| The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) is a Chinese mega-science project which aims to build the largest single dish radio telescope in the world and will greatly promote the development of China’s radio astronomy. Given its multiple simultaneous beam formation, phased array feed (PAF) is widely used as focal array in radio telescope to extend the field-of-view, enhance the survey speed, realize adaptive radio frequency interference suppression and significantly increase the sensitivity of the system. This thesis studies the design of phased array feed based on the requirement of FAST.In this thesis, cosimulation of Matlab and HFSS is compiled firstly to provide a convenient way for antenna layout and system optimization. Secondly, the design requirement of phased array is determined which includes array size, array arrangement, element spacing, number of elements and elements for each beam. Thirdly, under the analysis of the PAF performance index, design idea of element antenna is put forward according to the performance specification for FAST. Then, three kinds of dual-polarized antenna are proposed which are cross-dipole fed by microstrip baluns, magneto-electric dipole and vivaldi antenna respectively. The results show that all the three antennas meet the requirement of FAST. Last but not least, through the comparison of the antenna performance, a conclusion can be drawn that dipole antenna has the excellent properties in the working frequency band and is suitable for the next generation radio telescopes.
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