ANTENNA SYSTEM FOR RADIATING DOPPLER CODED PATTERN USING MULTIPLE BEAM ANTENNA

摘要

ANTENNA SYSTEM FOR RADIATING DOPPLER CODED PATTERN USING MULTIPLE BEAM ANTENNA Disclosed is an antenna system for radiating a frequency coded or "Doppler" pattern of wave energy into a region of space using a multiple-beam antenna unit. The system radiates a pattern in which the radiated frequency varies as a function of angular direction from the antenna unit. The system uses an antenna unit capable of radiating simultaneous multiple beams and having a separate input port associated with each beam. The frequency coded pattern is achieved during each of a plurality of successive time periods by supplying wave energy to each of the input ports of the antenna unit from a common source via controllable phase shifters. The phase shifters are controlled such that the wave energy signal supplied to each port of the antenna unit has a phase, measured with respect to the phase of the wave energy signal supplied to the port corresponding to an adjacent antenna beam, which varies during each time period between a predetermined pair of values, with the variation being less than 360.degree. and the sense of the variation being alike for pairs of input ports corresponding to similarly adjacent beams.