Analysis of the natural single phase unidirectional SAW transducer

The calculation of fundamental parameters needed for the analysis of a natural single-phase unidirectional transducer (NSPUDT) is reported. Analytical forms for the NSPUDT parameters on arbitrary crystal cuts are given in terms of material constants and electrode geometry. The acoustic-wave velocity, electromechanical-coupling parameter, power-flow angle, static capacitance, transduction coefficient, and reflection from a single strip due to both electrical and mechanical perturbations are found as a function of the propagation angle on ST quartz. The coupling-of-nodes (COM) theory is then used to analyze a practical NSPUDT device. From solutions of the coupled mode equations, the characteristics of radiation admittance and insertion loss are found. The COM-model is verified by comparison with measurements of a device built on an unconventional orientation on ST quartz