Patent ID: 7271685
Filing Date: 2007-09-18
Classification: H03H

Abstract:
1. A transversal surface acoustic wave filter comprising: a surface acoustic wave substrate; an input-side interdigital electrode disposed on the surface acoustic wave substrate; an output-side interdigital electrode disposed on the surface acoustic wave substrate so as to be spaced from the input-side interdigital electrode; and a shield electrode disposed on the surface acoustic wave substrate between the input-side interdigital electrode and the output-side interdigital electrode and connected to a ground potential; wherein a distance between an excitation point of the input-side interdigital electrode, which is closest to the shield electrode, and an intermediate point between the shield electrode-side end of the input-side interdigital electrode and the input-side interdigital electrode-side end of the shield electrode is in the range of about 0.8λ to about 0.975λ, where λ is a wavelength of a surface wave; and one of the input-side IDT electrode and the output-side IDT electrode is an unbalanced IDT electrode, and the other of the input-side IDT electrode and the output-side IDT electrode is a balanced IDT electrode.