Development of X-band space feed phased array antenna system

An electronically controlled phased-array antenna system using space feed through a lens array is presented. The aperture excitations of the array elements for monopulse sum and difference patterns are illuminated by a multimode feed horn which provides an efficient aperture illumination with less spillover loss than the conventional multiple feed horn does. The radiating element couples the pickup element through a dual-mode reciprocal ferrite phase shifter. The beam position in space is electronically steered by a beam-steering controller. The antenna system consists of 496 radiators spread over a circular aperture of 24-cm radius. The focal ratio is set to be 0.61. A triangular lattice grid is adopted to optimize the aperture efficiency. Results of simulation and measured far-field patterns are presented.<>