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Modeling And Optimization Design Of Phased Array Feeding System For FAST Radio Telescope

Posted on:2016-06-18Degree:MasterType:Thesis
Country:ChinaCandidate:L L TangFull Text:PDF
GTID:2132330461981195Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
Radio telescope plays a very important role in astronomy. Five-hundred-meters aperture spherical radio telescope (FAST) will be the largest and most sensitive radio telescope. The most important property in radio telescope is effective field-of-view (FoV), phased array feeds (PAF) offer the capability for multiple simultaneous beam formation and wide field of view for telescope, which greatly enhances the survey speed (SS), so PAF will be one of the key technologies for next generation of radio telescopes.In this thesis, the modeling and optimization design of system are presented. First, the framework and principle of every model are analyzed, modeling of reflector, analysis of focal plane and maximum signal to noise ratio (max-SNR) beamformer are also studied. The formulas of property parameters are deduced based on the signal analysis of every model. Second, principle and implementation process of several impedance matching methods are introduced in detail, as the mismatch between PAF and low noise amplifier (LNA) can largely increase system noise of radio telescope, which results in the degradation of the sensitivity and field of view of beams, to solve the problem, impedance matching must be applied. In this thesis, MATLAB-HFSS joint simulation is proposed, the circular dependence between active impedances and beamformer coefficients is overcomed, and the feasibilities of several impedance matching methods and MATLAB-HFSS joint simulation are verified by comparison. Third, the influence of system parameters on the performance has been thoroughly studied, and the number, spacing of elements, distance between ground-plane and focal plane are determined. Finally, the PAF system modeling and optimization software is developed for convenience.
Keywords/Search Tags:Radio telescope, Phased array feeds system, System modeling, Effective field of view, Active impedance matching, MATLAB-HFSS joint simulation, Software design
PDF Full Text Request
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