Surface acoustic wave devices using piezoelectric film on silicon carbide

An acoustic filter comprising:

• a first shunt resonator coupled to a ground potential
• a second shunt resonator coupled to the ground potential;
• and
• a series resonator coupled between the first shunt resonator and the second shunt resonator and to an input source, wherein the first shunt resonator, the second shunt resonator, and the series resonator each comprises:
• a piezoelectric thin film disposed on a carrier substrate, wherein the piezoelectric thin film is adapted to confine a fundamental shear horizontal (SH0) surface acoustic wave (SAW) within the piezoelectric thin film;
• an input bus line coupled to the input source;
• a ground bus line coupled to the ground potential;
• a first grating reflector disposed at a first end of the piezoelectric thin film and coupled between the input bus line and the ground bus line;
• a second grating reflector disposed at a second end of the piezoelectric thin film, the second end being opposite the first end, the second grating reflector being coupled between the input bus line and the ground bus line;
• and
• a plurality of interdigital transducers (IDTs) disposed between the first grating reflector and the second grating reflector, wherein each IDT comprises an input electrode and a ground electrode.

An apparatus comprising:

• a piezoelectric thin film disposed on a carrier substrate, wherein the piezoelectric thin film is adapted to propagate a fundamental shear horizontal (SH0) surface acoustic wave (SAW);
• a plurality of pairs of interdigital transducer (IDT) electrodes disposed on top of the piezoelectric thin film, wherein each pair of the plurality of pairs of IDT electrodes comprises a signal electrode and a ground electrode, wherein signal electrodes between adjacent pairs of the plurality of pairs of IDTs are separated by a first period;
• a first grating reflector disposed at a first end of the piezoelectric thin film and separated from a first end of the plurality of pairs of IDT electrodes, wherein the first grating reflector comprises a first set of electrically-shorted metal strips separated according to a second period;
• and
• a second grating reflector disposed at a second end of the piezoelectric thin film and separated from a second end of the plurality of pairs of IDT electrodes.