Piezoelectric resonator apparatus with acoustic reflector

摘要

A resonator apparatus has a piezoelectric resonator as well as an acoustic reflector which has a layer having a high acoustic impedance and a layer having a low acoustic impedance. The thickness of one layer is set different from a quarter of the wavelength in this layer at the operating frequency due to technological limitations in the manufacturing of this layer, and the thickness of the other layer is set dependent from the one layer, such that a predetermined minimum quality of the acoustic reflector is attained.