Research On Ultra Wideband Power Dividers With Arbitrary Number Of Channels

The microwave power divider is an indispensable device in the microwave system.In recent years,researchers have developed many ultra-wideband power dividers with excellent performance,which are widely used in wireless communication,radar and other fields.At present,the vast majority of ultra-wideband power dividers are composed of microstrip lines and strip lines.Compared to metal waveguides,microstrip and stripline have high insertion loss and low power capacity.Therefore,they are not suitable for applications with low insertion loss and high power capacity.To overcome these problems this thesis proposes a design idea of a metal waveguide ultra-broadband power divider.The power divider is designed based on the idea that uses two transmission lines,the coaxial line and the single-ridge rectangular waveguide.The input port of the power divider is a coaxial line.The output ports are single-ridge rectangular waveguides which are arranged with equal angle around the coaxial line,with each ridge connected to the inner conductor of the coaxial line.The impedance matching structure between the output ports and the input port of the power divider consists of coaxial line and ridge steps.The structure of the power divider can be regarded as an extension of the traditional T-junction waveguide power divider,but with arbitrary number of channels.The main work of this thesis is as follows:1.The ultra-wideband transmission lines such as coaxial line and single-ridge rectangular waveguide are introduced,and the transmission characteristics of the Tjunction waveguide power divider are analyzed;2.To overcome these problems of the three-way power divider based on the traditional T-junction waveguide,a structure that can realize the three-way ultrawideband power division is proposed.The work of designing the power divider is mainly divided into two parts.One part is to verify that the basic structure of the power divider can realize the function of three-way power equal division and to determine the structure size of the coaxial line of the input port;the other part is to determine the structure of the impedance matching between input port of the basic structure and standard SMA coaxial connector.The power divider has a simple structure and is easy to process and assemble.The simulation results show that in the frequency range of 6 GHz-18 GHz,the return loss of the power divider is greater than 15.5 d B,and the insertion loss is less than 0.11 d B.The amplitude balance between each output port is less than d B,and the phase balance is less than;3.Based on the design concept of the three-way ultra-wideband power divider,an idea that can design ultra-wideband power dividers with arbitrary number of channels is proposed,and the five-way,seven-way and nine-way ultra-wideband power dividers are designed based on the idea.Then,the transmission characteristics of these power dividers are analyzed through the scattering matrix.At last the simulation results of these power dividers are introduced;4.The ridged waveguide coaxial ultra-wideband transition is designed,and the design process of the transition is introduced in detail.The matching structure of the transition is mainly composed of the ridges,the wide wall of the waveguide where the ridges are located,the narrow walls on both sides of the waveguide and the short-circuit reflecting wall.The simulation results show that in the frequency range of 6GHz-18 GHz,the return loss of the transition is greater than 20 d B,and the insertion loss is less than0.05 d B;5.Process and test the three-way ultra-broadband power divider and the ridge waveguide coaxial ultra-broadband transition.