Single-chip multiple-frequency filters based on contour-mode aluminum nitride piezoelectric micromechanical resonators

This paper reports experimental results on a new class of single-chip multiple-frequency (up to 236 MHz) filters that are based on low motional resistance contour-mode aluminum nitride piezoelectric micromechanical resonators. For the first time, aluminum nitride rectangular plates and rings have been electrically cascaded to yield high performance, low insertion loss (as low as 4dB at 93 MHz) micromechanical band pass filters. This novel technology could revolutionize wireless communication systems by allowing the co-fabrication of multiple frequency filters (IF and RF) on the same chip, therefore reducing form factors and manufacturing costs. In addition, these filters require terminations on the order of kΩ, thereby making possible their direct interface with standard 50 Ω systems.