CPC H03H 9/568 (2013.01) [H03H 3/02 (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 9/02039 (2013.01); H03H 2003/023 (2013.01); H10N 30/877 (2023.02)] | 20 Claims |
1. A filter device, comprising:
a substrate;
a piezoelectric plate having front and back surfaces, the back surface on a surface of a substrate, portions of the piezoelectric plate forming one or more diaphragms, each diaphragm spanning a respective cavity in the substrate;
a conductor pattern on the front surface, the conductor pattern including a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators including a shunt resonator and a series resonator, interleaved fingers of each of the plurality of IDTs on a diaphragm of the one or more diaphragms;
a first dielectric layer having a first thickness on the front surface between the fingers of the IDT of the shunt resonator; and
a second dielectric layer having a second thickness on the front surface between the fingers of the IDT of the series resonator, wherein
the piezoelectric plate and all of the plurality of IDTs are configured such that radio frequency signals applied to the plurality of IDTs excite respective primary shear acoustic modes within the one or more diaphragms, and
the first thickness is greater than the second thickness.
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