R.A. Waldron

Bio: R.A. Waldron is an academic researcher. The author has contributed to research in topics: Waveguide (acoustics). The author has an hindex of 1, co-authored 1 publications receiving 17 citations.

Microsound Components, Circuits, and Applications

Abstract: Surface acoustic wave components have been realized which perform the functions of transduction, amplification, and coupling. Applications are suggested which make use of these components. Exploratory work in connection with surface acoustic waveguides suggests the feasibility of acoustic analogs of conventional microwave transmission line (microsound) components on the surface of crystal and substrates. These microsound transmission lines, hybrids, and directional couplers interconnect microsound transducers, amplifiers, isolators, and phase shifters to form microsound circuits capable of autocorrelation, Fourier transformation, and cross correlation functions. Compatible component configurations are proposed and evaluated which perform these basic functions. The anticipated difficulties with their realization are discussed and the current status of critical problems including the epitaxial growth of thin films and submicron etching procedures will be given. Several circuits capable of performing correlation functions are given.

Elastic Surface Wave Guidance by (Δv/v) Effect Guidance Structures

Abstract: The possibility of utilizing guided surface acoustic waves in signal processing devices has generated interest in basic investigations of guidance mechanisms and structures for surface acoustic waves. Surface wave propagation, investigated in detail thus far in guidance structures, has unfortunately proven sufficiently dispersive to rule out many practical device applications. Reported here are theoretical investigations of the basic physical phenomena of a (Δv/v) guidance structure which is substantially nondispersive. Acoustic guidance in the (Δv/v) structure is assumed to be due principally to the velocity reduction Δv of a thin conducting strip on a piezoelectric substrate. With this assumption, major features of (Δv/v) guidance can be predicted theoretically from an isotropic nonpiezoelectric model which incorporates the velocity difference Δv. Numerical results are presented for quartz and lithium niobate. In addition, a generalized description for guided waves is developed which is approximately in...

High-Order Finite Elements for Inhomogeneous Acoustic Guiding Structures

Abstract: Silvester's high-order finite-element formulation for potential problems is extended to enable the analysis of acoustic wave propagation in lossless isotropic, uniform, and inhomogeneous guiding structures. The formulation allows a large class of problems to be solved using elements of any desired order, with only minimal computer coding. Three examples are cited---one involving a simple homogeneous region having an analytic solution, and two inhomogeneous problems. Good agreement with other methods and with limiting cases is obtained in each case.

Lenses and graded films for focusing and guiding acoustic surface waves

Abstract: Two novel schemes for guiding acoustic surface waves along curved paths on isotropic substrates are described. One involves the deposition of a slowing film of graded thickness along the intended path on a dielectric substrate. Paraxial-ray equations are developed to describe the ray paths adjacent to the axis of the guiding film, which are determined by the slowing factor resulting from a variable-thickness deposited film. Diffraction is taken into account through an approximation developed by Pierce for optical beams. It is shown that very thin films are sufficient for a substantial amount of directional control. The other guidance system employs a series of lenses in analogy with the lens guides developed for millimeter waves and optical beams. Some comments are made about thin-film lenses and the theory is developed for the focusing action of a lens formed by a spherical depression in (or protrusion from) the surface of a substrate. A simple analog for determining ray paths over generally nonplanar surfaces is described and applied to nonspherical depressions to evaluate their focusing properties.