Frequency Variable Oscillator Using a Monolithic SAW Phase Shifter

A new frequency variable oscillator with a monolithic SAW phase shifter is reported. A 214 MHz monolithic SAW phase shifter is fabricated on a silicon substrate with ZnO film. A voltage controlled phase shift is measured and discussed. An SAW oscillator is implemented with this phase shifter and its frequency is controlled by external voltage. A frequency shift of 120 kHz (a relative variation of 560 ppm) and excellent modulation characteristics are obtained without an external phase shifter.