Linear theory of the acoustoelectric oscillator

A linear 1-dimensional theory is given for the acoustoelectric oscillator. In this device, a direct current is passed through a plate of piezoelectric material sandwiched between two electrical contacts. Oscillations occur at frequencies near the natural acoustic frequencies of the plate when the `round-trip gain¿ exceeds unity. All five waves are included in the theory, and the effects of the external load on the growth rate and initial oscillation frequency are computed. The theory provides an explanation for such previously reported phenomena as mode enhancement and mode quenching.