Design, construction, and testing of ultrasonic transducers with modified radial velocity profiles

In materials evaluation applications requiring the interrogation of modified far field patterns of an ultrasonic transducer, it is desirable to use a transducer which produces a beam with a Gaussian profile. A transducer with a velocity profile which is Gaussian as a function of radius and independent of angle is described. The transducer has been constructed by depositing a circularly symmetric metallic multiple electrode array on a 12. 7 mm diameter x-cut quartz disk. Each electrode is independently connected to an impedance network optimized to produce the Gaussian distribution with less than two percent maximum error. A computer aided electrode design and normalized three dimensional ultrasonic measurements of the far field distribution are presented.