Study On Integrated Structural-electromagnetic Analysis Of Cassegrain Antennas

Structure errors always exist during manufacture, installation and working process of a reflector antenna. These errors which may affect the electromagnetic performances of the antenna include surface errors of the main reflector, position errors of the feed and the subreflector, and rotation error of the subreflector,etc. Various errors are usually considered separately in the existing related literatures. Actually, various structure errors always exist simultaneously, and jointly affect the radiation performances of the antenna. Thus, the structure errors should be taken into account simultaneously and the radiation performances should be analyzed by integarating structural and electormagnetic analysis. The integrated structural-electromagnetic analysis of Cassegrain antennas is studied in the thesis. The main works are as following:1. A method of computing the power pattern of an antenna with various structure errors based on the geometric optics method is proposed. The errors considered include main reflector errors, feed position errors, subreflector position errors, and subreflector rotation errors. A formula of computing the power pattern is derived by considering simultaneously various errors, and the computation methods for evaluating several radiation performances is given.2. A realization process for integrated structural-electromagnetic analysis of Cassegrain antennas is proposed. The structural analysis is performed by using Ansys. Various structure errors are extracted and computed by using the distortion information of the structure. A Matlab program is written for the realization of the whole process. An 8-meter Cassegrain antenna is analyzed and discussed by using the program.3. The compensation relationships of the structure errors are discussed by numerical examples. Some errors can alleviate the deterioration of the radiation performances caused by some other errors. Analyzing and summarizing various compensation relations among the structure errors can offer valuable reference for the design and adjustment of the antenna structures.