CPC H03H 9/02228 (2013.01) [H03H 3/02 (2013.01); H03H 9/02031 (2013.01); H03H 9/174 (2013.01); H03H 9/176 (2013.01); H03H 9/562 (2013.01); H03H 9/564 (2013.01); H03H 9/568 (2013.01); H03H 2003/023 (2013.01)] | 19 Claims |
1. A filter device comprising:
at least one piezoelectric layer attached directly or via one or more intermediate layers to a substrate of a resonator of the filter device, portions of the at least one piezoelectric layer forming one or more diaphragms spanning respective cavities of the filter device;
a conductor pattern at the at least one piezoelectric layer and including a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators, interleaved fingers of each of the plurality of IDTs on one of the one or more diaphragms of the at least one piezoelectric layer; and
an insulating layer disposed between the at least one piezoelectric layer and portions of the conductor pattern other than the interleaved fingers,
wherein the insulating layer is not disposed on the diaphragm one or more diaphragms.
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