Patent ID: 7183878
Filing Date: 2007-02-27
Classification: H03H

Abstract:
1. A surface acoustic wave filter comprising: a first dielectric layer having a first ground on its lower face and a plurality of transmission lines on its upper face; a second dielectric layer provided at the upper face of the first dielectric layer and having a second ground on its upper face; a surface acoustic wave element provided at the upper face of the second dielectric layer; and a cavity member provided at the upper face of the second dielectric layer and surrounding the surface acoustic wave element, wherein: one end of each of the plurality of transmission lines is connected to the surface acoustic wave element and the other end thereof is connected to the first or second ground; the surface acoustic wave filter has an additional transmission line between two neighboring transmission lines among the plurality of transmission lines; and the additional transmission line has multiple connections to the first or second ground at an interval equal to or lower than a wavelength of a using frequency.