Study And Design On The Wideband Transition Between Different Microwave Lines

With the advent of artificial intelligence era,integrated circuits have gained more and more attention.As an important part of integrated circuits,microwave integrated circuits have been rapidly developed.Miniaturization and high integration have become the development trend of microwave circuits.Different transmission lines have different advantages and disadvantages,so there will be different types of microwave transmission lines in microwave integrated circuits.Due to the increasing level of integration,3D integration technologies are becoming more and more common.The transmission of microwave signals is no longer limited to the same plane of transmission,and signals are sometimes transmitted between multilayer circuits.It is of great significance to study how to realize the transition between different kinds of microwave transmission lines and how to realize the transmission of microwave signals in different layers.For these two issues,this paper mainly carried out the following work:Firstly,the transmission properties of four kinds of common microwave transmission lines?microstrip,rectangular waveguide,coaxial line,coplanar waveguide?,transmission line circuit theory and several commonly used impedance transformation methods are analyzed to provide a theoretical basis and initial model reference for the design of transitional structures.Secondly,several common structures of coplanar waveguide to microstrip line were studied,the transmission principle of some transitional structures was analyzed,and a coupled asymptotic transition structure was designed.After modeling in three-dimensional simulation software,as a result,in the 8 to 12 GHz band,?S₂₂?<-26.4dB,?S₁₁?<-26.4dB,and?S₂₁?>-0.02dB.Subsequently,several kinds of transitional structures from rectangular waveguides to microstrip lines were analyzed and an E-plane microstrip probe-type transition structure was designed.The simulation results show that in the range of24.5 to 36 GHz,?S₂₁?>-0.2dB and?S₁₁?<-15dB.Both simulation model structures can meet general practical engineering needs.Finally,several common microstrip line-microstrip line vertical transition structures are introduced and analyzed.Based on the type of metallized vias,a new microstrip line-microstrip line vertical transition structure was designed.In the upper and lower two microstrip lines,two matching nodes are used for matching.At the metallized vias where microstrip lines and insulators are connected,the size and number of air chambers are optimized to match.Taking into account the current machining accuracy and cost,the size of the processed object changed compared to the size of the simulation model.The physical test results show that?S₂₁?>-2.7dB?including two K-2.92mm connectors and microstrip transmission line losses?in the frequency band of 0.5 to 38GHz,and?S₁₁?<-9dB.The structure has the advantages of wideband,stable performance,good repeatability,etc.It provides a new feasible structural scheme for the vertical transition of microstrip lines between different layers.