Equivalent electrical circuits of interdigital transducers for piezoelectric generation and detection of Rayleigh waves

Experimental and theoretical studies of the generation and detection of Rayleigh waves by arrays of interdigital electrodes deposited on piezoelectric ceramics are described. Experiments with transient voltages suggest that such a transducer can be represented by a 1-dimensional equivalent electrical circuit based on that conventionally used for a bulk-wave transducer, incorporating tranmission lines and piezoelectric transformers. More detailed studies lead to the adoption of a model in which each electrode is represented by the ciruit of a bulk-wave transducer of width one-third of the spatial period of the array. This circuit is used in studies of three important characteristics: the continuous-wave radiation resistance of an array, the continuous-wave voltage transfer from a generating array to a detecting array, and the detector waveform resulting from a transient generating voltage. The circuit is shown to be capable of dealing simultaneously with all three situations more accurately than circuits previously proposed.