Design and Simulation of RF-MEMS Tunable Capacitors Using Multiple Voltage Sources

A novel tunable RF-MEMS variable capacitor(varactor) is presented. The Flip -Flop structure of the design makes it possible to either increase or decrease the capacitance. Dimensions, sizes and the materials used in the device are chosen so that it can be manufactured in Urmia MEMS Lab. Silicon surface micromachining thechnology is used for the structure, which is CMOS compatible. Electrostatic actuation method is selected because of it's low power consumption so it can be used in low-power wireless applications. The value of the capacitor is changed by varying the gap between the two plates. Tuning voltage is in the range of 0-2 volts. The capacitor has the initial value of 0.43pF, maximum value of 0.92pF and minimum value of 0.3pF. Actuation and varactor plates are separate from each other. The structure is simple and can be fabricated by employing only 3 masks.