Very high frequency channel-select MEMS filters based on self-coupled piezoelectric AlN contour-mode resonators

This paper reports experimental results on single-chip multi-frequency channel-select filters based on self-coupled piezoelectric aluminum nitride (AlN) contour-mode microelectromechanical (MEMS) resonators. Two-port AlN contour-mode resonators are connected in series and electrically coupled using their intrinsic capacitance to realize multi-frequency (94–271 MHz), narrow bandwidth (∼0.2%), low insertion loss (∼2.3 dB), high off-band rejection (∼60 dB) and high linearity (IIP3 ∼100 dBmV) channel-select filters on the same chip. This technology enables multi-frequency, high-performance and small-form-factor filter arrays and makes a single-chip multi-band reconfigurable radio frequency (RF) solution possible in the near future.