Discrete lenses for multibeam applications

A spherical discrete lens antenna based on the back-to-back combination of two choked-horn antennae arrays interconnected through smooth waveguides sections implementing the spherical phasing law, has been designed, simulated and fabricated. The spherical phasing law of the lens converts the incoming spherical phase front, from a small feeder placed at the focal plane, into a plane phase front. Depending on the feeder position at the focal plane (the perpendicular plane to the len´s axis containing the focal point) the beam is pointed in different directions. The minimum angular distance between two beams is directly related to the minimum distance between two adjacent positions of low directive and, therefore, small feeders. The selected implementation offers several advantages compared to an actually curved lens, such as the simplification of the fabrication, the constant physical length of the phasing waveguides and the dispersion of the back-scattered power, reducing significantly the coupling between feeders.