Influence of Capacitive Transducer Nonlinearities on the Amplitude Limiting of MEMS Based Oscillators


Microelectromechanical system (MEMS) based oscillators have become systems requiring high-performing references with minimal power consumption. The combination of higher quality factor and low parasitic capacitances allows them to out typical quartz crystal oscillators, capable of working at higher crucial for RF perform frequencies while providing excellent frequency stability with little power consumption. μ Previous work in [1] has demonstrated a 61 MHz oscillator meeting the GSM phase noise specification while consuming less than 80 W of power. More recent work in [2] demonstrates a 199 MHz oscillator, which is a much higher frequency than the limit for quartz crystal resonators, which is around 60 MHz.

The key enabler for scaling capacitive transducer MEMS up in frequency while consuming less power is reducing the electrode structure air gap, which drastically lowers the series motional resistance. As the transducer gap gets reduced further to improve performance of oscillators, it becomes more important to understand the nonlinearities which come with it. Lumped electrical models suffice performance of for small signal analysis, but fall short of oscillators reference to “tiny gap” resonators. predicting the This work aims to transducer nonlinearities of MEMS resonators, and the amplitude limiting of MEMS apply the analysis to based oscillators from crystal explain based ones. model the differences in 

Publication date: 
August 12, 2022
Publication type: 
Master's Thesis
Afshar, Sherwin. "Influence of Capacitive Transducer Nonlinearities on the Amplitude Limiting of MEMS Based Oscillators." (2022).