US 12,255,632 B2Granted

Acoustic wave device, and ladder filter including the same

AssigneeMurata Manufacturing Co., Ltd.

InventorKentaro Nakamura

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Abstract

An acoustic wave device includes a substrate including a piezoelectric layer, first and second resonators on the substrate, and a shared reflector. The second resonator is located on the substrate adjacent to the first resonator and has different frequency characteristics than the first resonator. The shared reflector is located on the substrate between the first resonator and the second resonator and is a reflector for both the first resonator and the second resonator. The first resonator includes a first interdigital transducer electrode with electrode fingers positioned with a first pitch. The second resonator includes a second interdigital transducer electrode with electrode fingers positioned with a second pitch. A lower limit frequency of a stop band of the shared reflector is between a lower limit frequency of a stop band of the first resonator and a lower limit frequency of a stop band of the second resonator. An upper limit frequency of the stop band of the shared reflector is between an upper limit frequency of the stop band of the first resonator and an upper limit frequency of the stop band of the second resonator.

Claims20

Dependent claims

An acoustic wave device comprising:

a substrate including a piezoelectric layer;
a first resonator on the substrate;
a second resonator on the substrate adjacent to the first resonator and having different frequency characteristics than the first resonator;
and
a shared reflector on the substrate between the first resonator and the second resonator and defining a reflector for both the first resonator and the second resonator;
wherein
the first resonator includes a first interdigital transducer electrode including electrode fingers positioned with a first pitch;
the second resonator includes a second interdigital transducer electrode including electrode fingers positioned with a second pitch;
a lower limit frequency of a stop band of the shared reflector is equal to both a lower limit frequency of a stop band of the first resonator and a lower limit frequency of a stop band of the second resonator, or between the lower limit frequency of the stop band of the first resonator and the lower limit frequency of the stop band of the second resonator;
and
an upper limit frequency of the stop band of the shared reflector is equal to both an upper limit frequency of the stop band of the first resonator and an upper limit frequency of the stop band of the second resonator, or between the upper limit frequency of the stop band of the first resonator and the upper limit frequency of the stop band of the second resonator.

8 more elements

An acoustic wave device comprising:

a substrate including a piezoelectric layer;
a first resonator on the substrate;
a second resonator on the substrate adjacent to the first resonator and having frequency characteristics different from frequency characteristics of the first resonator;
and
a shared reflector on the substrate between the first resonator and the second resonator and defining a reflector for both the first resonator and the second resonator;
wherein
the first resonator includes a first interdigital transducer electrode including electrode fingers positioned with a first pitch;
the second resonator includes a second interdigital transducer electrode including electrode fingers positioned with a second pitch;
and
where values obtained by multiplying a pitch of electrode fingers, a duty of the electrode fingers, and a thickness of the electrode fingers for the shared reflector, the first resonator, and the second resonator are respectively a first value, a second value, and a third value, the first value is the same as both the second value and the third value or between the second value and the third value.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/869,809Filed 21 Jul 2022 · continuation
Priority: JP 2020-01506731 Jan 2020
Published: US 2022/0360252 A110 Nov 2022
Granted: 18 Mar 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H03H 9/02574
Characteristics of substrate, e.g. cutting angles: of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical…
H03H 9/568
Electric coupling means therefor: consisting of a ladder configuration
H03H 9/02771
Grating lines having particular arrangements: reflector banks
H03H 9/02992
Of surface acoustic wave devices: details of bus bars, contact pads or other electrical connections for finger electrodes