Research On Key Technology Of RF MEMS Switch Designing And Fabricating For 5G Communication Applications

RF MEMS switch,as a key electronic device,could control conduction and disconnect of signal in the Micro-electromechanical Systems(MEMS).Because of its small size,low power consumption,low cost and high reliability,RF MEMS switch could be widely used in all kinds of communication systems of radio frequency,microwave and millimeter wave.The paper proposes a straight-plate-type RF MEMS switch and studies performance from the aspects of constructional design,simulation optimization and fabrication process.By breaking through the key technologies,such as RF MEMS switch design and fabrication,the defects of traditional switches were remedied and the advantageous performance was achieved,for instance,low actuation voltage,low insertion loss,high isolation,small volume and others.Furthermore,the series contact RF MEMS switch with these performance could applied for 5G communication applications.Firstly,the overall structure design and optimization of RF MEMS switches are studied.The effects of the switch geometrical parameters on the actuation voltage are analyzed by using the statics methods.The influence of the parameters of the switch on its RF performance is determined by using the equivalent circuit model of the switch.The structural parameters of the top electrode were obtained by modeling,simulating and optimizing some geometric dimensions of the switch with HFSS software.In addition,the stress of the top electrode is simulated by Comsol software to restrain the switch from serious warping under the actuation voltage.Finally,the switch structures,such as top electrode of straight-plate-type and lower electrode of gradual-change-type,have ideal mechanical and electrical simulation performance.The paper introduces the fabrication process of the designed switch,the rules of layout design and lists the layout,and the detailed processing steps and important process parameters,simultaneously expounds the deposition,lithography,etch and other process operations.The sample of RF MEMS switch is obtained and fabricated through these process.It is found that the electrode of the sample is relatively smooth,on account of fully releasing of the sacrifice layer so that there is no warpage and adhesion phenomenon.In this paper,the performance test method of RF MEMS switch sample is also presented,and the performance of the developed switch sample is tested and analyzed.The test results show that the actuation voltage of the switch is 9.9 V and the response speed is fast,about 4.215 ?s.In the operating frequency of DC~6GHz,the switch has good microwave performance,such as the insertion loss is less than 1.23 dB,the isolation is more than 35.27 dB,the return loss is more than 33.99 dB,and the standing wave ratio is less than 1.14.A kind of RF MEMS switch with low actuation voltage,fast response,low insertion loss and high isolation is realized through the research in this paper,which lays a foundation for the application of 5G communication in our country.