High-power Microwave Antenna Based On Rotman Lens

Recent years,with the continuous development of pulse power technology,the peak power of high power microwave sources has been continuously improved,making high power microwave technology from theoretical research to practical application.Compared with the development of high power microwave sources,high power microwave antennas have become an important factor limiting the development of high power microwave systems.In order to achieve fast scanning of a beam in a high power microwave environment,a phased array antenna based on a phase shifter has conventionally been used.The phased array antenna,due to the high cost of the phase shifter module,limits its development to a larger scale and also limits its application in the high power microwave field.Compared with the phased array antenna,the antenna technology using the multi-beam forming network has received extensive attention due to its lower cost and easier processing advantages.The Rotman lens is a multi-beamforming network based on the quasi-optical principle.The beam scanning is achieved by switching the feed ports.It was proposed by Rotman in 1963 that it received extensive attention and improvement from researchers and got some applications.Its advantages such as wide frequency band,multi-beam,true delay,simple design and low cost can be applied in high power microwave systems.Therefore,it has important research significance.The main content of this article is as follows:The working principle of the Rotman lens is analyzed,the phase distribution and amplitude distribution of the Rotman lens are studied,and the influence of multiple variables on the lens performance is analyzed.The application of Rotman lens antenna in high power microwave environment was studied first time.In order to apply the Rotman lens to high power microwave environment,we try to use the flat plate structure.According to increase the distance of the flat plate to increase the power capacity,and optimize the design of the port distribution and the transmission line to decrease the reflection of the Rotman lens.capacity.In this paper,the main reasons affecting the power capacity of the Rotman lens antenna are studied,and a Rotman lens antenna working at 9.4 GHz is designed.The scanning angle of the antenna can reach ±22°,the gain in each direction is greater than 16.5 dBi,and the efficiency is about 60%.The power capacity after adding the antenna windows is about 300 MW.The transmission and radiation characteristics of Rotman lens antenna with high power capacity are studied by electromagnetic simulation program.For the problem of excessively large size of transmission lines,the use of unequal-width waveguides instead of equal-width transmission lines reduces the size of the transmission line section of the flat Rotman lens antenna;for the problem that the level of the Rotman lens antenna side-lobes is too high,through the adjacent ports at the same time The feed method improves the amplitude distribution of the output port and reduces the sidelobe level of the Rotman lens antenna.Finally,the two-dimensional scanning using Rotman lens antenna is studied and verified by simulation.