Research On Square Coaxial Microwave Power Divider Based On 3D Printing Technology

As an important part of microwave circuit,power divider can be seen in almost every microwave RF circuit.It plays a very important role in communication system.As the key device of various microwave equipment,it receives great attention.At the same time,it is also required high performance from broadband,isolation and VSWR,but also the volume,weight,cost and power.Therefore,it is particularly important to find new manufacturing and design ways to meet the increasing engineering needs.Based on this,from the perspective of process innovation,this thesis studies the design and processing of power divider by using coaxial transmission line and 3D printing technology.It includes the following contents:1.Based on the basic theory of square coaxial transmission line,the influence of structure parameters on transmission performance is deeply analyzed,and combined with the actual implementation method,the optimal design method of transmission line is given.Considering the factors that may affect the insertion loss in the actual assembly process,the sidewall gap,conductor material and surface roughness are analyzed.Finally,the transmission line is processed and measured by using 3D printing process and traditional CNC process.The difference between the test results and the simulation results is only 0.1d B,which realizes the feasibility of square coaxial transmission structure under 3D printing process and lays a foundation for the processing design of power divider.2.Based on the theory of multistage Wilkinson power divider,a broadband power divider with bandwidth of 100%is designed,and the overall working frequency covers 0.5-1.5GHz.Firstly,a broadband coaxial power divider covering 0.5-1.5GHz is designed and fabricated with 3-class connection structure,and the overall size is 75×85×15mm~3.In order to reduce the size of the power divider and give full play to the advantages of 3D printing technology,the single-layer structure is folded into a double-layer structure.The measurement result shows that the retrun loss and the isolation of output ports is greater than 20d B in the frequency range of 0.5-1.5GHz.And the insertion loss is around 3.5d B.The overall size of power divider is reduced to 45×76×23mm~3.3.The 3D printing can realize the flexible processing of complex structure,which solves the problem that it is difficult to load the isolation resistance of the traditional multi-channel Wilkinson power divider.By optimizing the topology scheme of multi-channel power divider,two Wilkinson power dividers with center frequency of 1GHz are designed respectively.Finally,a four channel Wilkinson power divider is processed and measured.The test results and simulation results show that in the frequency range of 0.75-1.25GHz,the return loss of the input and output ports of the power divider is greater than 20d B,the isolation between the output ports is greater than 20d B,the insertion loss is about 6.18db,and the overall size of the power divider is 94×94×72.5mm3.