RESUMO
An efficient technique is presented for 3-D finite element modeling of large-scale periodic excited bulk acoustic resonator (XBAR) resonators in the time-harmonic domain. In this technique, a domain decomposition scheme is used to decompose the computational domain into many small subdomains whose FE subsystems can be factorized with a direct sparse solver at a low cost. Transmission conditions (TCs) are enforced to interconnect adjacent subdomains, and a global interface system is formulated and solved iteratively. To accelerate the convergence, a second-order TC (SOTC) is designed to make the subdomain interfaces transparent for propagating and evanescent waves. An effective forward-backward preconditioner is constructed that when combined with the SOTC significantly reduce the number of iterations at no additional cost. Numerical results are given to demonstrate the accuracy, efficiency, and capability of the proposed algorithm.
Assuntos
Algoritmos , Simulação por Computador , Análise de Elementos FinitosRESUMO
Application of the finite-element method (FEM) for the simulation of surface acoustic wave (SAW) devices has been constrained by the large number of degrees of freedom required, resulting in large memory usage and long computation times. We propose a new 2-D algorithm that takes advantage of the periodic structure typical of SAW devices. The device is partitioned into small, repeatedly occurring building blocks. Only unique building blocks are simulated with FEM. The device geometry is presented as a hierarchical tree of cascading operations, where smaller blocks are combined into larger blocks. This is equivalent to the full FEM simulation of the device, implying the drastic reduction of memory consumption and simulation time for structures with a high degree of periodicity. The method is verified against FEM/BEM-based software. To ensure accurate and efficient simulation, the boundary conditions should be chosen according to the anisotropy of the substrate crystal.
