Model of a voltage driven capacitive coupled micro electro-mechanical RF switch

摘要

A comprehensive and completely parameterised model is proposed to determine the related electrical and mechanical dynamic system response of a voltage driven capacitive coupled micro mechanical switch. An analytical approach is used throughout the modelling, providing representative coefficients in the set of two coupled time-dependent differential equations. The model also describes all the transferred energies, as e.g. the dissipated energy at the switch contacts and the re-feeded electrical power to the bias line. The determined switching dynamics is confirmed by experimental measurements, showing the validity of the model. The developed ohmic contact RF MEMS switch shows high isolation in the off-state > 12dB and low insertion loss of < 0.16dB in the on-state up to frequencies as high as 30GHz. The presented model is intended to be integrated into standard circuit simulation software, allowing circuit engineers to design the switch bias line, minimizing induced currents and contact bouncing, as well as to find the needed dimensions of the mechanical structure, for a desired switching time and actuation voltage wave-form. Moreover, process related design rules can be automatically verified.