US 12,224,736 B2
Alternative structure for realizing a transversal saw filter
Leland P. Solie, Chetek, WI (US); Jacqueline H. Hines, Annapolis, MD (US); and Andrew T. Hines, Annapolis, MD (US)
Assigned to SenSanna Incorporated, Hanover, MD (US)
Appl. No. 17/905,869
Filed by SenSanna Incorporated, Hanover, MD (US)
PCT Filed Mar. 10, 2021, PCT No. PCT/US2021/021784
§ 371(c)(1), (2) Date Sep. 8, 2022,
PCT Pub. No. WO2021/183696, PCT Pub. Date Sep. 16, 2021.
Claims priority of provisional application 62/987,651, filed on Mar. 10, 2020.
Prior Publication US 2023/0130157 A1, Apr. 27, 2023
Int. Cl. H03H 9/64 (2006.01); H03H 9/02 (2006.01); H03H 9/145 (2006.01)
CPC H03H 9/64 (2013.01) [H03H 9/02858 (2013.01); H03H 9/14547 (2013.01); H03H 9/14558 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A surface acoustic wave (SAW) device comprising:
a piezoelectric substrate;
at least one SAW element comprising an interdigital transducer (IDT);
said at least one IDT configured to launch acoustic waves onto said piezoelectric substrate as a combined wavefront that extends across an overall acoustic aperture;
wherein said overall acoustic aperture is divided spatially into a set of acoustic tracks parallel to the direction of acoustic wave propagation;
wherein the portion of the combined wavefront propagating in each acoustic track is a wavelet;
wherein the combination of all the wavelets propagating in each track comprises the overall wavefront; and
a stepped acoustic wave delay modification element, comprising:
multiple regions within the acoustic tracks;
wherein the multiple regions include two or more film regions in which a thin film of a material that will alter the SAW velocity is formed on the surface of said piezoelectric substrate; and
wherein lengths of the two or more film regions vary from track to track to create steps in the delay of the wavelets emerging from the acoustic tracks; and
wherein the combined wavefront comprising wavelets from all of the acoustic tracks emerging from said stepped acoustic wave delay modification element is spread out in time to implement a transversal filter impulse response function; and
at least one additional SAW element configured to interact with said combined wavefront across the entire aperture.