# US 12,224,735 B2 · Diplexer using decoupled transversely-excited film bulk acoustic resonators

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- Number: US 12,224,735 B2
- Document ID: US12224735B2
- Status: Granted
- Kind: B2
- Application number: 17/542,284
- Filed: 2021-12-03
- Published: 2022-10-06
- Granted: 2025-02-11
- Earliest claimed: 2021-03-30
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Sean McHugh
- Web page: https://patentgrep.com/patent/US12224735B2

## CPC

- H03H 9/02228: {Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer}
- H03H 9/564: {implemented with thin-film techniques}
- H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles}
- H03H 9/02157: {Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness}
- H03H 9/13: for networks consisting of piezoelectric or electrostrictive materials (for networks using surface acoustic waves H03H9/145)
- H03H 9/171: {implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type}
- H03H 9/174: {Membranes}
- H03H 9/706: {Duplexers}
- H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence)
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

Diplexers, filter devices, and methods are disclosed. A diplexer includes a first chip comprising series resonators of a high band filter, a second chip comprising shunt resonators of the high band filter and series resonators of a low band filters, and a third chip comprising shunt resonators of the low band filter. The series resonators and the shunt resonators of the high band filter are decoupled transversely-excited film bulk acoustic resonators (DXBARs). The series resonators and the shunt resonators of the low band filter are transversely-excited film bulk acoustic resonators (XBARs).

## Claims

### Claim 1

A diplexer comprising:
a first chip comprising series resonators of a high band filter;
a second chip comprising shunt resonators of the high band filter and series resonators of a low band filters; and
a third chip comprising shunt resonators of the low band filter, wherein
the series resonators and the shunt resonators of the high band filter are decoupled transversely-excited film bulk acoustic resonators (DXBARs), and
the series resonators and the shunt resonators of the low band filter are transversely-excited film bulk acoustic resonators (XBARs).

### Claim 2 (depends on 1)

The diplexer of claim 1, wherein
the first chip comprises a first piezoelectric plate having a first thickness,
the second chip comprises a second piezoelectric plate having a second thickness greater than the first thickness, and
the third chip comprises a third piezoelectric plate having a third thickness greater than the second thickness.

### Claim 3 (depends on 2)

The diplexer of claim 2, wherein the first, second, and third piezoelectric plates are rotated Y-cut lithium niobate.

### Claim 4 (depends on 1)

The diplexer of claim 1, wherein each XBAR comprises:
a diaphragm formed by a portion of a piezoelectric plate spanning a cavity in a substrate; and
a conductor pattern comprising an interdigital transducer with interleaved fingers on the diaphragm.

### Claim 5 (depends on 1)

The diplexer of claim 1, wherein each DXBAR comprises:
a diaphragm formed by a portion of a piezoelectric plate spanning a cavity in a substrate;
a dielectric layer on the diaphragm; and
a conductor pattern comprising an interdigital transducer with interleaved fingers on the dielectric layer over the diaphragm.

### Claim 6 (depends on 1)

The diplexer of claim 1, wherein the first, second, and third chips are mounted on and electrically connected to an interposer, the interposer comprising:
conductors to connect the first, second and third chips; and
contacts for electrical connections to circuits external to the diplexer.

### Claim 7 (depends on 6)

The diplexer of claim 6, wherein the interposer comprises one of a printed circuit board, a low temperature co-fired ceramic circuit card, and a silicon chip.

### Claim 8 (depends on 6)

The diplexer of claim 6, wherein the conductors connect the series and shunt resonators of the high band filter in a first ladder filter circuit and connect the series and shunt resonators of the low band filter in a second ladder filter circuit.

### Claim 9 (depends on 1)

The diplexer of claim 1, wherein the high band is 5th Generation New Radio (5G NR) band n79 and the low band is 5G NR band n77.