| 摘要 |
PURPOSE:To improve the factor of elliptical polarization of an antenna by providing a load absorbing only the polarized wave component due to a reflected wave sent from a sub-reflecting mirror to a polarizer used for a primary radiator of a Cassegrain antenna. CONSTITUTION:The 4GHz band of a reflected wave generated by the Cassegrain antenna sub-reflecting mirror is a left-handed circularly polarized wave and the 6 GHz band is a right-handed circularly polarized wave, and when the reflected wave is returned to the polarizer through a circularly polarized wave generator, the wave in the 4GHz band becomes a vertically polarized wave and the wave in the 6GHz band becomes a horizontally polarized wave. The vertically polarized wave in the 4GHz band enters the left side of a circular waveguide 20, because no magnetic field component exists in the lower guide wall the wave is not coupled to a slit of a branching waveguide 23 but coupled to a coupling loop 29 and passes through a coaxial low filter 30 and is absorbed in a resistive terminator 31. On the other hand, the horizontally polarized wave in the 6GHz band is not coupled by the branching waveguide 23 and the absorbing load 24 because of filters 27, 30 but absorbed in a resistance plate 33 in the 2nd circular waveguide 22. |
