Spinning grating antenna for MMW imaging

MMW Scanning Antenna remains one of the most challenging components in the imaging radar design. Electronically steered antennas require sophisticated fabrication and become prohibitively expensive if a large array is considered. Mechanically scanning antennas typically involve one or more hinged parts (lenses, mirrors or feeds). In operation they experience mechanical acceleration and forces that sharply limit scanning rate. We present test results of a recently developed MMW scanning antenna that is capable of providing a fast linear scan while requiring only continuous constant speed rotation. Two antennas applicable to the aircraft autonomous landing and automotive collision warning systems have been developed. They are characterized by simple design and low fabrication cost. Other antennas modifications based on the evanescent coupling principle are proposed to facilitate various radar functions.