US 12,255,626 B2
Solidly-mounted transversely-excited film bulk acoustic filters with excess piezoelectric material removed
Ventsislav Yantchev, Sofia (BG)
Assigned to MURATA MANUFACTURING CO., LTD., Nagaokakyo (JP)
Filed by MURATA MANUFACTURING CO., LTD, Kyoto (JP)
Filed on Dec. 27, 2021, as Appl. No. 17/563,033.
Application 17/563,033 is a continuation in part of application No. 17/123,029, filed on Dec. 15, 2020, granted, now 11,496,113.
Claims priority of provisional application 63/113,301, filed on Nov. 13, 2020.
Prior Publication US 2022/0158622 A1, May 19, 2022
Int. Cl. H03H 9/56 (2006.01); H03H 9/02 (2006.01)
CPC H03H 9/568 (2013.01) [H03H 9/02015 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A filter device, comprising:
a substrate;
a piezoelectric plate;
an acoustic Bragg reflector between the substrate and the piezoelectric plate; and
a conductor pattern on a surface of the piezoelectric plate, the conductor pattern comprising:
interdigital transducers (IDTs) of a plurality of resonators, and
a plurality of conductors that connect the plurality of resonators in a ladder filter circuit, the plurality of conductors comprising adjacent first and second conductors,
wherein the piezoelectric plate has a portion between the first and second conductors that is absent, and
wherein a width of the portion of the piezoelectric plate that is absent between the first and second conductors is greater than or equal to 50% of a distance between the first and second conductors.