US 12,271,774 B2
Composite substrates for saw tags or RFID and sensors applications
Sylvain Ballandras, Besançon (FR); and Thierry LaRoche, Besançon (FR)
Assigned to Soitec, Bernin (FR)
Appl. No. 16/980,324
Filed by Soitec, Bernin (FR)
PCT Filed Mar. 14, 2019, PCT No. PCT/EP2019/056428
§ 371(c)(1), (2) Date Sep. 11, 2020,
PCT Pub. No. WO2019/175315, PCT Pub. Date Sep. 19, 2019.
Prior Publication US 2021/0034935 A1, Feb. 4, 2021
Int. Cl. H03H 9/02 (2006.01); G06K 19/067 (2006.01); H03H 3/08 (2006.01); H03H 9/25 (2006.01)
CPC G06K 19/0675 (2013.01) [H03H 3/08 (2013.01); H03H 9/02559 (2013.01); H03H 9/02574 (2013.01); H03H 9/25 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A surface acoustic wave tag device, comprising:
an acoustic wave propagating substrate comprising a composite substrate including a base substrate and a piezoelectric layer;
at least one transducer structure comprising inter-digitated comb electrodes disposed over the acoustic wave propagating substrate; and
a set of reflectors positioned at various delays on one side of the transducer structure in the direction of propagation of an acoustic wave having a wavelength, each reflector comprising a different number of metallic strips, and wherein the metallic strips of each reflector are connected to each other and shorted;
wherein a crystallographic orientation of the piezoelectric layer with respect to the base substrate is such that the propagation of a shear wave inside the piezoelectric layer and in the direction of propagation corresponding to the acoustic wave is enabled; and
wherein a thickness of the piezoelectric layer is smaller than the wavelength.