LATERALLY COUPLED BAW FILTER EMPLOYING PHONIC CRYSTALS

摘要

An acoustic wave bandpass filter comprises at least two bulk acoustic wave resonators, laterally coupled to each other acoustically, each resonator including a film of piezoelectric material and at least a first electrode and/or a second electrode, said bulk waves propagating in a direction perpendicular to the plane of the film of piezoelectric material, characterized in that: it further comprises at least a first phononic crystal structure between said resonators such that the transmission coefficient of the lateral acoustic waves can be decreased in a direction parallel to the plane of the piezoelectric film; and the first phononic crystal structure is formed in a matrix of dielectric material or with patterns made from dielectric material.