Reactance filter comprising acoustic waves resonators

摘要

A reactance filter includes a series branch that includes a number of series impedance elements that are coupled in series and a number of parallel branches each having a parallel impedance element coupled to a respective node of the series branch. Each impedance element includes a resonator that works with acoustic waves. The resonators in the series branch include a first piezoelectric material and the resonators in the parallel branches include a second piezoelectric material that is different than the first piezoelectric material.

主权项

1. A reactance filter comprising:
a series branch within which a plurality of series impedance elements that are coupled in series; and a plurality of parallel branches each having a parallel impedance element, each parallel impedance element being coupled to a node that is coupled to a respective series impedance element, wherein each impedance element comprises a resonator that works with acoustic waves, wherein the resonators in the series branch comprise a first piezoelectric material, wherein the resonators in the parallel branches comprise a second piezoelectric material that is different than the first piezoelectric material, wherein the first piezoelectric material has a smaller coupling coefficient than the second piezoelectric material, and wherein a capacitance element is coupled parallel to at least one of the resonators in the series branch.