SURFACE ACOUSTIC WAVE DEVICE, COMMUNICATION EQUIPMENT USING THE SAME AND ANTENNA DUPLEXER

摘要

PURPOSE: To miniaturize a surface acoustic wave device where a piezoelectric element on which a surface acoustic wave element is formed is loaded on a package by flip chip bonding technology and to improve its reliability. CONSTITUTION: A package having a linear expansion coefficient and a piezoelectric element on which a surface acoustic wave element is formed and which is loaded on the package by flip chip bonding are installed. The piezoelectric element has the travel direction of a surface acoustic wave generated by the comb shaped electrode of the surface acoustic wave element and a direction whose linear expansion coefficient in a direction vertical to it differs and which has the linear expansion coefficient close to that of the package as long sides. The piezoelectric element is cut from single crystal having X, Y and Z crystal axes, and the X crystal axis is matched with the transmission direction of the surface acoustic wave.