# US 2017/0288631 A1 · Acoustic wave device

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- Number: US 2017/0288631 A1
- Document ID: US20170288631A1
- Status: Published application
- Kind: A1
- Application number: 15/202,737
- Filed: 2016-07-06
- Published: 2017-10-05
- Earliest claimed: 2016-03-29
- Assignees: Handy International Co., Ltd.
- Applicants: Handy International Co., Ltd.
- Inventors: Kensei UEHARA; Takahiro SATO
- Web page: https://patentgrep.com/patent/US20170288631A1

## CPC

- H03H 9/6483: {Ladder SAW filters}
- H03H 7/0161: {Bandpass filters (H03H7/12 takes precedence)}
- H03H 7/075: Ladder networks, e.g. electric wave filters
- H03H 9/02637: {Details concerning reflective or coupling arrays}
- H03H 9/64: using surface acoustic waves
- H03H 9/6426: {Combinations of the characteristics of different transducers}
- H03H 9/6433: {Coupled resonator filters}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

In order to pass a signal having a wide pass bandwidth with respect to a center frequency of a pass band, a surface acoustic wave device includes a first surface acoustic wave element provided with a first pass band; and a second surface acoustic wave element having a second pass band in a high frequency band compared with the first pass band of the first surface acoustic wave element, in which the first surface acoustic wave element and the second surface acoustic wave element have a common input terminal and a common output terminal, and a frequency of a high frequency side of the first pass band of the first surface acoustic wave element is partially overlapped with a frequency of a low frequency side of the second pass band of the second surface acoustic wave element.

## Claims

### Claim 1

An acoustic wave device comprising:
a first acoustic wave element provided with a first pass band; and
a second acoustic wave element having a second pass band in a high frequency band compared with the first pass band of the first acoustic wave element, wherein
the first acoustic wave element and the second acoustic wave element have a common input terminal and a common output terminal, and
a frequency of a high frequency side of the first pass band of the first acoustic wave element is partially overlapped with a frequency of a low frequency side of the second pass band of the second acoustic wave element.

### Claim 2 (depends on 1)

The device according to claim 1, wherein a frequency of a pass band at the high frequency side of the first pass band is partially overlapped with a frequency of a pass band at the low frequency side of the second pass band, by selecting real parts and imaginary parts of reflection coefficients of the first acoustic wave element and the second acoustic wave element.

### Claim 3 (depends on 2)

The device according to claim 2, wherein if it is assumed that the real part and the imaginary part of the reflection coefficient of the first acoustic wave element are a1 and b1 and the real part and the imaginary part of the reflection coefficient of the second acoustic wave element are a2 and b2 respectively, a relation of a1≧a2 and b1>b2 is established.

### Claim 4 (depends on 1)

The device according to claim 1, wherein at least one of the first acoustic wave element and the second acoustic wave element is an acoustic wave element of a ladder type or a double mode type.

### Claim 5 (depends on 1)

The device according to claim 1, wherein at least any one of the input terminal and the output terminal of the first acoustic wave element and the second acoustic wave element is provided with a parallel arm resonator.

### Claim 6 (depends on 5)

The device according to claim 5, wherein a resonance frequency of the parallel arm resonator is lower than the first pass band.

### Claim 7

An acoustic wave device comprising:
a first acoustic wave element provided with a first pass band; and
a second acoustic wave element having a second pass band in a high frequency band compared with the first pass band of the first acoustic wave element, wherein
the first acoustic wave element and the second acoustic wave element have a common input terminal and a plurality of output terminals, and
a frequency of a high frequency side of the first pass band of the first acoustic wave element is partially overlapped with a frequency of a low frequency side of the second pass band of the second acoustic wave element.

### Claim 8 (depends on 7)

The device according to claim 7, wherein a frequency of a pass band at the high frequency side of the first pass band is partially overlapped with a frequency of a pass band at the low frequency side of the second pass band, by selecting real parts and imaginary parts of reflection coefficients of the first acoustic wave element and the second acoustic wave element.

### Claim 9 (depends on 8)

The device according to claim 8, wherein if it is assumed that the real part and the imaginary part of the reflection coefficient of the first acoustic wave element are a1 and b1 and the real part and the imaginary part of the reflection coefficient of the second acoustic wave element are a2 and b2 respectively, a relation of a1≧a2 and b1>b2 is established.

### Claim 10 (depends on 7)

The device according to claim 7, wherein at least one of the first acoustic wave element and the second acoustic wave element is an acoustic wave element of a ladder type or a double mode type.

### Claim 11 (depends on 7)

The device according to claim 7, wherein at least any one of the input terminal and the output terminal of the first acoustic wave element and the second acoustic wave element is provided with a parallel arm resonator.

### Claim 12 (depends on 11)

The device according to claim 11, wherein a resonance frequency of the parallel arm resonator is lower than the first pass band.