Design On The Feed System Of L-band Multi-unit Slab Waveguide Array Antenna

The rapid development of high power microwave technology has put forward higher requirements for the development of antenna technology,the output power and pulse width of high power microwave have limited the use of traditional antenna technology.Therefore,the antenna technology of high power microwave needs to be extended on the basis of the traditional antenna technology so that it can be applied to strong electric field and short pulse.Besides,it should be satisfied other technical indicator,such as high power capacity,miniaturization,miniaturization,etc.In the process of exploring the application of array antenna to high power radiation,high power radial helical array antenna has been widely studied because of its advantages of high efficiency and simple feeding system.However,the feed structure of spiral array antenna is based on radial line adopts coaxial waveguide input structure,using the coaxial-radial line mode converter to realize the transformation of the coaxial feed to the radial line shape wave.Because of the existence of the input coaxial waveguide,power divider and related connection structure,its axial dimensions are limited to a certain extent and thus affect its low profile characteristics,so it can't be used on some special occasions.Therefore,based on the research of high power radial spiral array antenna.In this paper,the related analysis and validation of the side-fed flat waveguide feed system on the helical array antenna are carried out in l-band,and the important technical indexes are optimized.Firstly,the paper summarizes the theoretical knowledge of high power microwave,array antenna,probe coupling principle,etc.At the same time,the paper analyzes the difficulty of the flat waveguide as a feeding system,that is,how to achieve uniform feed of multiple units in the case of uneven distribution of microwave energy in wave island.Secondly,several probe characteristics are analyzed,the feasibility of using the flat waveguide feed system in L-band 66 is discussed.Finally,on the basis of the original probe structure,a double "L" electromagnetic coupling probe with large coupling volume adjustment range with better reflection characteristics is proposed.A simulation study of the probe was carried out,and the probe was applied to a flat waveguide feed system in L-band 66 unit.In the case of uneven distribution of microwave energy,the continuous feed of each unit is realized.Finally,the problems encountered in the research of the subarray are analyzed,and the optimization scheme for improving the power capacity of the probe and the uniformity of microwave transmission within the flat waveguide is proposed.On the basis of this,the optimized design is carried out for the flat waveguide subarray of the L band 66 unit.Simulation results show that: the reflection coefficient of the center frequency 1.575 GHz is 0.065,the coupling imbalance is 0.726 dB,the axial ratio is 0.88 dB,and the power capacity is 2GW,and it proves the feasibility of using flat waveguide as feed system to improve low profile characteristics of high power spiral array antenna system.