| 摘要 |
<p>In a primary radiator in which a radiation section of a dielectric feeder (2) is made to protrude from an opening of a waveguide (1), in order to reduce side lobes and improved receiving efficiency, the opening is provided at one end thereof, the dielectric feeder is held inside the waveguide, and the radiation section of the dielectric feeder is made to protrude from the opening. An annular wall (3) which is formed so as to have a bottom is provided in such a manner as to surround the opening of the waveguide, the depth dimension of the annular wall is set to approximately 1/4 of the wavelength of the radio waves, and the width dimension of the bottom surface of the annular wall is set to approximately 1/6 to 1/10 of the wavelength of the radio waves. Consequently, the phases of a surface current which flows on the outer surface of the waveguide from the opening toward the bottom surface of the annular wall and a surface current which flows on the inner surface of the annular wall from the bottom surface of the annular wall toward the opening end are opposite and cancel each other. As a result, the side lobes are greatly reduced, and the gain of the main lobe is increased, making it possible to efficiently receive radio waves from the satellite. <IMAGE></p> |
