Acoustic surface wave oscillator for use in portable telephone

摘要

The acoustic surface wave device includes a piezoelectric element (1) with an ionic implantation layer (11) which has been thermally treated, covering part of the surface. A comb type resonator electrode (12) is provided in on the ionic implantation layer. The structure comprises a first resonator and a second resonator, the first resonator having a frequency which is approximately equal to an anti-resonance frequency of the second resonator. Both resonators include the comb-type electrode. Specific conditions are laid down for the thickness of the ionic implantation layer w.r.t. the wavelength of the acoustic surface wave.