Researching On Ultra-wideband Transmission Line Transformer Series Devices

With the rapid development of radio frequency wireless communication systems,ultra-wideband,low cost,strong anti-interference ability and other characteristics have become a research hotspot of RF circuits.Various types of RF electronic devices,such as impedance transformers and power dividers,have the advantages of ultra-wideband,easy integration,and small size.Therefore,it is of great significance and value to deeply study the types of transmission line transformers.Based on the research of ultra-wideband technology and the knowledge of transmission line transformers,through in-depth study of impedance transformation technology and power synthesis distribution technology,this thesis makes a detailed analysis and summary of several important basic circuit units,and then designs several ultra-wideband transmission line transformer devices according to the analysis results.The main work is as follows:(1)A detailed analysis of the commonly used two-line impedance transform unit and three-wire impedance transform unit,such a transform is widely used in practical circuits,and at the same time gives a design method of arbitrary impedance transform ratio;(2)Analyzing the basic characteristics of the power distribution/synthesis network consisting of UWB transmission line transformers,including the basic two-way and three-way power distribution units,and summarize the methods for implementing different power allocation units;(3)Studying the influence of different winding materials and winding angle of the transmission line on the characteristics of the transmission line,and analyzing the core material used in the transmission line transformer;(4)According to the relevant theory and design requirements of UWB transmission line transformers,two 1:4 impedance converters were realized and tested,including 50 ohm to 200 ohm and 12.5 ohm to 50 ohm converters.A two-way power divider with 50 ohm input and output and two four-way power dividers with 50 ohm input and output.The designed circuit frequency ranges from a few megahertz to a few hundred hertz,all of which are ultra-wideband,compact,and small in size,while providing excellent performance in their respective frequency bands.In this thesis,ADS(Advanced Design System)is used for simulation debugging,and R&S(Rohde&Schwarz vector network analyzer)is used for actual measurement analysis and improvement.Finally,a transmission line transformer type device with ultra-wideband is obtained,this has certain engineering value and practical significance for the research of RF broadband devices.