A spherical multibeam antenna

One of the most difficult problems in scanning antenna technology is the realization wide angle scanning. Typical planar phased arrays exhibit poor performance at large scan angle (beyond approximately 45/spl deg/) due to natural limitations: scan loss and grating lobes which generate high sidelobes. Furthermore, planar phased arrays architectures using phase shifters, or true time delay phasing, have low efficiency, due to losses associated with the dielectric and ferrite materials. The wide-band properties of planar phased arrays are also quite limited if high beam-efficiency and high efficiency overall are required. To these days, some investigation has been done in the field of 3D scanning antennas. While improved in the wide angle scan capability, due to their complexity, the architectures proposed so far, seem to be quite unattractive. The architecture proposed below seems to overcome the difficulties mentioned above, and offers high efficiency, with wide-angle scanning capability, and with (almost) identical beams regardless of the scanning angle. The architecture proposed consists of a Single-K spherical lens fed by a spherical array of waveguides.