Ultra-wideband Multi-polarization Tracking Antenna And It’s Feed

With the rapid development of space technology, the application of aircraft tends to be universal and diversified. From the perspective of research and national defense, tracking the target aircraft and intercepting the signal information content are increasingly important. In order to achieve the target spacecraft tracking and information interception, a tracking antenna which can satisfy the requirement of indicators is in demand. Therefore, this paper mainly focuses on research and design of tracking antenna from the following respects.Firstly, due to the requirement of the tracking range, application environment, the kind of polarization and other design indexes, a large aperture reflector antenna is designed to achieve the target tracking and information intercepted. The feed of reflector antenna is simulated by HFSS, then calculating Secondary pattern through FEKO simulation and programming calculation. The results show that the calculation results of two methods are consistent.Secondly, in order to solve the wideband problem of tracking antenna, eight log-periodic array antenna elements are used to constitute the reflector feed. In order to reduce the weight of feed and the load of support bar, the log-periodic antenna is designed based on PCB. The phase center distribution problem of LPDA antenna has been studied in detail using programming. And a qualified LPDA antenna is designed using electromagnetic simulation software, analyzes the influence of structure parameters on the radiation characteristics at the same time. The test result of LPDA antenna show that the design satisfies the requirement of indicators.Thirdly, the design of structure, amplitude and phase of feed are probed so as to realize three operation mode, those are linear polarization, left-handed circular polarization and right-handed circularly polarized. Tolerance analysis is carried out on the feed phase and amplitude, which has a guiding significance for the index distribution o phase shifter and beam synthetic network.Fourth, in order to achieve stable performance in the wide band, especially the cross level of cross beam stability between-3db to-8db, this paper investigates the secondary pattern performance for feed displacement, and combined with phase center distribution of LPDA antenna to realizes stable cross level.Fifthly, in order to solve the feed structure’s influence on the radiation characteristics exposed in test, this paper studies several common feed structures, and propose a way of punching to feed, so as to solve the influence of feed structure on antenna radiation characteristics.Finally, the tracking antenna designed in this paper is processed and tested in anechoic chamber with problems solved in the test. The test results show that the tracking antenna meets perfectly the requirement of the designed performance and the actual demand.