UHF SiGe push-pull VCO MEMS oscillators

Abstract

UHF quartz MEMS oscillators operating at 813 MHz, 920 MHz and 1.048 GHz carrier frequencies utilizing a push-pull topology based on MOSIS SiGe 7WL technology have been demonstrated. The 1048 MHz resonator has an unloaded Q of 6,920 and a motional resistance of 31.7 ohms, as measured in a vacuum. This yields an fxQ product of 7.25×1012, close to the expected limit for quartz devices of 1×1013. Device phase noise was measured showing a minimum phase noise of -100 dBc/Hz for an 813 MHz oscillator at 1 kHz offset. A tuning range of 80 ppm was demonstrated at 920 MHz.