| RF MEMS switch is one of the key devices used in the field of wireless communication to control electromagnetic wave transmission.It has the characteristics of low loss,small size,low cost,and high reliability.It can be combined with MEMS filters,MEMS antennas,MEMS attenuators,MEMS phase shifters,etc.to form tunable radio frequency MEMS devices,which can realize multifunctional applications while reducing the size of the device.Multiple MEMS switches can also be used to integrate matrix switches to achieve simultaneous transmission of multi-channel signals and enhance information transmission capabilities.This paper presents the design of RF MEMS single-pole multi-throw switches,mainly researching common single-pole double-throw switches and single-pole four-throw switches.Through coplanar waveguide design,power divider design,electrode design,and microwave performance simulation,the structure design of single-pole double-throw switches and single-pole four-throw switches is completed.Through the design and processing of single-pole double-throw switches,the feasibility of the design scheme was verified,and finally the single-pole double-throw switch prototype was tested to verify the feasibility of the design and processing flow.The aim is to obtain a research method for the structural design and processing flow of a reliable single-pole multi-throw switch.The thesis first conducts a simple research on the radio frequency MEMS switch,and designs a single-pole multi-throw switch by comparing and selecting an electrostatic-driven series contact structure.After analyzing the key structure of the switch,through research on the selection and design of coplanar waveguide materials,the design and optimization of power dividers,and the selection and optimization of electrode structure materials,the design of the switch structure of RF MEMS single-pole double-throw and single-pole four-throw is completed.Then use the microwave simulation software HFSS to simulate the performance of the design structure.On the basis of the design,the paper taped out the designed single-pole double-throw switch.By understanding the design principles of the layout,the layout design of the single-pole double-throw switch for MEMS technology is completed.Then,the processing flow and related process parameters are introduced in detail,and the low-roughness electroplating technology used in processing is focused on research.Through the MEMS process,the prototype of the radio frequency MEMS single-pole double-throw switch is obtained.At the end of the thesis,the test of the RF MEMS single-pole double-throw switch was tested.Mainly carry out the test of radio frequency performance and switch design of radio frequency MEMS single pole double throw switch.The radio frequency performance of main concern is insertion loss,isolation,and driving voltage.The switching time is the pull-down time and the response time of the switch.The test results show: in the frequency range of0.1～10GHz,the insertion loss of the SPDT switch is less than 0.54 d B,and the isolation is greater than 22.54 d B;in the frequency range of 10～20GHz,the insertion loss of the SPDT switch is less than 0.99 d B,The isolation is greater than 18.56 d B.The drive voltage of the switch is 52.7V,the switch pull-down time is 40μs,and the switch recovery time is about 200μs. |
