Analysis and design aspects of SAW-delay-line-stabilized oscillators

The work reported here presents a simple model based on the common oscillator theory, developed by Dvornikov et al. (1983). It performs a linear analysis of a SAW delay-line-based oscillator and predicts its eigenfrequencies, the steepness excess and the power gain around the loop. The model allows an exact compensation of the electrical phase shift in the oscillator circuit through an acoustic path correction and optimization of the matching conditions between the active element and the interdigital transducers (IDT) of the SAW delay line in such manner that minimum loss and stable single mode operation are achieved. The model has been successfully tested in the design of SAW oscillators in the UHF-range using a simple broadband RC-amplifier. The final result is considerable simplification of the design process and improvement of the oscillator´s performance. The design procedure was successfully used in realizing stable SAW oscillators at 167, 200, 500, 630 and 750 MHz