Design Of RF MEMS Tunable Filter Based On Coplanar Waveguide

In recent years,the microwave radio technology has experienced rapid development and profound changes.As an essential part of the RF transceiver,RF filter is greatly developing towards wider band,higher frequency,being portable and universal.Besides,the conventional filter can no longer fulfill the requirements of the cutting-edge communication technologies.In the recent ten years,the continuing improvement of the RF MEMS(Micro Electronic Mechanical Systems)technology has resulted in its introduction to the application of RF filter,which has not only improved the filters' RF performance in power consumption and band width,but also reduced the size and the weight of the filter,making it easy to integrate and revealing a fairly promising future in the application of many fields such as civil communication and satellite communication in space.Based on the theories of CPW transmission characteristics,microwave transmission network and traditional filter design theory,this essay mainly discusses the three following aspects:1.The essay is based on the design and application of the CPW filter.In the essay,it firstly designed and stimulated the defectively-structured unit cell and spirally-structured unit cell,analyzing its corresponding equivalent circuit model according to the property of the unit cell's RF performance.Then,based on the theory of EBG,the designs of stop-band Filter and dual Stop-band Filter are completed through the use of the periodic connection of many cells.Moreover,the equivalent circuit parameter model of stop-band filter is collected by analyzing the defective diagram structure with Schwarz transition and elliptic function.2.This essay is based on the design and application in tunable filter of RF MEMS.It studied the plan of the RF MEMS switch design and analyzed the mechanical performance as well as the electromagnetic property of MEMS switch;the application of MEMS switch to the design of tunable filter has transferred the filter into a well-functional tunable filter.At last,it designed an equivalent filter based on RF MEMS,which realizes the adjustable range within 20 percent and it has good RF performance.3.In this essay,the processing of RF MEMS tunable filter is realized.It carefully studied the technological techniques of MEMS and put forward a set of feasible technological techniques in RF MEMS tunable filter;meanwhile,the filter entity has been tested and the results have been analyzed.At last,it summarized the experience and lessons learnt from the processing experiment.