2008-092017 is referenced by 9 patents.
PROBLEM TO BE SOLVED: To obtain an SAW filter having a high Q, a low insertion loss, and high damage resistance to an electrode, and also to provide an SAW resonator.SOLUTION: In the SAW filter, a plurality of crossed electrode fingers arranged in the propagation direction of surface acoustic waves and interdigital electrodes having bus bars for connecting the crossed electrode fingers, oppose each other, and an IDT, where the crossed electrode fingers cross each other, is provided on a piezoelectric substrate. The IDT branches has not less than one branching electrode finger. The branching electrode finger branches from the crossed electrode fingers, is positioned in the non-cross section between a cross section at which the crossed electrode fingers cross each other and the bus bar, and includes a branching electrode finger body section extended in a direction nearly orthogonally crossing the propagation direction of the elastic surface waves. The SAW filter can be applied to any of a longitudinally coupled multiple mode type filter, a ladder type filter, a resonator, a filter in which the resonator is connected to the longitudinally coupled multiple mode type filter in series, and the like.