Abstract
Bridged MEMS-based micromechanical filters have been demonstrated that use a self-switching property of their de-biased capacitive transducers to achieve zero-loss on/off filter switching without the need for lossy series switches, and with settling times down to 1.5 μs. By dispensing with the need for series switches in the signal path, a small bank of 0.087% bandwidth, 9-MHz beam-based filters has achieved programmable channel/band selection with only 3 dB of insertion loss, comprised entirely of filter loss (i.e., no switch loss), with switching times 7x faster than the typical 10 μs of some of the fastest RF MEMS switches, and without the high actuation voltages (>90V) and reliability issues often associated with RF MEMS switches. Higher frequency 155-MHz disk resonators achieve even faster switching speeds, with settling times down to only 430 ns. Equipped with this self-switching property, capacitively transduced micromechanical resonators are attractive candidates for realization of the switchable filter banks targeted for future wireless transceivers. © 2005 IEEE.