Tuning the bandwidth and center frequency of micromechanical acoustic resonators

As the radio frequency (RF) spectrum has become more crowded, the need for adaptable RF components, especially filters, has grown. Recently, aluminum nitride (AlN) microresonator filters have been reported. These filters/resonators are small (<1mm
³
), have the high quality factors (>1000) desired for steep filter roll-off, can achieve many filters covering a very wide frequency span (kHz to GHz) on a single chip and can be monolithically integrated with CMOS transistors for reconfiguring the filter array. Using AlN microresonator on CMOS technology, miniature, adaptable RF filters based on banks of switched filters have recently been reported.