Browsing by Author "Cheng, Po-Kai"

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    NeXtRAD antenna design: X-Band dual polarised conical horn antenna
    (2016) Cheng, Po-Kai; Murgu, Alexandru; Downing, B J; Inggs, Michael
    The purpose of the dissertation is to investigate a design and implementation of a dual polarised X-band antenna. The desired specifications include a centre frequency of 8.5 GHzand a 10_ azimuth-half power beam width in both vertical and horizontal polarisations. Other requirements include peak power handling of 400 W over a 50 MHz instantaneous bandwidth and the facility to be mounted on a standard tripod. The dissertation begins by introducing NeXtRAD, a radar project developed jointly by UCL and UCT, outlines the objective of the study and lists all the requirements to be achieved. After considering several types of antenna, horn antenna has been the most practical when trying to meet project requirements. Two of the horn antennas examined here have been the square and conical horn antennas using square and circular waveguides respectively. Each of these waveguides support dual polarisation as they provide a symmetrical structure in two orthogonal planes of polarisation. The square waveguide is flared into a square horn whereas the circular waveguide is flared into a conical horn to increase the gain and reduce the half-power beamwidth to the required angle.