Research On Power Divider With Equal-ripple Reflection And Isolation In Short-circuited Stubs Structure

With the rapid development of the communication industry,the wireless communication system is developing towards the direction of large capacity,high speed,miniaturization and integration.The design of microwave passive devices plays a crucial role in improving the overall performance of the communication system.As one of the key passive components,power divider plays an indispensable role in the wireless communication system.With the promotion of the fifth-generation communication system and the increase of information interaction,the performance of the traditional power divider has been unable to meet the requirements of such a multi-standard system.In order to meet the demand of bandwidth,the integrated design of wideband filter has always been one of the hot research issues.However,most of the former works only focus on realizing performance of S₁₁ and S₂₁,the analyzing approach to improve the performance of S₂₂ and S₃₂ is also important in filtering power divider design.Thus,this paper proposes a design method of the filtering wideband power divider with equal-ripple reflection and isolation.The work contents are summarized as follows:Firstly,this paper analyzes the traditional Chebyshev corrugated filter and Wilkinson power divider based on the basic principle of port network.The principle and constraint conditions of Chebyshev equal-ripple filter are described.The even-odd mode circuit model of the Wilkinson power divider is deduced,and the matching conditions at a certain frequency point are defined.On this basis,the comprehensive design method of Chebyshev filtering impedance transformer based on short-circuited-stubs structure is proposed in this paper.The circuit model of N order transverse transmission line and N+1 short-circuited-stubs structure is analyzed,and the S parameters can be approximated to Chebyshev and other ripples while the impedance transformation can be realized.According to the relationship between variables and constraints,a detailed analysis of the impedance diagram is made with the following points:1.Impedance conversion ratio 2.Number of short-circuited stubs 3.Position of short-circuited stubs.Secondly,the design method of power divider based on short-circuited stubs structure with internal equal-ripple reflection and isolation effect is proposed.The method of even-odd mode analysis is used to analyze the power divider of short-circuited stubs,and the inductive formula for calculating[S]matrix is shown.In the even-mode analysis,the Chebyshev filtering impedance transformer is used to realize.In the odd-mode analysis,the inductive formula is used to constrain S₂₂ and S₂₃,and the effect of ripple reflection and isolation in the passband is realized.Due to the complexity of the formula and the correlation between variables,the design conditions cannot be completed under specific conditions.In this paper,the optimization method is proposed and the design method is improved.Finally,this paper uses the optimization method to design the power divider of the three-order transmission line and four short-circuited stubs.To verify our optimization method,a power divider is finally designed,fabricated and measured.It uses the coupling transmission line instead of the traditional transmission line,so that the circuit size is smaller and the fabrication is simple.