Study On The Technology Of The Rectangular Coaxial Transmission Line Of Metal

In recent years,the development and application of airborne radar,low altitude missile system and phased array radar have made demands on microwave circuit for high integration requirements to reduce its size and weight,and improve reliability and the frequency band.Monolithic microwave integrated circuits meet the requirements of high integration,so it emerges due to the advantages of high integration,low cost and high performance.Rectangular coaxial metal transmission line is key to realize the miniaturization and lightening of monolithic microwave integrated circuits.The transmission line is a complex three-dimensional structure of micrometer-scale,and its fabrication technology is quite intricate.Based on this,we have carried out the research on the processing technology of rectangular coaxial metal microstructure.Based on UV-LIGA technology using BPN with SU-8 negative photoresist,the microstructure of rectangular coaxial metal transmission line was fabricated.The microstructure of the film was prepared by BPN,and the film support of the inner conductor was made by SU-8.Finally,the rectangular coaxial metal transmission line can be obtained by electroforming and resist lift-off process.In this paper,three design projects of processing technology of the rectangular coaxial metal transmission line were introduced,including layer by layer stacking technology,indirect bonding technology and the outer conductor with one step.Based on the outer conductor with one step of a molding process technology,the process has been carried out for optimization,which aims at improving the overall quality of the finished product,shortening the proceesing time,lowering cost.Here,some key problems were investigated during the experiment,including the coating of thick BPN resist and the deposition of thick metal during electroforming,and the corresponding solutions were put forward.Finally,the samples of the transmission line were detected,including the size of the structure,such as thickness,height,length,width of inner and the surface and overall profile.Test results showed that the processed surface morphology and the outline were comparatively ideal,and the size was within acceptable error.