US 11,838,006 B2
Acoustic wave device, band pass filter, duplexer, and multiplexer
Akira Michigami, Nagaokakyo (JP); and Katsuya Daimon, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Apr. 6, 2021, as Appl. No. 17/223,057.
Application 17/223,057 is a continuation of application No. PCT/JP2019/040884, filed on Oct. 17, 2019.
Claims priority of application No. 2018-196266 (JP), filed on Oct. 18, 2018.
Prior Publication US 2021/0226608 A1, Jul. 22, 2021
Int. Cl. H03H 9/56 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01); H03H 9/70 (2006.01)
CPC H03H 9/568 (2013.01) [H03H 9/13 (2013.01); H03H 9/17 (2013.01); H03H 9/70 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An acoustic wave device comprising:
a piezoelectric substrate including a piezoelectric layer made of lithium tantalate;
an IDT electrode on the piezoelectric substrate; and
a pair of reflectors on both sides of the IDT electrode on the piezoelectric substrate in an acoustic wave propagation direction; wherein
SH waves are used as a principal mode;
the IDT electrode includes a plurality of electrode fingers and the reflectors each include a plurality of electrode fingers;
when a length along a direction orthogonal or substantially orthogonal to a direction in which the plurality of electrode fingers extend is a width, each of the reflectors includes a first electrode finger and a second electrode finger having different widths;
four consecutive electrode fingers, which are any four of the plurality of electrode fingers of each of the reflectors, include both of the first electrode finger and the second electrode finger, and distances between centers of the four consecutive electrode fingers are equal or substantially equal; and
when an array of the four consecutive electrode fingers of each of the reflectors that include the first electrode finger and the second electrode finger is an array of a set of electrode fingers, the array of the set of electrode fingers of the each of reflectors is periodically positioned.