高隔离度阶跃结构MEMS开关的设计

Design of the High Isolation Step Structure MEMS Switch

针对MEMS开关提高电容比需要提高驱动电压的问题,提出了一种应用于Ku频段的阶跃结构MEMS开关,该结构结合了固支梁开关和悬臂梁开关,使得开关有两个驱动高度。当固支梁被吸合时,悬臂梁高度会随之降低,在增加开关电容比的同时降低了驱动电压。利用开关悬臂梁引入的电感,将开关闭合态LCd谐振点设计在14.5 GHz,使得开关在Ku频段的隔离度尤为优异。使用ANSYS和HFSS软件进行模拟,结果显示所设计开关驱动电压小于32 V,关态和开态电容比达到280,12～18 GHz的隔离度大于37 dB,插入损耗低于0.23 dB,回波损耗高于-17 dB。

The step structure MEMS switch at the Ku band was presented to solve the problem of increasing the pull-in voltage for high capacitance ratio of the MEMS switch. Combined the clamped beam switch and cantilever beam switch, the switch structure makes it have two drive heights. When the clamped beam was pulled-in, the height of the cantilever beam decreased, the pull-in voltage decreased while the switch capacitance ratio increased. Using the inductance resulted by the switch cantilever beam, the resonance point of the switch closed state LCa was designed at 14. 5 GHz, making the isolation of the switch at Ku-band extremely outstanding. The simulation was conducted by the ANSYS and HFSS software. The results show that the pull-in voltage is lower than 32 V, the capacitance ratio between down state and up state reaches 280,the isolation is more than 37 dB, the insertion loss is less than 0.23 dB and the return loss is higher than - 17 dB at 12- 18 GHz.