The design of efficient broadband wedge transducers

A simple coupled-mode theory has been developed for acoustic-surface-wave wedge transducers. Surface-wave transducers have been fabricated to operate on aluminum using water as the wedge material. The measured efficiency was 68% at 2.75 MHz, the theoretical value being 81%. Transducers have also been fabricated to operate on glass with a rubbery solid, RTV 615, as the wedge material. The experimental and theoretical efficiencies of this transducer at 3.2 MHz were 35 and 50%, respectively. The surface-wave leakage coefficient of RTV 615 on glass has been measured and found to be in excellent agreement with theory.