| 摘要 |
<p>A feed horn (3) comprises a waveguide (5) having an opening portion of a circular section and a horn portion (4) having an elliptic open end (6) and connected to the waveguide. On an inner slant peripheral surface of the horn portion are formed a plurality of elliptic grooves (7) at radial intervals axially from a front end of the horn portion toward the waveguide, as well as a plurality of axially extending elliptic ridges partitioned by the grooves. Tip ends of the ridges are formed with a difference in height so as to approach the waveguide successively as they are positioned radially centrally. The horn portion (4) has an elliptic tapered portion (9) which expands in a horn shape from one axial end (4a) of the horn portion (4) toward a front end (4b) of the elliptic open end (6), namely, the axial front end of the horn portion. <IMAGE></p> |
