The Parabolic Antenna Main Defocusing Multiple Feed Technology Research

Antenna is an important component of radio system. Driven by the continuous development of radio communication technology, challenging antenna topics such as bandwidth widening, function augmentation and performance improvement have become the primary tasks to be accomplished by antenna researchers nowadays.In this thesis, a series of investigation on the performance of antenna system modified by adding sub-feed to main feed or sub-reflector on large or medium-sized paraboloidal aperture antenna has been carried out. Corresponding conclusions are drawn to provide theoretical guidance to the application of research results in expanding antenna bandwidth in engineering practices. Firstly, offset paraboloidal reflector antenna and antenna array are discussed based on the basic electromagnetic theories and antenna theories. Secondly, conventional HF approximation methods, software as well as algorithmic rules in use are briefly introduced and compared, and then the antenna simulation software FEKO used in this work along with such methods as MoM, MLFMM, and PO are elucidated at full length. Thirdly, the parametric influences on antenna performance are analyzed by collecting simulation data from antenna system with offset feed installed at different locations and working at various orientations. The regularity and reliability of simulation results are also testified with actual measurements. Lastly, the applicable arrays of offset feed for signal reception under different conditions are summarized and in the mean time, relevant future work is proposed.