Observations on Non-Linearities in SAW Devices Employing Narrow-Aperture Slanted Chirp Transducers

Abstract

Acoustic non-linearities can be observed when narrow-aperture high frequency surface acoustic wave devices are operated at high power levels. Previous investigations into this topic have mainly been concerned with the generation of harmonic frequencies from a single input tone. The present paper extends this work in two respects. Firstly, it describes an experimental and theoretical investigation into a problem of considerable practical interest, namely the generation of third-order intermodulation products in the presence of two (or more) input frequencies. The second topic of this paper is a description of a two-dimensional SAW structure (employing slanted chirp tranducers) in which such intermodulation effects are minimised by causing different frequency components to traverse physically distinct paths. Some possible applications of such devices are described.