Theoretical Analysis And Numerical Simulation Of High-Power Radial Line Array Antenna

As the terminal of the high-power microwave (HPM) system, the performance of HPM antenna directly decides that of the whole HPM system. The particularity of high power microwave applies for particular requirements. Many researches have been made at home and abroad. Antenna type includes original antennas, such as mode converter with radiant horn, Vlasov antenna, mode-transducing antenna, and current antenna, such as high-power radial line helical array antenna.High-power radial line helical array antenna reaches comparatively high power-handling capacity due to adopting new-type coupled probe and reasonable feed networks, in addition, it has small axial dimension as a result of adopting radial line as feed waveguide. However, aperture efficiency of the antenna is not ideal. Furthermore, some practical applications require antenna having small transverse dimension, especially in low-frequency range. In this paper, miniaturization of the antenna who works in L-band is carried out, focusing on the aperture efficiency, the main works are as follows.Firstly, configuration parameters of the radiation element are optimized, surrounding the parameters such as gain, axial ratio and so on.Then, the gain of the array antenna whose diameter is given is enhanced, by means of optimizing the layout of array, so as to improve the aperture efficiency of the array antenna. We design a 6-element uniform circular ring array antenna with element spacing of 0.65λ.Theoretical analysis results show that, as for a antenna with a diameter of 320mm who operates in L-band, it's gain is no long increased when the number of elements increase to 8, but the calculated result of 8-element circular ring array antenna is worse than that of the 6-element array antenna. This is caused by mutual coupling between elements. So, in this paper, We reduce the mutual coupling by designing the layout of the array antenna properly, using some multual coupling characteristics of the helical antenna. Consequently, the aperture efficiency is improved. Then, theoretical analysis and numerical simulation is made over the aperture efficiency of the circular ring array antenna as the aperture decrease. Two cases are discussed. One case is the number is constant but element spacing is decreasing; The other is element spacing is constant but number is reducing. This paper also put out ways to improve the performance of the array antenna as for the first case.At last, analysis over power-handling capacity of array antenna is made.