Large tuning range analog and multi-bit MEMS varactors

This paper presents a variety of analog and multi-bit RF MEMS varactors for use in tunable circuits and filters. Novel use of multiple pull-down electrodes covered with thick dielectrics allow for analog and digital-type control and long-hold down times. An analog varactor with nearly 7:1 usable tuning range and better than 80:1 switching range, a multi-state varactor-switch and a 4 bit capacitor bank are presented.