| 摘要 |
PURPOSE:To cover a service area with simple constitution and a high gain, by constituting a primary reflection system of a primary radiator or the primary radiator and a reflection mirror, projecting one in-plane of a parabora with the main beam of the primary radiator, and projecting another in-plane crossing orthogonally to the plane with the main and sub robes of the radiator. CONSTITUTION:The primary radiation system is constituted of a feed horn 1 or the horn and the reflection mirror 3. A relational equation as t=dh<2>/8#1.(1/Lh+1/S) is established for the horn 1. The dh and Lh represent the aperture diameter and the shaft length of the horn 1, and the S represents a point where a beam of light along the central axis 4 of the horn 1 is reflected on the reflecton mirror 3 and a distance to the center of the aperture. When the (t) is small, the horn 1 is constituted so that a parameter (u) represented as u=d<h>/lambda.sin thetae goes to u>2.5. The thetae represents the half value of the illuminating angle of a beam. In a plane (z x), electric field distribution on an aperture plane in the plane (z x) of the reflection mirror 3 coincides with that shown in figure by the reflection of radiating beams 2a and 2b. When a beam (c) in a main robe area in a plane (y z) is reflected, the electric field distribution on the aperture plane in the (y z) coincides with that shown in figure. Therefore, it is possible to obtain a rectangular beam which forms a dibeam by the beams 2a and 2b.
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