Validation of PML-based models for the evaluation of anchor dissipation in MEMS resonators

Several barriers exist to the development and optimization of high frequency Micro-Electro-Mechanical (MEMS) resonators, primarily adequate control and understanding of dissipation phenomena. There is growing experimental evidence that anchor losses contribute significantly to damping. A reliable, large scale and native 3D numerical approach for estimating the anchor loss contribution in general is hence a much demanded tool. In this paper we discuss the implementation of a PML approach to simulate dissipation of waves radiated from the anchor into the substrate and provide several guidelines for a robust application to micro-structures. Next we employ the codes developed to perform extensive benchmarks against analytical solutions and verify the applicability of possible simplifications. In particular we show that the commonly adopted decoupling assumption between the resonator and the substrate might induce severe errors especially in 2D.