Tunable bandpass filter using RF MEMS variable capacitors

The growing number of multi-standard and multi-application telecommunication systems has led to the development of new tunable filter topologies. Tunable filters are integral components in a variety of radar and modern multi-band communication systems [1]. The conventional tunable filters typically utilize YIG resonators, active resonators or varactors as the tuning element. However, these varactor based tuning filters have low Q values due to high series resistance of diodes. The development in microelectromechanical system (MEMS) technology allows new and innovative design of the tunable bandpass filters. In this paper, the concept in [4] is extended to design radio frequency (RF) MEMS tunable filters for wireless application.