  In this paper it is shown how the equivalent circuit parameters of a MEMS
resonator can be simply obtained from an eigenfrequency simulation.
Additionally, it is demonstrated that the Q-factor as a result of support
losses in a MEMS resonator can be determined using a matched boundary layer.
The method is applied to calculate the frequency dependent admittance of a
diamond disk resonator. Results agree well with measurements and analytic
results. Comparison to a frequency response analysis establishes the validity
of the method and shows that it results in a large reduction of the simulation
time.
