US 12,316,304 B2
Vertically coupled SAW resonators
Stefan Ammann, Grosskarolinenfeld (DE); Matthias Pernpeintner, Grafing b. München (DE); Manuel Hofer, Graz (AT); and Stefan Leopold Hatzl, Kloech (AT)
Assigned to RF360 Singapore Pte. Ltd., Republic Plaza (SG)
Filed by RF360 SINGAPORE PTE. LTD., Republic Plaza (SG)
Filed on Dec. 21, 2022, as Appl. No. 18/069,958.
Prior Publication US 2024/0213958 A1, Jun. 27, 2024
Int. Cl. H03H 9/64 (2006.01); H03H 3/08 (2006.01); H03H 9/10 (2006.01); H03H 9/145 (2006.01); H03H 9/25 (2006.01)
CPC H03H 9/6483 (2013.01) [H03H 3/08 (2013.01); H03H 9/1092 (2013.01); H03H 9/145 (2013.01); H03H 9/25 (2013.01)] 30 Claims
OG exemplary drawing
 
1. A radio frequency (RF) filter, comprising:
a piezoelectric substrate having a first piezoelectric surface and a second piezoelectric surface opposite the first piezoelectric surface;
a first electroacoustic resonator comprising a first interdigital transducer (IDT) disposed over the first piezoelectric surface of the piezoelectric substrate;
a second electroacoustic resonator comprising a second IDT disposed over the second piezoelectric surface of the piezoelectric substrate; and
a silicon substrate, wherein the silicon substrate has a cavity formed in a portion of a surface of the silicon substrate,
wherein the second piezoelectric surface of the piezoelectric substrate shares a boundary with the surface of the silicon substrate, aligned such that the second IDT fits within the cavity without contacting the silicon substrate, and
wherein the second electroacoustic resonator is electrically coupled to the first electroacoustic resonator.