| Antenna is the transmitter of high-power microwave（HPM）system.Its main function is to beam the microwave generated by high-power microwave source and transmit it to the target directionally.Its performance is very important.Waveguide slot antenna has many advantages,such as compact structure,light weight,high-power handing capacity,high gain and convenient array,so it is widely used in the field of high-power microwave.With the development of high-power microwave technology,the requirements for antennas are no longer limited to high-power handing capacity and high gain,but have more functions and uses on the premise of ensuring high-power handing capacity and high gain.Under this background,the research of high-power slot array waveguide antenna is carried out in this paper.The main content of this paper includes the following aspects:（1）Based on the basic theory of slot antenna,the design principles of rectangular waveguide slot antenna and array antenna are described,and a high-power waveguide slot array antenna is designed.The equivalent conductance corresponding to the antenna aperture distribution curve is designed by the equivalent transmission line theory to meet the needs of high-power microwave applications;the mutual coupling between the slot waveguides in the process of antenna array is studied and discussed;in order to provide a vacuum environment for the array antenna,a matching radome is designed.Finally,the maximum gain of the single waveguide slot antenna is 26.5d Bi,the power handing capacity is 644MW,at the centre frequency 8.4GHz,|S11|=-43.1d B,|S21|=-10.3d B,the radiation efficiency is more than 99%.After that,a single antenna is processed and tested,and the actual test results are basically consistent with the simulation results.The array antenna is composed of 16 slotted waveguides longitudinally,the maximum gain is 39.9d Bi,the total power capacity is above 10GW,the main lobe direction of plane E deviates from normal by 3.1°,the 3d B gain beam-widths in E plane is 0.9°,and the 3d B gain beam-widths in H plane is 3.6°,which is a pen beam and has good directivity.（2）A circular polarization waveguide slot array antenna is designed to solve the problem that the high-power slot antenna radiates linearly polarized waves and has low coupling efficiency with the target.Based on the waveguide slot array antenna,the cross polarization can be reduced by making the two adjacent rectangular slot waveguides mirror symmetric about the central plane of the two waveguides and the the feed signals of these two waveguides are equal and the phases are reversed.The angle between all-metal grid structure and slot waveguide is 45oand there is a certain distance between them,so as to realize high-power microwave circularly polarized radiation.The simulated results indicate that the maximum gain of the array antenna is 39.9d Bi,the total power handing capacity is greater than 10GW.The 3d B gain beam-widths in E plane and H plane are 0.8°and 3.4°,and the beam-widths for the axial ratio less than 1d B are 1.7°and 7.3o,respectively.The results show that the antenna has good directivity and the axis in the beam range is relatively low.（3）Aiming at the shortcomings of the current high-power waveguide slot antenna,which has a long filling time and a short flat top time of the antenna output signal,a high-power waveguide slot antenna with intermediate feed was designed.The antenna has a feed waveguide in the centre of the narrow side of the slot waveguide.After the microwave signal is input from the feed waveguide,the microwave signal is transmitted from the middle of the slot waveguide to both ends at the same time.When the slot waveguide is of the same length,the filling time is shortened to half that of the end-fed slot antenna,which greatly reduces the flattening time loss of the radiation signal,and the central axis of the feed waveguide is coaxial with the microwave radiation direction.The simulation results show that when the rising edge and falling edge time of the excitation signal are both 6ns and the flattening time is33ns,the flattening time of the output signal of the antenna is 21%longer than that of the side-fed waveguide slot antenna of the same length,and the far-field radiation performance indexes of the two are basically the same.The maximum gain of the centrally fed high power waveguide slot antenna is 26.7d Bi,and the power capacity is508MW.At the centre frequency 8.4GHz,|S11|=-33.4d B,radiation efficiency is more than 99%,the 3d B gain beam-widths in E plane and H plane are 0.7°and 86.8°respectively. |
