Highly reliable analog MEMS varactors

In this paper we report experimental results on the capacitive range, stability and reliability of low-cost and high-performance analog MEMS varactors. Our varactors are contact-less, parallel-plate devices with a tuning range of nearly 3:1 and high maximum capacitance value of 272 fF. Total lack of ohmic and dielectric contacts considerably enhances the robustness of our proposed varactor, which does not require a hermetically sealed package and can be therefore produced at a very low cost. Reliability measurements of package-free varactors exposed to a regular laboratory environment for over three months are presented. Furthermore, non-linear effects for structures undergoing large deflections are experimentally addressed in this paper by demonstrating optimized varactors with nearly-ideal C - V curves.