Browsing by Author "Ruppert, Malan Anton Xander"
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- ItemA study on phased-array-feeds for paraboloidal reflector antennas(Stellenbosch : Stellenbosch University, 2017-12) Ruppert, Malan Anton Xander; De Villiers, D. I. L.; Beyers, R. D.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.ENGLISH ABSTRACT: This thesis presents a general study on the use and applications of paraboloidal reflectors utilizing a dense phased array feed (PAF), in the underlying context for use with a receiving Earth station antenna for satellite communication. A theoretical treatment of fundamental concepts useful in the understanding and analysis of PAF system is given, including illustrative examples regarding focal field distribution sampling with an array antenna. The important topic of embedded element patterns, which plays a vital role in including mutual coupling effects in the analysis, is discussed in some detail. A versatile linear numerical framework is created using accurate full-wave simulations and linear microwave-network equations, and combined into a convenient simulation model which can be used to perform various parameter studies on PAF systems. The model allows effects such as various front-end LNA parameters, and beamforming techniques to be investigated. The possibility of including passive array elements, or combining active elements, can also to be investigated. The simulation model is applied to an example 15-element dipole PAF, and a discussion is given on various results regarding beamsteering, optimal beamforming, and receiver noise matching. The possibility of utilizing passive elements along with mutual coupling to reduce array receiver costs is investigated. It is found that more array elements are not always better, given the fact that element contributions to overall system noise outweigh their contribution to gain. Finally, a detailed investigation is carried out on the various trade-of effects between different array configurations and system noise in the context of scanning in a single angular plane. A valuable result is obtained showing identical system SNR performance for arrays using either 9- or 45 elements.