Patent ID: 9203376
Filing Date: 2015-12-01
Classification: H03H

Abstract:
1. A ladder-type surface acoustic wave filter assembly comprising: a substrate for receiving a plurality of components; an input terminal, an output terminal, and a ground terminal; a plurality of series resonators formed on the substrate and connected between the input terminal and the output terminal, the plurality of series resonators including a first series resonator and a second series resonator, the first series resonator having a lowest resonance frequency among the plurality of series resonators; a parallel resonator formed on the substrate and connected between the plurality of series resonators and the ground terminal; and a dielectric film coupled to and covering electrode fingers of each series resonator of the ladder-type surface acoustic wave filter assembly and having an inverse temperature coefficient of frequency to that of the substrate, a film thickness of the dielectric film in a region where the second series resonator is formed being smaller than a film thickness of the dielectric film in a region where the first series resonator is formed.