Multi-finger RF MEMS variable capacitors for RF applications

This paper presents a digital type RF MEMS variable capacitor with a tuning range on the order of 10:l. The digital tuning is obtained by having multiple beams suspended on a single pedestal. The typical actuation voltage is approximately 3 M O V but can be reduced to the 10-35V range with certain design modifications. The unloaded Q of the capacitor at 1 GHz in the up state is greater than 150, and as the Q can approach 90 in the down state.