Surface wave reflectors and resonators

The high-Q capability of acoustic surface-wave resonators in the hundred-megahertz frequency range along with their convenience of design and fabrication make such resonators attractive components for applications in oscillators and narrowband filters. The use of a transmission line model for the periodic array forming the reflector for the surface wave, along with a perturbation simplification, gives closed-form formulas which indicate the significance of the different parameters to be specified at fabrication. Besides the reflectors and the resonators themselves, consideration is given to the electrical coupling to the surface waves by means of interdigital transducers either external to the resonator or within the standing-wave pattern inside the resonator.