| 摘要 |
A method and a device are disclosed for the generation of a surface, the reflection phase gradient of which will be varied by means of a controllable static electric field. The present solution takes into account, instead of mainly the transmissive properties, also the reflection properties of an arrangement comprising a ferroelectric material. Such a reflecting surface may contribute to an entire antenna aperture, a portion of an antenna aperture or an element in a conventional array aperture. In a general case N lobes and M nulls are to be controlled at the same time. In such a case the surface will preferably be designed as a curved surface, for instance a rotation symmetric parabola, while in other cases the reflector element may be designed just as a plane mirror. An antenna comprising such a reflector element of ferroelectric material can also form a polarization twisting Cassegrain antenna with a flat or curved main reflector element. The reflector element in a typical embodiment consists of a plate (50) of a material presenting ferroelectric properties and provided on each side with electromagnetically transparent highly resistive films (24, 34) each fed by means of a pair of parallel highly conducive edge wires (22, 23 and 32, 33). By applying a controllable voltage across each pair wires the lobe of the continuous aperture scanning reflector antenna can be controlled in a plane X-Z by a voltage Ux and in a plane Y-Z by a voltage Uy. |
