Figure of Merit Enhancement of Laterally Vibrating RF-MEMS Resonators via Energy-Preserving Addendum Frame

Abstract

This paper examines a new technique to improve the figure of merit of laterally vibrating RF-MEMS resonators through an energy-preserving suspended addendum frame structure using finite element analysis. The proposed suspended addendum frame on the sides of the resonant plate helps as a mechanical vibration isolator from the supporting substrate. This enables the resonator to have a low acoustic energy loss, resulting in a higher quality factor. The simulated attenuation characteristics of the suspended addendum frame are up to an order of magnitude larger than those achieved with the conventional structure. Even though the deployed technique does not have a significant impact on increasing the effective electromechanical coupling coefficient, due to a gigantic improvement in the unloaded quality factor, from 4106 to 51,136, the resonator with the suspended frame achieved an 11-folds improvement in the figure of merit compared to that of the conventional resonator. Moreover, the insertion loss was improved from 5 dB down to a value as low as 0.7 dB. Furthermore, a method of suppressing spurious mode is demonstrated to remove the one incurred by the reflected waves due to the proposed energy-preserving structure.

Enhancement of The Quality Factor of Thin-Film-Piezoelectric-on-Si MEMS Resonator Using Phononic Crystals and Circular Suspended Frame Structure

“…The two PnC structures show lower transmission than the silicon bar, as shown in Figure 3(b). The transmission (S21) which defines the relation between the output-to-input port power transmission coefficients calculated by [37]:…”

“…As illustrated the resonator can be equivalently described as a damping mass-spring system. All the resonators can be represented as a system of a single mass by the equation [37]:…”

Reem-Shape Phononic Crystal for Q Anchor Enhancement of Thin-Film-Piezoelectric-on-Si MEMS Resonator

“…The shortcoming of this method is its inefficiency in reducing anchor loss. The other recently introduced method of improving the Q of the resonator is using energy-preserving suspended frames [ 17 ]. Even though it is reported to provide a significant improvement in Q , it introduces spurious modes near the intended resonance mode.…”

Reem-Shape Phononic Crystal for Q anchor enhancement of TPoS MEMS Resonator

“…The shortcoming of this method is not efficient in reducing anchor loss. The other recently introduced method of improving the Q of the resonator is using energy-preserving suspended frames 2 [17]. Even though it is reported to provide significant improvement in Q, it introduces spurious modes near the intended resonance mode.…”