Multi-frequency wideband RF filters using high electromechanical coupling laterally vibrating lithium niobate MEMS resonators

This paper reports on the first implementation of monolithically integrated wideband RF filters using Lithium Niobate (LN) based high electromechanical coupling (k_t²) MEMS resonators. MEMS-based RF filters operating at 500 and 750 MHz have been demonstrated on the same chip and shown a fractional bandwidth (FBW) of 2% and 3.9%, respectively - the highest demonstrated to date by laterally vibrating resonators (LVRs). The insertions loss (IL) of the 750 MHz filters is as low as 4 dB. The demonstration of these wideband filters is made possible by the design and fabrication of a two-port LN resonator topology that has lithographically defined center frequencies and exhibits k_t² as high as 10% and Q of 500 in air.