A Study Of Ka-band Offset Reflector Antenna

With the rapid development of science and technology, people’s living standards and the requirements of modern society have continuously improved, at the same time,electronic technology’s using has also put forward higher requirements, as an important device radio antenna, so its development trend has become increasingly active to recent developing. Reflector antenna as an very important antenna form, Because of its high gain characteristics, Reflect antenna become a common form of radar antenna. More and more scholars and researchers pay a attention to study this antenna. In this paper,the author have studied the reflector antenna which work at Ka-band.In this paper the author mainly introduced a new corrugate feed horn which change the structure of corrugate tank. Through this changes we found that the corrugations will be parallel with the horizontal axis of the horn. So that this horn will be easier stripping relative to the general horn and it can be manufacture by the die casting method. Using this horn as a feed of the reflector antenna the diameter of this antenna is 0.75 m and0.9m.,then simulate them by CST simulation software. In the meanwhile, the author choose the most appropriate angle to lead to the gain and the edge illumination of a single offset reflector antenna which the author designed achieve the best condition.Because this antenna is designed primarily for satellite communications, This paper also discusses the gain and the sidelobe envelop of the partial feed reflector antenna.Firstly, in this paper the author made a brief introduction of the base knowledge of reflector antenna and then introduced the method of how to eliminate the influence of the feed horn on the reflector, and then analysis the pros and cons of each method.Finally the author select bias feed method and chose the form of single offset reflector antenna as the ultimate form.Under the premise of determining the aperture of reflector antenna,the author discussed how to select the focal diameter ratio and determine the most appropriate focal diameter ratio by using CST simulation software.In the meanwhile, When the focal diameter ratio was determined, the author select and optimize the angle which is between the lower edge of reflecting surface and the maximum radiation direction of the partial reflector antenna feed by Using CST simulation software,then the author choose the most appropriate angle which enable thegain and the edge illumination level of this antenna to the best condition. Because this antenna is designed primarily for satellite communication, This paper also discusses the gain and the sidelobe envelop of the partial feed reflector antenna.Secondly, satellite communications antenna system requires the feed have high effective performance such as:low cross polarization, low return loss. Because it has low sidelobe and low back lobe as well as its pattern has a good circular symmetry, it has replaced the traditional E smooth wall horn which tangential magnetic field is parallel to the walls as the feed of reflector antenna. In this paper,the author describe the design method of feed horn. According to the above content, the author designed the horn of the single offset reflector antenna. In the design of conical corrugated horn, the author mainly introduced a new corrugate feed horn which change the structure of corrugate tank.Through this changes we found that the corrugations will be parallel with the horizontal axis of the horn. So that this horn will be easier stripping relative to the general horn and it can be manufacture by the die casting method. At the same time, in this paper the author determined that the feed horn which was designed by author has a better equalization characteristics and phase stability by using CST simulation software simulating.