Patent ID: 8098118
Filing Date: 2012-01-17
Classification: H01P,H03H,Y10T

Abstract:
1. A bandpass filter comprising: a bulk acoustic wave (BAW) filter composed of a plurality of piezoelectric resonators connected in a ladder configuration between a first signal transmission path and a ground to provide a specific frequency bandpass, each piezoelectric resonator comprising a piezo-electric element disposed between a lower electrode and an upper electrode; a patterned planar filter being configured to attenuate frequencies near and outside of said bandpass, said planar filter comprising a strip line structure composed of a ground conductor, a dielectric layer on said ground conductor, and a strip line formed on said dielectric layer to define a second signal transmission path, wherein said strip line being added with at least one stub composed of a loading segment extending in a spaced relation from said strip line, and a tap segment extending from said strip line and merging at an intermediate portion of said loading segment between opposite lengthwise ends thereof, and said BAW filter and said planer filter are formed on a common substrate with said first and second signal transmission paths connected to each other.