Cadmium sulphide evaporated-layer transducers

Techniques have been developed for the vacuum deposition of cadmium sulphide ultrasonic transducers for generating either longitudinal or linearly polarized shear waves over the frequency range from below 100 Mc to at least 1.8 Gc. These transducers are relatively quick and simple to make and are considerably more efficient and wider in bandwidth than those presently used in this frequency range. Conversion losses for one transducer as low as 6 dB have been obtained at 300 Mc rising to about 20 dB at 1.6 Gc. Discrimination against all unwanted modes of greater than 30 dB over a 30 percent bandwidth has been achieved.