Reflecting trackchanger: new acoustic-surface-wave component for folding long delay lines onto small substrates

Abstract

A new acoustic-surface-wave component is described, which has the unique property of reflecting a freely propagating acoustic wave onto a path adjacent to the input path. This ‘trackchanging’ operation may be performed several times to fold a long acoustic-delay path onto a short substrate. The trackchanger has a loss below 3 dB over a 50% band-width, and is particularly suited to materials of large electro-mechanical-coupling constant. No external electrical components are required, and the device is constructed by standard photolithographic techniques.