Patent ID: 9543924
Date: 2017-01-10
CPC Classifications: H01L,H03H

Claim:
1. A ladder surface acoustic wave filter comprising: an inductor: a series arm connecting an input terminal and an output terminal; at least one first parallel arm connecting the series arm and a ground terminal; at least one series arm resonator provided in the series arm; and at least two parallel arm resonators provided in at least one second parallel arm and connected to each other in series; wherein at least one connection point between the two parallel arm resonators connected to each other in series is grounded through the inductor; and the inductor is configured to shift a resonance point of resonation by the at least two parallel arm resonators of the at least one second parallel arm to a low frequency side and defines a sub-resonance point at a high frequency side relative to an anti-resonance point of the at least two parallel arm resonators of the at least one second parallel arm.