Characterization and Modeling of Continuously Tunable MEMS Varactor

In this work a circuit model for a continuously tunable varactor is presented which is based on a microelectromechanical system (MEMS). This behavioral model can be implemented in commercially available simulation tools and allows for complete circuit simulations in terms of small- and large-signal performance, as well as for transient and envelope responses. For the present implementation Agilent´s ADS is used but the modeling methodology can be generalized for use in other tools as well. For the MEMS varactor which is investigated in this paper good agreement is obtained between simulated and measured data. The capacitance variation for different tuning voltages as well as the frequency and power dependency of the component are discussed. For a bias voltage range up to 130 V a capacitance tuning ratio of more than 5:1 is obtained. The excellent linearity provided by minimal self actuation effects qualify the component for use in high power applications.