Patent ID: 11901873
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. An acoustic resonator device comprising:
a substrate;
a piezoelectric layer attached to the substrate;
an interdigital transducer (IDT) on a surface of the piezoelectric layer and including interleaved fingers, the IDT being configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the piezoelectric layer;
a back-side partial Bragg reflector on a back surface of the piezoelectric layer, the back-side partial Bragg reflector including of a layer of low acoustic impedance dielectric material on the back surface of the piezoelectric layer and a layer of high acoustic impedance dielectric material on the layer of low acoustic impedance dielectric material and opposite the piezoelectric layer; and
a front-side partial Bragg reflector on a front surface of the piezoelectric layer, with the front surface of the piezoelectric layer opposing the back surface of the piezoelectric layer, the front-side partial Bragg reflector including of a layer of low acoustic impedance dielectric material on the front surface of the piezoelectric layer and a layer of high acoustic impedance dielectric material on the layer of low acoustic impedance dielectric material and opposite the piezoelectric layer,
wherein each of the back-side partial Bragg reflector and the front-side partial Bragg reflector is configured such that the respective reflectors do not reflect at least a portion of energy of an incident acoustic wave when the primary shear acoustic mode is excited in the piezoelectric layer, and
wherein the primary shear acoustic mode is a bulk shear mode where acoustic energy propagates along a direction substantially orthogonal to the surface of the piezoelectric layer and transverse to a direction of electric field created by the IDT.