Surface acoustic wave filter, duplexer, and communication device

摘要

A surface acoustic wave filter includes a piezoelectric substrate and first and second IDT provided thereon. The first IDT is formed on the surface of the piezoelectric substrate. The second IDT is formed on the surface of the piezoelectric substrate and positioned not in a straight line with the first IDT in the surface acoustic wave propagation direction. A first reflection edge is formed on the piezoelectric substrate, and positioned in a straight line with the first IDT in the surface acoustic wave propagation direction so that an SH type surface acoustic wave excited by the first IDT is input to the first reflection edge and is reflected therefrom at an angle to the input direction. A second reflection edge is formed on the piezoelectric substrate and positioned in a straight line with the second IDT in the surface acoustic wave propagation direction, so that the SH type surface acoustic wave reflected from the first reflection means is input to the second reflection edge and is reflected therefrom at an angle to the input direction, toward the second IDT.