Design of Low Phase Noise UHF-Oscillator with Advanced SAW-Resonator-Technology

The design of a fixed frequency UHF oscillator stabilized by a surface acoustic wave (SAW-) resonator at 720 MHz is described. The resulting circuit yields excellent phase noise characteristics taking advantage of a new SAW-resonator structure as well as of computeroptimized dimensioning and sophisticated realisation. The requirements on long-term stability and tolerances determined by the resonator device are fulfilled using the SIEMENS SAW-technology and -processing. The circuit is temperature stabilized with an overall frequency drift of < ±10 ppm. The main application for oscillators with extremely low phase noise contribution is to serve as a reference source for LO-synthesizers in multilevel QAM radio relay systems.