| Three dimensional Fresnel antennas |
It was shown that there are free parameters in the usual design of three dimensional Fresnel zone plates (3D FZP), lenses and antennas. These novel free parameters allow controlling the beam pattern of diffractive antennas. The diffraction antennas can form a directivity pattern of a quite arbitrary shape.
In this kind of antennas it is possible to provide scanning by directivity pattern in the range no less than ±20°…±30° by displacing a radiation receiver, or to receive simultaneously signals from several users in this sector. The use of diffractive lenses on non-plane surfaces as antennas makes it possible to increase an equisignal zone of the scanning sector of a radiation pattern. Such antennas allow their or to receive simultaneous use as a radome to provide ambient protection of the equipment. In addition, the application of antennas with radiation focusing off the optic axis makes it possible to avoid radiation screening by a receiver and decrease noise of the antenna system. |