Resonant Inc.
BANDPASS FILTERS USING TRANSVERSELY-EXCITED FILM BULK ACOUSTIC RESONATORS

Abstract:

Bandpass filters for a target communications band extending between a lower band edge and an upper band edge are disclosed. A bandpass filter includes one or more shunt resonators and one or more series resonators connected in a ladder filter circuit, wherein a relative difference between the anti-resonance and resonance frequencies of each acoustic resonator is greater than a fractional bandwidth of the target communications band. A first capacitor is connected in parallel with a first shunt resonator from the one or more shunt resonators, and a second capacitor connected in parallel with a first series resonator from the one or more series resonators.