter, (1) a leaky wave propagating in the piezoelectric layer made of LiTaO ₃ or (2) a love wave propagating in the piezoelectric layer made of LiNbO ₃ is a surface acoustic wave. Use as
The film thickness of the IDT electrode is different between the first filter and the third filter.
The high frequency front end circuit according to any one of claims 1 to 13. The first amplifier circuit connected to the first input / output terminal and
A second amplifier circuit connected to the second input / output terminal is further provided.
The high frequency front end circuit according to any one of claims 1 to 29. An RF signal processing circuit that processes high-frequency signals transmitted and received by the antenna element, and
The high-frequency front-end circuit according to any one of claims 1 to 30, which transmits the high-frequency signal between the antenna element and the RF signal processing circuit.
Communication device.

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