| CPC H03H 9/568 (2013.01) [H03H 9/02015 (2013.01); H03H 9/02031 (2013.01); H03H 9/02062 (2013.01); H03H 9/02228 (2013.01); H03H 9/132 (2013.01); H03H 9/174 (2013.01); H03H 9/176 (2013.01); H03H 9/562 (2013.01); H03H 9/564 (2013.01); H03H 3/02 (2013.01); H03H 2003/023 (2013.01); H03H 9/02039 (2013.01); H10N 30/877 (2023.02)] | 17 Claims |

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1. A method of fabricating a filter device on a piezoelectric plate having front and back surfaces, the back surface attached to a substrate, the method comprising:
forming one or more cavities in the substrate such that respective portions of the piezoelectric plate form one or more diaphragms that are each over a respective cavity of the one or more cavities;
forming a conductor pattern on the piezoelectric plate, the conductor pattern including one or more interdigital transducers (IDTs) of a respective one or more resonators, wherein interleaved fingers of the one or more IDTs are on a respective diaphragm of the one or more diaphragms,
wherein the piezoelectric plate and the one or more IDTs are configured such that radio frequency signals applied to the one or more IDTs excite respective primary shear acoustic modes in the respective one or more diaphragms, wherein respective directions of acoustic energy flow of each of the excited primary shear acoustic modes are substantially normal to the front and back surfaces of the piezoelectric plate,
wherein the interleaved fingers of at least one IDT of the one or more IDTs extend parallel to each other and at an oblique angle to an Y crystalline axis of the piezoelectric plate, and
wherein the interleaved fingers of the at least one IDT are on a respective diaphragm of the one or more diaphragms extend at an angle different from the interleaved fingers of at least one other IDT of the IDTs that is disposed on a respective diaphragm of the plurality of diaphragms.
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