| 摘要 |
A parabolic reflector antenna, designed to discriminate between incoming and outgoing waves having mutually orthogonal planes of polarization, has a ratio R between focal distance f and diameter D which, for optimum efficiency and cross-polarization decoupling, lies between 0.46 and 0.5 and operation in the TE11 mode and above 0.6 for operation in the dual TE11+TM11 mode. An associated feed, in the shape of a slightly tapering horn of circular cross-section connected to a waveguide of square cross-section, has a relative aperture alpha , defined as the ratio between its aperture radius r and the wavelength lambda o at the center of the operating frequency band, which in the first instance ranges between 0.52 and 0.6 and in the second instance is given by kR+h with k APPROX 1 and h between about 0.1 and 0.15.
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