| Summary: | 碩士 === 國立成功大學 === 電機工程研究所 === 82 === In order to provide the maximum radiation power over specified
coverage areas, communication satellite antenna are often
required to produce contoured radiation patterns to fit the
desired coverage regions. This has most usually been achieved
by using array-fed parabolic rreflector antennas, with beam
forming networks (BFN) to adjust the amplitude and phase of
each feed, to synthesize desired contoured patterns. However,
the complexity of the BFN will increase the RF loss and the
weight of the satellite platform. This thesis will investigate
the use of a single shaped parabolic reflector antenna and a
single feed for producing a contoured beam to cover the Taiwan
region. First, the characteristics and parameters of the
parabolic reflector antenna will be studied. The geometrical
optics (GO) and physical opticals (PO) method are used to
caculate the far field and antenna gain. The aperture phase
distribution is optimized to synthesize the far-field contoured
pattern with the GO method. The reflector surface is then
determined from the aperture phase distribution. The radiation
performance of the shaped surface is then checked by applying
the PO method. Finally, the analysis and calculation of a
shaped offset-fed parabolic reflector satellite antenna is
performed to produce a contoured beam to cover the Taiwan
region.
|
|---|
