| 摘要 |
An antenna device comprised of dielectric elements, the device having an array of parasitic director elements which coherently focuses energy across the parasitic array. The parasitic elements are spaced less than or equal to one wavelength from each other to provide the coherent focusing, with the array thereby acting like an artificial dielectric lens. An optimal spacing or elemental length might include one-eighth (⅛) to one-quarter (¼) wavelength. A plurality of feed elements is associated with the array and provides incident energy thereon. Reflector elements might also be used to further reflect incident energy from a feed element back across the parasitic array. The various elements are switchably selectable via a switching network which might consist of diodes. The parasitic elements form a lens which provides the directionality of the antenna. The switching network, and associated antenna control, provides the ability to dynamically alter the directionality of the antenna without moving parts. A tuning circuit can be associated with each element, with the tuning circuit being used to make certain elements appear electrically longer. The elements will generally be manufactured to be the same. If the tuning circuit grounds a particular element, then it will function as a director element, and can add to the overall gain of the device. If the tuning circuit makes an element electrically longer, then the element will function as a reflector. This device is useful in various applications, including fixed wireless subscriber terminals, base station to remote platform transmissions, radar tracking, and moving platform transmissions. |
