Research On Ka Dual Band Circularly Polarized Reflector Antenna

As the increasingly demand on the amount of information and communication rate, traditional satellite communication is difficult to meet the growing demand. In this situation, the research of K and Ka band,even more high frequency satellite communications gradually become a hot spot. In order to meet the need of motion platform,such as Satcom-on-the-move, and against the transmission mismatch when high-frequency radio waves transmitting in the atmosphere, the circularly polarized wave is used. At the same time, the circularly polarized reflector antenna with high gain can be achieved when the mode of the microwave is circular porlarization.The hat feed with self-supported structure,a relatively popular spot in foreign countries,is used as the reflector antenna feed rather than the corrugated horn,which can improve the aperture efficiency and reduce the sidelobe level.A hat feed ring-focus reflector antenna working at Ka dual and broad band is designed. The mode of the microwave is circular polarization.The main purpose of the desing is used in the ship on-the-move.The main work is as follows:First, two kinds of circular polarized device working at Ka dual band is presented. Through theoretical analysis, simulation and optimization of the CST, the suitable size of the devices can be obtained.And one of the devices is made.The test result shows that the phase deviation is between 87 to 99 degrees, which shows the performance of the designed device is well made.Second,a hat feed is simulated and made.The well pattern of the feed can be achieved by calling the genetic algorithm in the CST. The simulated results shows that the suitable size can guaranteed the energy focusing the effective range of the main reflector.At last, a kind of ring-focus hat feed reflector antenna is researched and presented.Through designing the parabolic curve and ring radius, the good simulated resulted can be obtained by parameters sweeping and optimazating in CST. The simulated model is made and tested.The results show that the antenna has high efficiency and low sidelobe,whose pattern can meet the the European Telecommunications Satellite FCC standard.