介电层粗糙对电容式RF MEMS开关down态电容退化的影响

发布时间：2018-06-05 19:15

本文选题：RF + MEMS　；参考：《强激光与粒子束》2014年12期

【摘要】：电容式RF MEMS开关在控制高功率射频信号时会发生自锁失效,由于开关桥膜与介电层之间的粗糙接触,开关的down态电容会发生退化,因此很难建立开关自锁失效阈值功率的高保真预测模型。提出了3D电磁-等效电路仿真对比建模的方法。建立开关的3D电磁仿真模型,仿真得到具有任一表面粗糙度水平的介电层粗糙开关的隔离度(S21)曲线;再建立同一开关的等效电路模型,通过调谐其down态电容值,使得仿真得到的S21曲线与3D电磁模型仿真结果尽可能吻合;此时,可以确定一组根据开关3D电磁仿真模型设定的表面粗糙度水平与等效电路模型调谐好的down态电容值的关系;改变开关介电层的表面粗糙度水平,并重复上述步骤,确定了任一开关的介电层表面粗糙度与开关down态电容退化的关系。采用文献的down态电容实测数据,初步验证了该方法的可行性和合理性。并利用所得的开关down态电容随介电层表面粗糙度退化的特性,对简化的(介电层光滑)开关自锁失效阈值功率解析计算式进行了修订,可扩展用于预测介电层粗糙开关的功率容量。
[Abstract]:The capacitive RF MEMS switch will have self-locking failure when controlling the high power RF signal. Due to the rough contact between the bridge membrane and the dielectric layer, the down state capacitance of the switch will degenerate. Therefore, it is difficult to establish a high fidelity prediction model of self-locking failure threshold power. A method of 3D electromagnetic-equivalent circuit simulation and contrast modeling is presented. The 3D electromagnetic simulation model of the switch is established, and the isolating degree S21 curve of the dielectric layer rough switch with any surface roughness level is obtained, and the equivalent circuit model of the same switch is established, and its down state capacitance is tuned. The S21 curve is consistent with the simulation results of 3D electromagnetic model as much as possible. In this case, the relationship between the surface roughness level set according to the 3D electromagnetic simulation model and the tuned capacitance of the equivalent circuit model can be determined. By changing the surface roughness level of the dielectric layer and repeating the above steps, the relationship between the surface roughness of the dielectric layer of any switch and the capacitance degradation of the switching down state is determined. The feasibility and rationality of this method are preliminarily verified by using the measured data of down state capacitance in literature. Based on the characteristic that the down state capacitance of the switch degenerates with the surface roughness of the dielectric layer, the simplified analytical formula of the self-locking failure threshold power of the (dielectric layer smooth) switch is revised. It can be extended to predict the power capacity of the dielectric layer rough switch.
【作者单位】：西南科技大学信息工程学院;中国工程物理研究院电子工程研究所;重庆大学新型微纳器件与系统技术国防重点学科实验室;重庆大学光电技术及系统教育部重点实验室;
【基金】：中国工程物理研究院超精密加工技术重点实验室基金项目(ZZ14001,2012CJMZZ00009) 重庆大学光电技术及系统教育部重点实验室访问学者基金项目重庆大学新型微纳器件与系统技术国防重点学科实验室访问学者基金项目(2013MS04) 中国工程物理研究院电子工程研究所创新基金项目(S20141203) 西南科技大学研究生创新基金项目(14YCX107,14YCX109,14YCX111)
【分类号】：TM564

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