Transversely-excited film bulk acoustic resonator with interdigital transducer with varied mark and pitch

An acoustic resonator device comprising:

• a piezoelectric plate;
• and
• an interdigital transducer (IDT) comprising interleaved fingers on the piezoelectric plate,
• wherein the IDT transitions between a first pitch/mark combination and a second pitch/mark combination different from the first pitch/mark combination along a length of the IDT, and
• wherein a radio frequency signal applied to the IDT causes excitation of a same shear primary acoustic mode by both the first pitch/mark combination and the second pitch/mark combination, and wherein P1, M1, P2, and M2 are selected such that an amplitude of spurious modes is reduced as compared to a device having a same primary acoustic mode and a single pitch/mark combination.

An acoustic resonator device comprising:

• a piezoelectric plate;
• and
• an interdigital transducer (IDT) comprising interleaved fingers on the piezoelectric plate,
• wherein the IDT transitions between a first pitch/mark combination and a second pitch/mark different from the first pitch/mark combination across an aperture of the IDT, and
• wherein a radio frequency signal applied to the IDT causes excitation of a same shear primary acoustic mode by both the first pitch/mark combination and the second pitch/mark combination, and wherein P1, M1, P2, and M2 are selected such that an amplitude of spurious modes is reduced as compared to a device having a same primary acoustic mode and a single pitch/mark combination.