Low impedance arrays of coupled Cross-Sectional Lamé mode resonators with high figure of merit in excess of 100

We report on novel high electromechanical coupling coefficient (k
_t
²
) and large input capacitance (C
₀
) Cross-Sectional Lamé mode resonators (CLMRs). We show that, by coupling multiple 3-fingers CLMRs, it is possible to simultaneously achieve high Figure of Merit (FoM, namely the product between quality factor, Q, and k
_t
²
) and large C
₀
-values. The use of this design approach permits to evade the intrinsic reduction of FoM, occurring in traditional single-plate CLMRs at increasing C
₀
-values. In addition, we report on the performance of a 3-finger 730 MHz CLMR, showing a FoM in excess of 147. Such a record high FoM is the highest reported in AlN resonators operating in the same frequency range.