Piezoelectric substrate for surface acoustic wave device, and surface acoustic wave device

Abstract

An object of the invention is to achieve a wider passband and reduction in size of a surface acoustic wave device. The surface acoustic wave device comprises a piezoelectric substrate (1) and a pair of interdigitated electrodes (2) provided on one main surface of the piezoelectric substrate (1). As the material of the piezoelectric substrate (1), a single crystal belonging to the point group 32, having a crystal structure of Ca3Ga2Ge4O14 type, containing Ca, Nb, Ga, Si and O as main components, and being represented by the chemical formula Ca3NbGa3Si2O14 is used. The cut angle of the substrate (1) and the propagation direction can be selected as appropriate to thereby realize the substrate (1) which has a large electromechanical coupling coefficient that is effective to achieve a wider passband and a low SAW velocity that is effective to reduce the size of a surface acoustic wave device.

Dependencies are inferred from the claim text.