Design Of An L-band High Power Microwave Antenna Based On Leaky Waveguides

With the rapid development of high power microwave(HPM) technology, more and more attentions have been paid to the design of the HPM antenna, which is quite different from the conventional antenna in communication. Due to the particularity of HPM, HPM antenna should meet some special requirements in general, such as compact structure on the premise of ensuring favourable radiation. In order to achieve high-power handing capacity and high radiation efficiency within small apertures in L band, this article investigates a kind of leaky waveguide antenna, and one single leaky waveguide antenna is designed which is short to some extent and easy to serve as a unit to form large scale antenna array with the capacity of beam scanning. The main contents are as follows:1. Investigation of the radiation characteristics of the leaky waveguidesBy employing quasi transmission line theory and perturbation theory, the propagation constant and attenuation constant are acquired according to the equal circuit of the leaky waveguide, which are quite important parameters to describe the radiation characteristics. The theoretical results are compared with simulated results under the conditions of weak coupling radiation, strong coupling radiation and covered by dielectric antenna cover, and the theoretical results is revised based on simulated results.2. Design and optimization of the antenna unitOne single HPM leaky waveguide antenna is designed according to the key parameters of the radiation characteristics obtained above. The structure of the antenna is further optimized by simulation. And the simulated results agree well with the theoretical estimation. The total length of antenna is 2.2 m, the radiation efficiency is 95.7%, the reflection detected at feed port is less than-33 d B the angle between the main beam direction and the axial direction of waveguide is 42°, the sidelobe level is less than-21.2 d B, and the power handing capacity of GW level is achieved.3. Investigation of the antenna arrayIn order to utilize the designed leaky waveguide antenna as the unit of the antenna array, some thorny problems in forming antenna array should be handled well, such as the coupling between the adjacent units and optimization as a whole, and the beam scanning. By theoretical analysis and simulation, an optimized array composed of 9 units is proposed, whose gain keeps above 23.5 d B, in the beam scanning range of-50° to 50°, and the side lobe is less than-10 d B.