Surface acoustic wave device, communication device using the same, and antenna duplexer

A surface acoustic wave device, comprising:

• a package having a coefficient of linear expansion;
• and
• two piezoelectric elements forming a surface acoustic wave element, and mounted on the package by a flip chip bonding, each of the two piezoelectric elements having different coefficients of linear expansion in a direction of propagation of surface acoustic waves generated by an interdigital electrode of the surface acoustic wave element and in a vertical direction thereto, and having a long side existing to a direction having a coefficient of linear expansion close to the coefficient of linear expansion of the package, and further having respective different central frequencies.

A communication device, comprising:

• a package having a coefficient of linear expansion;
• and
• a piezoelectric element forming a surface acoustic wave element, and mounted on the package by a flip chip bonding, the piezoelectric element having a surface acoustic wave filter having different coefficients of linear expansion in a direction of propagation of surface acoustic waves generated by an interdigital electrode of the surface acoustic wave element and in a vertical direction thereto, and having a long side existing to a direction having a coefficient of linear expansion close to the coefficient of linear expansion of the package.