Design And Simulation Of Electrostaticlly Actuated MEMS Microwave Switch

MEMS microwave switch is a new RF circuit component, which adopt MEMS technology. Comparing with traditional semiconductor switch, it has merit of low insertion loss, high isolation and good linearity. It will greatly affect radar and RF structure of communication system in existence to research on MEMS microwave switch.Since Petersen demonstrated micromechanics cantilever switch machined on silicon in 1979, many researchers have reported micromechanics switches, but research and development of MEMS component is limited in means and level of machining. MEMS technology is a front subject, which involves several research fields, many aspects of issues need to be researched, especially, the computer aided design (CAD) tool of the RF MEMS component. In the recent years, many high frequency MEMS switches have been excogitated, such as rotary switch, surface micromachining switch on GaAs substrate, capacitive membrane microwave switch and so on. Due to the problems of stability, switch time, servicing life, many MEMS switch also in research stage, has not been used in practice circuit largely.In this dissertation, several typical MEMS switches are analyzed. Aiming at the merit and shortage of these MEMS switches, and a switch of novel structure is demonstrated- MEMS membrane switch using torsion spring and leverage. This unique structure offers a new means to the present research and design of MEMS switch. Theoretical principle of its work is analyzed, and the feasibility of fabrication is also demonstrated. Electromechanical analysis and design, mode analysis of the switch structure and full wave magnetic field analysis is done, basing on these analysis results, the final the switch has been designed, dimension of machining is also given.The result of simulation shows that: (1) As it utilizes principle of torsion spring and leverage, the unique MEMS microwave switch has low actuation voltage < 10V. (2) Low insertion loss, less than 0.25 dB in 0 GHz -15 GHz; High isolation, greater than 20 dB in 8 GHz -13 GHz; Good stability, solving the problem of dielectric membrane easy to be punctured.