| 摘要 |
<p>An antenna horn is formed from a waveguide (2). This contains a ferrite rod (8) within a dielectric sleeve (12). A coil (16) is wound around the outside of the waveguide (2). The arrangement is such that the horn is selectably responsive to signals polarized in a first direction and in a second direction substantially perpendicular to the first direction, both directions being perpendicular to the axis of the horn [longitudinal axis of the ferrite rod (8)]. The selection is made by setting the current in the coil to either a first or a second predetermined value respectively.</p> |
