Electric filter comprising a plurality of thin film bulk acoustic resonators
AssigneeTDK Corporation
InventorsRoger W. Whatmore, Paul B. Kirby, Qingxin Su, Eiju Komuro
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Abstract
An electric filter comprises a plurality of thin film bulk acoustic resonants (10, 11) arranged in series and in parallel which have electrodes (24, 25) of different working area (L) and optionally a piezoelectric layer (23) of different thickness (T).
Claims15
An electric filter comprising a plurality of thin film bulk acoustic resonators (FBARs) each comprising a thin layer of piezoelectric material sandwiched between a top electrode and a bottom electrode, the plurality of FBARs being linked in a series/parallel connection arrangement for which the areas of the electrodes in contact with the piezoelectric layer to form the resonators are different between in series and in parallel FBARs, wherein:
- all the FBARs are disposed on one substrate;
- the piezoelectric layer has a flat top surface;
- and
- the top electrode has a coplanar wave-guide structure by being disposed on the top surface of the piezoelectric layer together with two ground electrodes.
Dependencies are inferred from the claim text.