Surface acoustic wave devices: a rewarding past, a significant present, and a promising future

The concept of a thin-film metal interleaved comb structure (interdigital transducer) on a polished piezoelectric plate, was first introduced in 1965 as an efficient means for the generation and detection of surface acoustic waves. There followed a wealth of ideas and a flurry of developments which produced frequency and time domain devices significantly enhancing the signal processing capabilities of microwave systems. These devices, many of which were first implemented in military radar and communication systems, covered a frequency range from 10 MHz to well over 1.0 GHz. Today, the diversity of SAW device applications in electronic products, the number of manufacturers, the total number of devices manufactured, and the employees worldwide involved in the design, development, and manufacture of SAW devices, speaks of a very robust technology with a promising future. This paper reviews the basic piezoelectric substrate based device concepts, characterize present activities, and take a look at where SAW technology is headed in the near future.