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Ultrasonic Transducer Composed of Two Piezoelectric Layers with Variable Weighting

Two different piezoelectric layers with alternate vibrating polarity are stacked to compose wideband ultrasonic transducers. With this construction, the amplitude and the phase of applied voltage for individual piezoelectric layers can be adjusted so that we can provide variable weighting for the transducers to obtain a wideband vibrating mode. In this paper, the construction of the transducer is proposed and its theoretical analysis is described. Experimental results performed at a frequency around 4 MHz are further demonstrated with a comparison of the theory.