Nonlinear UHF quartz MEMS oscillator with phase noise reduction

Stable local oscillators with low phase noise are extremely important elements in high performance communication and navigation systems. We present the development of compact UHF-band frequency sources capable of maintaining low phase noise for handheld portable systems. We also explored nonlinearity in MEMS resonators and attempted to use nonlinear dynamics to enhance phase noise performance. Using the quartz MEMS technology, we have thus far demonstrated a 635 MHz oscillator with -112 dBc/Hz phase noise at 1 kHz offset frequency. The controlled oscillation of this nonlinear Duffing resonator in a closed-loop system with improved phase noise is described.