Rayleigh waves-a progress report

Abstract

In this paper we review the history of Rayleigh waves from their inception in 1885 to their manifold applications in modern radar and communications systems. It should be emphasized that while some of the modern applications represent convenient improvements over older technologies, in other cases surface acoustic wave (SAW) devices capability. In particular, the pulse compression radar lay dormant for many years, until the technology of SAW devices made it a practical proposition. Indeed even today SAW devices are employed in this application because the equivalent processing power at the receiver is not available from digital processors. In this review we neglected many current research topics involving SAW, for example those concerned with sensors, acousto-optics, and acoustic microscopy. Nevertheless we see that Rayleigh's investigations have led to developments of considerable practical importance, that could not reasonably have been foreseen in 1885, even by Lord Rayleigh. In addition we see that the implementation of SAW devices using interdigital transducers has considerable tutorial value. It is the author's experience that the operation of such devices provides students with real insight into such concepts as impulse responses, Fourier transforms, and convolution.