Coupled circuit and device simulations for design of RF MEMS VCOs

by Behera, Manas

A new coupled circuit and electrostatic/mechanical simulator (COSMO)

for the design of RF MEMS VCOs is presented in this thesis. The numerical

solution of device level equations is used to accurately compute the capacitance of

a MEMS capacitor. This coupled with a circuit simulator facilitates the simulation

of circuits incorporating MEMS capacitors. Different MEMS capacitor structures

are simulated and their effect on VCO performance is studied. In addition, the noise

from the MEMS capacitor is combined with a nonlinear circuit-level noise analysis

to determine the phase noise of RF MEMS VCO. Simulations of two different

MEMS VCO architectures show good agreement with experimentally observed

behavior.