| 摘要 |
A wide-band feed for a reflector antenna that provides a sum and a difference radiation pattern for tracking and for the transmission or reception of data. The feed utilizes two coaxially located, coaxial waveguides. The inner coaxial waveguide supports propagation of the TE11 mode and produces a sum radiation pattern. The outer coaxial waveguide supports propagation of the TE21 mode and produces a difference radiation pattern. The dimensions of the inner and outer waveguides are selected such that the dispersions of the TE11 mode in the inner coaxial waveguide and the TE21 mode in the outer coaxial waveguide are the same. Coaxial chokes located near the open ends of the wave guide modify the impedance match to free space of the fields within the waveguides and modify the radiation patterns generated by the waveguides. Probes within the waveguides generate the respective modes. Fins located in proximity to the probes operate as cutoff waveguides which terminate the probe end of the waveguides and which modify the impedance of the probes.
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