On The Airborne Antennas For The Frequency In The S Band And Ku Band

The research works are made with scientific projects in this thesis. An airborne array antenna, an airborne antenna with specific radiation patterns and a detect antenna are presented. The contexts of the thesis are divided into three parts. An antenna array which performed a characteristic of narrow-beam width is designed and manufactured in part one; A specific radiation antenna is analysised in part two; A detect antenna which based on the technique of Nuclear Quadrupole Resonance (NQR) is given in part three. The context is summarized as following:Firstly, the antenna elements and feeding network which combined by multistage Wilkinson unbalance divider are designed with the requirement of narrow-beam width and low sidelobe characteristics. After the simulation of Ansoft HFSS, an antenna prototype is finally developed. The effect of amplitude distribution on the radiation patterns has been analysised and the measurement results of the antenna prototype were as expected. The VSWR is below 1.5 over the working frequency band. The HPBW is less than 14 degrees in H side and more than 50 degrees in E side. It shows that the design is valuable in engineering practice.Secondly, a specific radiation antenna is designed by Ansoft HFSS. By changing the two cones'angle and height, the antenna's radiation characteristics can be adjusted. Because the antenna would install on the aircraft, it is necessary to consider about the influence of aircraft itself on the antenna radiation. The antenna needs large power capacity, so a waveguide was used as the feeding part, and it also needs to consider about the impact of the waveguide on the radiation pattens. The simulation results show that the VSWR of the antenna is below 2 over the working frequency band. It has an Omni-directional radiation in horizontal plane and provides radiation patterns with gain greater than 2dBi from 65 degrees to 95 degrees in vertical. Then, an antenna prototype was fabricated and tested.Finally, the thesis presented a kind of antenna which is using in explosive detection based on the technique of NQR. The antenna was manufactured and tested. The results show that the antenna performance fulfilled the request.