Donald C. Malocha

High frequency SAW devices

This paper will discuss some of the technology approaches currently being pursued to extend the SAW device operating frequencies to the 1-6 GHz range. This range of frequencies has become commercially interesting in the past few years due to the large increase in wireless applications, especially cellular and mobile communications. This range of frequencies is challenging because it pushes the limits of the currently available technology implementations. In order to achieve the higher frequencies, research and development continues on the improvement of current SAW components and the development of new structures, examining new types of wave propagation, and exploring new materials.

Tap weight enhancement for broad-band filters

The theory for the replacement of a series of taps having small sbengths with a single larger tap while maintaining filter selectivity is presented. This technique works for the general class of bandpass fiiters, including broad-band fiiters with low shape factors, where withdrawal weighting is ineffective. This tap enhancement procedure increases tap weight accuracy and reduces diffraction distortions by removing small taps. Experimental results for capacity weighted transducers verify the theory.

Surface acoustic wave device fabrication.

Many frequency control operations for wireless and satellite communication systems are provided by acoustic solid‐state devices in the operating frequency range from 10 MHz to 3 GHz. Surface acoustic wave (SAW) device technology is a key technology because it is solid state, monolithic, high performance, and low cost. An important parameter is the versatility and simplicity in device fabrication since many techniques developed by the integrated circuit industry can be applied.

Surface acoustic wave technology and applications

Since the advent of the interdigital transduction for efficient transducer of surface acoustic waves (SAW), SAW devices have provided a key technology for communication and signal processing systems. In order to obtain the required electrical terminal characteristics, a diverse number of SAW components have evolved. Some of these components include bidirectional and unidirectional transducers, couplers, beam compressors, waveguides, and reflectors. The various SAW components are monolithically integrated, using processors similar to those for integrated circuits, on a piezoelectric substrate to produce dispersive filters, linear phase filters, resonators, convolvers, and correlators. These devices are manufactured for a wide variety of applications which include TV‐IF, cable TV, VCRs, fiber optic repeaters, radar, spread spectrum receivers, cellular radio, sensors, and a variety of communication receiver applications. The technological innovations and operation of the primary SAW components will be discus...