EVALUATION OF THE INPUT ADMITTANCE OF SAW INTERDIGITAL TRANSDUCERS

Using the moment-method technique, the exact charge distribution on a finite interdigital array is obtained. Full account is taken of the coupling to bulk and surface modes. The moment-method technique greatly simplifies the evaluation of the transducer input admittance. The frequency dependence of the input admittance is computed for a different number of electrode pairs, different metallization ratio, and different sequences. The electrostatic capacitance is proved to be 28% higher than the zero-coupling capacitance for Y-Z lithium niobate.