Investigating the impact of stuctural symmetry in coupled resonator arrays on the frequency stability of A CMOS-MEMS oscillator

Abstract

This paper presents experimental observations of the variations in short-term frequency stability in a low power CMOS-MEMS oscillator embedding two mechanically coupled double-ended tuning fork (DETF) resonators as a function of induced stiffness perturbations on the resonators. The Allan deviation of the 241 kHz output from the Pierce oscillator, based on a 0.35µm CMOS technology, is logged for various stiffness perturbations values applied on the two coupled resonators. The reported results show local optimum values of structural perturbations which yield to improved short-term frequency stability measures.