Simulation And Design Of High Power Microwave Antenna

Many high-power microwave (HPM) sources utilize an azimuthally symmetric output mode such as the TM 01 circular waveguide or the coaxial TEM mode as output mode. If radiated directly these azimuthally symmetric modes will generate a doughnut-shaped pattern, with a null on boresight. Often, mode conversion techniques are used to change the undesirable mode to one that results in a radiation pattern with a boresight peak such as circular TE1 1 or rectangular TE 01 mode. Unfortunately, mode conversion introduces energy losses, also, the addition of the mode converter adds weight and length to the system. Research and development efforts have been underway for several years to explore a novel antenna concept that can directly accept microwave energy in an azimuthally symmetric mode, with a boresight peak. Usually there are three kinds of design plans of project of the radiation aerial: Mode converter + ordinary horn, VLASOV aerial and COBRA (Coaxial Beam-Roatating Antenna ) aerial.Vlasov antenna is studied systematically. The radiation performance of the antennas is described in detail by clear physical pictures. Based on the simulation results, the Vlasov antennas work in C band are designed, include the Vlasov antenna with single-reflector. At last, a second reflector is added to the single-reflector devise to narrow the beam further, and the antenna gain increased to 20.6dB.This paper also described a novel antenna called the coaxial beam-rotating antenna (COBRA). The radiation performance of the antenna illuminated by a round wave-guide is described in detail by clear physical pictures. Based on the simulation results, a COBRA antenna constituted by four reflectors is designed, the antenna produces a radiation pattern with a boresight peak, and the antenna gain reachs to 28.4dB.