Design Of X-band Amplitude Comparison Antenna And It's Feeding Network

The overall work of this paper is to design a circular-polarized amplitudecomparison waveguide slot antenna working in the X-band,and do some research on the feed network of this type of antenna.This article summarizes the relevant basic principles that will be used when designing the antenna,and details the design method and process of the entire antenna.Starting with a single radiating element's design,this article selected the appropriate rectangular waveguide related parameters in conjunction with the required antenna,and designed the circular polarizer parameters,and then designed the parameters of circular polarizer which is suitable for the entire antenna array.Taylor synthesis was used in the design of the radition planar,and the theoretical value of the excitation distribution at the side lobe level of-22 dB was calculated.The theoretical admittance of each element of the radiation array was calculated by combining with the analysis of the equivalent circuit of the waveguide slot.The corresponding model was established in the high-frequency simulation software,the parameters of each longitudinal slot were extracted,and finally the entire radiation array was established.The main innovation work of this paper focuses on the design of antenna feeding networks,especially the design of coupled waveguide.For the feeding network,this paper first designs a classic coupling waveguide using a wide-side longitudinal slot feed,combines its equivalent circuit,calculates the theoretical impedance distribution of this feeding form,and uses a half-plane array simulation to extract the coupling slots' parameters.H-T junction-fed coupled waveguide structures have not been used since they were proposed due to difficulty in impedance matching and narrow bandwidth.This article addresses the above issues and applies them to a amplitude-comparasion antenna,which improves the antenna's bandwidth.By adjusting the coupling slots near the joint,the pattern performance is taken into consideration while obtaining a good match.This paper also proposed a new type of broadband H-T junction and a one-to-four power divider.After simulation,the relative bandwidth of-10 dB can reach more than 40%,and it has good amplitude and phase characteristics.In this paper,the new H-T junction is also used in the design of the feeding network.However,due to the influence of the bandwidth of the radiation array itself,the bandwidth of the feeding structure using the new H-T junction has not been significantly improved.In order to intuitively see the difference of those three structures,an ideal model is established in this paper.The results obtained from the simulation of the ideal model are as below: the relative bandwidth of the structure which using the traditional wide-wall longitudinal slot feed coupled waveguide is 8%.The structure using the planar H-T junction feed has a relative bandwidth of 10%,and the structure using the new H-T junction feed proposed in this paper has a relative bandwidth of 11%.This verifies the H-T junction,especially the new H-T junction's contribution of improving feeding network's bandwidth.