Uniform Serpentine Spring Design of THz MEMS Switch for a Low Driving Voltage

With the development of satellite communications, military radar and other fields, the demand for terahertz (0.1-10THz) tunable devices is growing, of which the switches are the most basic component, and Radio Frequency MEMS switches have a wider application in the high-frequency band due to their excellent RF performance of shorter transmission wavelength, higher operating frequency of the THz signal, and greater signal transmission loss. The electromagnetic waveguide must also be physically smaller as a result, which results in a high driving voltage. Therefore, to overcome the contradiction between RF loss and high driving voltage, a series contact RF MEMS switch structure with an operating frequency of 100-200GHz is reported in this study to realize the switching of the signal on/off state. The design achieves a low driving voltage of 23.17V with no collapse of the movable upper pole plate and automatic on/off switching by using a uniform serpentine to optimize the equivalent spring constant of the switch and COMSOL Multiphysics finite element simulation software to analyze the mechanical performance of the switch. The main indicators of the switch and the influence of S-parameters are analyzed and optimized using HFSS electromagnetic simulation software, resulting in a MEMS switch with insertion loss better than 0.83dB and isolation better than 19.88 dB.