Research On RF MEMS Tunable Filter Based On CPW And DGS Structure

With the rapid development of microwave communication technology, making electromagnetic wave frequency band to a higher development. Microwave filter is one of the most essential key devices in the microwave communication system, filter performance will directly affect the overall system performance. Currently using traditional CMOS processing technology to process microwave filter has high losses, low reliability and low RF performance and other shortcomings, limiting the further development of the system. However, because of the RF MEMS technology have low losses, broadband, high isolation, miniature size and light weight advantages, and easy to implement miniaturization and integration, so the RF MEMS technology become more and more widespread concerned.The RF MEMS tunable filter designed by CPW and DGS structures not only have good RF performance, but also can reduce the complexity, size, weight and power consumption of the system, and it has been extensively utilized in the RF front-end of new generation of microwave communication system.This paper mainly discus the RF MEMS tunable band-stop filters research analysis and design work. Firstly, the basic design theory of RF MEMS filter is introduced, primary study on the slow wave and band-stop characteristics of DGS structure, three new type DGS resonator structures are presented. LC, RLC, andⅡtype equivalent circuit model are given respectively, by electromagnetic simulation and circuit simulation of the DGS structure has been verified. Secondly, according to three new DGS structure resonance unit designed three not tunable filters, and analyzes the simulation result. Thirdly, the RF MEMS cantilever beam switch is used in II type with ear DGS band-stop filters, so the filter has tunable characteristics, a 7.47GHz scope RF MEMS tunable band-stop filter is presented. Finally, the MEMS processing technology and key process are introduced briefly, design a process flow of RF MEMS band-stop filter, which proposes a feasible direction for designing the RF MEMS tunable filter in the future.