Design And Fabrication Of Microwave Filter Based On Metal Microcoaxial Structure

With 5G technology mature gradually,and the relevant requirements of microwave radio frequency devices of high frequency band adaptation is also growing,including the structure design and performance optimization of microwave filter become one of the important research topic in the field of radio frequency communication today,the role of the filter is retained within the specific frequency band signal,filter in addition to the specific frequency band signal,so as to improve the SNR of the signal.The optimization of a series of parameters,such as rectangular coefficient,return loss,quality factor,out-of-band suppression,insertion loss,etc.,has gradually become a research hotspot,and has been widely used in the field of satellite and ground communication,military equipment,aerospace,commercial communication and other fields.After the research and analysis of the design principle of microwave filter and the advantages and disadvantages of the current structure,based on the metal microcoaxial structure,this paper designs a high-frequency bandpass filter in the form of short transversal.Its center frequency is 28 GHz,and the relative bandwidth of 3d B in the passband is 20.3%.The design analysis,simulation optimization,plate-making processing and test comparison of bandpass filter devices are completed.The main contents include the construction and simulation optimization of the metal microcoaxial filter model,the determination and improvement of the specific processing technology,the construction and calibration of the experimental test platform,etc.Firstly,the design and simulation of the filter are carried out.The microwave filter based on the metal micro-coaxial structure is mainly composed of an inner conductor,an outer conductor and an insulating support material.The inner conductor is used for the transmission of electromagnetic waves.The outer conductor is grounded to provide shielding environment for the inner conductor;The insulating support material not only separates the inner and outer conductors and provides air as the medium for the electromagnetic signal transmission of the inner conductor,but also provides stable supporting force for the inner conductor.The specific device Structure is designed and optimized by Advanced Design System(ADS)and High Frequency Structure Simulator(HFSS)software to realize the established parameters of microwave filter.The minimum insertion loss in the passband is greater than-1.19 d B,and the out-of-band suppression in the bands greater than 38 GHz and less than 18 GHz is less than-47 d B and-30 d B,respectively.Secondly,after determining the filter structure and specific size,L-EDIT software is used to draw the processing mask layer based on the three-dimensional model of microwave filter.After lithography,electroplating,Chemical Mechanical polishing,CMP)and other processing technologies to achieve the physical production of metal micro-coaxial structure microwave filters based on Polystrata technology.Finally,by using high frequency probe and microwave filter performance testing and analysis network analyzer,will test the S parameters compared with two simulation results,mainly compare the insertion loss,return loss,and key parameters such as relative bandwidth restraint outside the band finally met at present actual usage scenarios of metal micro coaxial microwave filter structure,Verify the reasonableness of the microwave filter design.