Surface acoustic wave device and communication apparatus using the same

摘要

A surface acoustic wave device includes first stage longitudinally coupled resonator type surface acoustic wave elements and second stage longitudinally coupled resonator type surface acoustic wave elements that are cascaded to each other and are arranged on a piezoelectric substrate. Each of the first and second stage longitudinally coupled resonator type surface acoustic wave elements is provided with at least three IDTs arranged along the direction of transmission of a surface acoustic wave. The central IDT of each of the longitudinally coupled resonator type surface acoustic wave elements includes narrow pitch electrode finger portions. At least one of the number and the pitch of the electrode fingers of the narrow pitch electrode finger portions of the first stage longitudinally coupled resonator type surface acoustic wave elements is set to be different from that of the second stage longitudinally coupled resonator type surface acoustic wave elements.