| 摘要 |
An antenna assembly wherein the direction of a beam of radio frequency energy may be changed by combining the effects of a mechanically movable reflector and an electromagnetic lens is disclosed. In the preferred embodiment the antenna arrangement includes a corporate monopulse feed arranged to produce a linearly polarized divergent beam which is first reflected from a linearly polarized paraboloid to direct a convergent beam toward a mechanically rotatable polarization-twisting reflector. A selected portion of a spherical electromagnetic lens arrangement is illuminated by the still convergent beam from the latter reflector, such lens then determining the direction of the beam finally propagated in free space. The relative positions of the corporate monopulse feed, the linearly polarized paraboloid, the mechanically rotatable polarization-twisting reflector and the characteristics of the spherical electromagnetic lens arrangement are selected so that, for a given antenna assembly for electromagnetic energy of a given frequency, the linearly polarized divergent beam from the corporate monopulse feed is converted to a substantially collimated beam in free space.
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