| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave filter which is a small size and has low loss and sharp attenuation characteristics. SOLUTION: The surface acoustic wave filter includes: one terminal pair surface acoustic wave resonator 1 which is a series arm resonator inserted between a signal input terminal IN and a signal output terminal OUT; one terminal pair surface acoustic wave resonators 2, 3 which are parallel arm resonators inserted between the signal input terminal IN and the signal output terminal OUT and a ground; and an inductance element 4 which is connected in parallel to the one terminal pair surface acoustic wave resonator 1. Electromechanical coupling coefficients of a piezoelectric substrate in which the one terminal pair surface acoustic wave resonators 1 to 3 are formed, are 0.1% or more and 1% or less. COPYRIGHT: (C)2011,JPO&INPIT |
