电容式RF MEMS开关膜片边缘场效应的表征

Characterization on fringing field effect in capacitive RF MEMS Switch membrane

摘要:

计及电容式RF MEMS开关膜片上电场分布的边缘场效应后，很难建立高保真的开关自驱动失效阈值功率解析模型。因此，采用膜片承受射频信号功率的面积(ARF)和膜片与传输线的正对面积(A)的比值构建优值(FoM)，以表征膜片上电场分布的边缘场效应强弱。利用HFSS软件建立了开关自驱动失效的三维电磁模型；以一种常见的开关构型为案例，仿真得到了多种射频信号功率(Pin)和开关气隙高度(g0)条件下膜片边缘电场分布，并与优值计算结果进行了对比验证，初步证明了采用优值ARF/A表征膜片上电场分布的边缘场效应强度的可行性。

Abstract:

It is very difficult to establish high-fidelity model for self-actuation failure threshold power of switch when considering the fringing field effect of the electric field distribution of the capacitive RF MEMS(Radio-Frequency Micro-Electro-Mechanical System) switch membrane. Therefore, in order to characterize the intensity of the fringing field effect of the electric field distribution on the membrane, the Figure of Merit(FoM) is constructed by using the ratio between the area of the switch membrane subjected to RF power(ARF) and the facing area(A) (which is between the membrane and the transmission line). The three-dimensional electromagnetic model of self-actuation failure of the switch is constructed by using the HFSS(High Frequency Structure Simulator) software. For a case of a common configuration of the switch, the distribution of fringing electric field of membrane under a variety of RF signal powers (Pin) and with different air gaps of the switch(g0) are obtained through simulation. The comparison between the calculation of FoM and simulation results indicates that it is feasible to characterize the intensity of the fringing field effect of the electric field distribution of the membrane by using FoM(ARF/A).