Filters
AssigneeTDK Corporation
InventorsRoger W. Whatmore, Paul B. Kirby, Qingxin Su, Eiju Komuro
Life of this patent
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Abstract
An electric filter comprises a plurality of thin film bulk acoustic resonators (10, 11) arranged in series and in parallel which have different thicknesses (T) of one or more non-piezoelectric layers for example top electrode (24).
Claims30
An electric filter comprising a plurality of thin film bulk acoustic resonators (FBARs) linked in a series/parallel arrangement wherein each resonator is made up of a thin piezoelectric layer sandwiched between two metal electrodes and other layers of materials and in which the thicknesses of the non-piezoelectric layers in the FBAR resonators in the filter is varied one-from another.
An electric filter as described in any preceding claim, wherein the layer whose thickness is varied from one FBAR to another is the top electrode.
An electric filter as described in any preceding claim, wherein the piezoelectric material is zinc oxide.
An electric filter as described in any preceding claim, wherein the metal electrodes are substantially gold.
An electric filter as described in any preceding claim, wherein the variation in the thickness of one of the layers is produced by etching by excimer laser pulses.
An electric filter comprising at least one FBAR in series and at least one FBAR in parallel, each FBAR having a piezoelectric layer sandwiched between two electrodes wherein the thicknesses of one or more non-piezoelectric layers in the series FBAR is different to that in the parallel FBAR.
An electric filter according to any preceding claim comprising a plurality of FBARs linked in series and a plurality of FBARs linked in parallel.
An electric filter substantially as hereinbefore described with reference to the accompanying drawings.
Dependencies are inferred from the claim text.