减少静电漂移的高可靠RF MEMS开关研究

Research on anti-static and long-life high stability RF MEMS switch

RF MEMS开关具有制作工艺简单、易于集成等优点。而目前由电介质膜电荷积累造成的静电漂移及频繁机械碰撞导致严重的可靠性问题阻碍了其嵌入终端射频系统稳定性的提高。因此结构上采用电介质悬空薄膜改善电荷积累问题,并对开关机械结构限位实现开关的动态缓冲,降低高频次的机械碰撞损伤。同时依靠凸台触点结构,减少静电漂移。确立了电介质膜充电、开关寿命的理论模型并预测开关的寿命。结果表明,所设计开关寿命超过12900 h。相比已有RF MEMS开关,在两极板间距及金属梁-电介质膜间距分别相等的情况下,所提出的开关结构,寿命分别提高253倍和166倍,极大地改善静电漂移问题。在52.2 GHz工作频率下,隔离度为-41.31 dB,损耗为-0.25 dB,响应时间为50μs,为高性能、高可靠、长寿命射频开关提供了理论模型。

RF MEMS switches have the advantages of simple fabrication process and easy integration.However,the electrostatic drift and frequent mechanical collisions caused by the charge accumulation of dielectric film currently result in serious reliability problems that hinder the stability improvement of its embedded terminal RF system.Therefore,the structure of the dielectric suspension film is used to improve the charge accumulation problem,and the switch mechanical structure limit to realize the dynamic buffer of the switch to reduce the high-frequency mechanical collision damage.At the same time relying on the tab contact structure to reduce electrostatic drift.The theoretical models of dielectric film charging and switch life are established and the switch life is predicted.The results show that the designed switch life exceeds 12900 hours.Compared with the existing RF MEMS switches,the proposed switch structure improves the lifetimes by 253 and 166 times,respectively,and greatly improves the electrostatic drift problem when the bipolar plate spacing and the metal beam-dielectric film spacing are equal,respectively.The isolation of-41.31 dB,loss of-0.25 dB,and response time of 50μs at 52.2 GHz operating frequency provide a theoretical model for high-performance,high-reliability,and long-life RF switches.