SURFACE ACOUSTIC WAVE FILTER

摘要

A surface acoustic wave filter used for a frequency filter of mobile communication equipment such as a cellular phone and capable of providing stable filter characteristics even on receiving a large signal, characterized by comprising resonators (5 to 8) formed on a piezoelectric substrate (3), through holes (12) provided in the vicinity of the resonators (5 to 8) and a conductive material (13) filled in the through holes (12), the through holes (12) filled with the conductive material (13) being electrically grounded, wherein the through holes (12) disposed in the vicinity of the resonators (5 to 8) and filled with the conductive material (13) can release heat generated at the resonators (5 to 8) when a large signal is applied to an input terminal (1), thereby maintaining stable filter characteristics despite the application of a large signal.