Surface acoustic wave filter, apparatus, and electronic device

A surface acoustic wave filter, comprising:

• a support substrate;
• a first acoustic velocity layer, wherein a material of the first acoustic velocity layer is silicon dioxide;
• a second acoustic velocity layer disposed between the support substrate and the first acoustic velocity layer, wherein a material of the second acoustic velocity layer is aluminum nitride or silicon nitride, wherein a thickness of the second acoustic velocity layer is 30% λ to 50% λ, and wherein λ is a wavelength of the surface acoustic wave filter;
• a piezoelectric layer disposed on the first acoustic velocity layer, wherein Euler angles of a cut of the piezoelectric layer are (−5° to 5°, 81° to 83°, 85° to 95°);
• and
• an interdigital electrode disposed above the piezoelectric layer;
• wherein a longitudinal wave acoustic velocity in the first acoustic velocity layer is lower than a longitudinal wave acoustic velocity in the piezoelectric layer, and a longitudinal wave acoustic velocity in the second acoustic velocity layer is higher than the longitudinal wave acoustic velocity in the piezoelectric layer.

An electronic device, comprising:

• a transceiver configured to receive or send a signal, wherein the transceiver comprises a surface acoustic wave filter;
• and
• a processor configured to perform signal processing on the signal;
• wherein the transceiver is coupled to the processor;
• wherein the surface acoustic wave filter comprises:
• a support substrate;
• a first acoustic velocity layer disposed on the support substrate, wherein a material of the first acoustic velocity layer is silicon dioxide, wherein a thickness of the first acoustic velocity layer is 5% λ to 20% λ, and wherein λ is a wavelength of the surface acoustic wave filter;
• a piezoelectric layer disposed on the first acoustic velocity layer, wherein Euler angles of a cut of the piezoelectric layer are (−5° to 5°, 81° to 83°, 85° to 95°), and a longitudinal wave acoustic velocity in the piezoelectric layer is higher than a longitudinal wave acoustic velocity in the first acoustic velocity layer;
• and
• an interdigital electrode, wherein the interdigital electrode is disposed above the piezoelectric layer.