N-port network for the electromagnetic modeling of mems switches

Abstract

with Battle-Lemarie scaling functions, 6 th -and 10 th -order centered differences are very close to the accuracy limit. It agrees with the theoretical evaluation.Therefore, the 6 th -order accurate method can sufficiently eliminate the numerical-dispersion error of the ADI-FDTD method, which is caused by approximating the spatial derivatives using the finite-difference method. CONCLUSIONSIn this paper, we have developed a high-order ADI-FDTD method by approximating the spatial derivatives of the ADI-FDTD method with Battle-Lemarie scaling functions and high-order centered differences. It has been proved that the method is unconditionally stable. The numerical dispersion of the high-order ADI-FDTD method with different schemes and the accuracy limit of the ADI-FDTD method for a given time-step size have been derived. It was found that the numerical dispersion is improved. In addition, it was observed that the numerical-dispersion error is very close to the accuracy limit at any mesh density when the 6 th -order centered difference is applied. ACKNOWLEDGMENTThe work described in this paper was fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China, under project no. PolyU 5131/01E. (and the references therein), this task is very challenging because MEMS exhibit generally complex geometries and critical "aspectratios". The accurate design of such circuits requires electromagnetic simulations that combines full-wave analysis (for the description of the distributed passive part of the circuits) with equivalentcircuit models (for lumped passive and active devices) [5]. Because their dimensions are much smaller than the wavelength, a MEMS switch is usually modeled by a shunt CLR lumped-element circuit derived from quasi-static analysis. However, the incorporation of such a lumped element in an electromagnetic simulator based on a spatial discretization may create an ambiguity due to the distribution of this model over the mesh [6]. An alternative electromagnetic analysis consists of applying a direct full-wave method to the overall MEMS circuit (see, for example, [7,8] for modeling of air-bridges in coplanar waveguide). But these methods are based on the spatial discretization of the whole circuit (MEMS switches included) and, consequently, require a large computer storage capability and are time-consuming as the number of switches increases. Moreover, the wide diversity of scales in MEMS circuits may generate ill-conditioned matrices in the computation of the boundary value problem.Combining the advantages of different numerical techniques' hybrid approaches has provided encouraging results for MEMS electromagnetic modeling [9]. In this paper, we propose an alternative approach named the multi-scale integral-equation (MS-IE) method. The first version of this technique has been reported recently for the modeling of planar active antennas [10,11]. An extension of this precursor is proposed here for the analysis of RF-MEMS. A coplanar-waveguide shunt MEMS switch-...

A review of micro-contact physics, materials, and failure mechanisms in direct-contact RF MEMS switches

“…Analyzing the performance and characteristics of the switch requires a close coupling of the mechanical domain, with the electromagnetic domain. For electromagnetic analysis, a MEMS switch is usually modeled as a CLR lumped-element circuit with the relevant active and passive elements derived from quasi-static analysis [24].…”