Design On The Feed System Of S-band Multi-unit Radial Line Array Antenna

As the terminal of the high-power microwave systems, high power microwave antenna system’s performance will have a direct impact on the performance of the entire high-power microwave systems. In the development of high-power microwave antenna. Beside deep study and some progress for achieving high power capacity, high gain and high efficiency has been made,with maturing of high-power microwave technology, scholars begin to focus on the aspects of high-power microwave antenna’s miniaturization and lighter.Because of the advantages of small size, light weight, high efficiency, array antenna fed from radial waveguide had gotten wide attention and rapid development since1990s.In recent years, through the use of electromagnetic coupling probe, people successfully applied the array antenna fed from radial line in the field of high-power microwave, and proposed design idea of assembled rectangular radial line helical array antenna, which is using the assembled rectangular radial line sub-array as a core, and through close combination of several sub-array by using a multiport power divider to form a larger rectangular radial line array antenna, thus to attain the purpose of improving the gain.However, to achieve a higher gain, we need to combine more radial line sub-array, which will lead to the complexity of the low-level power divider network, and more insertion loss as well. Therefore, in order to reduce the insertion loss as much as possible at the same time to achieve a higher gain, a new design idea of multiport radial line sub-array is proposed, which is increasing the unit number of a single radial line sub-array to improve the gain and reduce cascade of low-level power divider, so as to attain the purpose of reducing insertion loss.The paper firstly study and summary the theories related to the research, include basic theory of the array antenna, transmission characteristics of radial waveguide, principle of coupling probe and so on. The same time, the principle of the assembled radial line helical array antenna is also studied to have a certain understanding of the emphasis and difficulty in the design progress of this type radial line sub-array:because of the transmission characteristics of radial waveguide, microwave transmission in the radial line is no longer uniform with the expansion of the array surface, which results the more difficulty of attaining the equal amplitude export. So the first work is to achieve the equal amplitude export of the feed network of multiport radial line sub-array.To achieve the equal amplitude export, design of coupling probe meeting the requirements is the chief problem in the design of feed network. The paper simulate and study the coupling characteristics of some original form probes, having a comprehensive understanding of the regular patter of probe coupling characteristics with dimensional changes. On this basis, the paper proposes three new structure of coupling probe, and carries out simulating study of them to grasp the coupling law. Through the use of new coupling probe, the paper complies the equal amplitude output of64-unit rectangular grid and66-unit triangular grid radial line sub-array feeding network for the first time, and verifies the feasibility of the design of multi-unit radial-line sub-array’s feeding network by experimentNext, an analysis and study of the results and problems encountered in the design progress is made, as well as an optimized simulation and experimental study of the triangular grid of66-unit radial line sub-array through improving the probe form and using a new microwave distribution, the test results show that, the array reflect is0.084,the radiation gain is25.19dB, axis ratio is0.82dB at the center frequency. So as to prove the feasibility of a multi-unit triangular grid radial line sub-array’s feeding system design.Basing on the research of sub-arrays above, the paper make a further study of a more number of92-unit triangular grid radial line sub-array’s feeding network, and complete the feeding network successfully. The test results show the reflect of0.052,the gain of25.23dB, and axial ratio of0.45dB at the center frequency, and the ability to achieve the circularly polarized radiation.