Hardpoint Demonstration Array Radar

The project HAPDAR (HArd Point Demonstration Array Radar) is a part of Project Defender, sponsored by the Advanced Research Projects Agency, Department of Defense, under ARPA Order Number 516 and contracted through the Army Missile Command. An attractive practical phased array radar system design is described in this paper. The HAPDAR radar is a multimode multifunction system capable of electronic scanning a pencil beam in two dimensions. The principal design feature is the TACOL (Thinned Aperture Computed Lens) approach to the antenna design. The lens is a passive array capable of collimating the beam and steering it in the desired direction. A single klystron transmitted illuminates the lens and a standard monopulse feed is used to extract angular errors. The design principles of TACOL are discussed and a complete description of the radar is presented.