Reduction in quantization lobes due to digital phase shifters for phased array radars

A new method to reduce quantization lobes for phased array antennas is proposed. Quantization lobes come to exist in far-field radiation patterns because phase errors occur due to digital phase shifters that quantize the ideal phase shifts needed to steer antenna beams. The proposed method is particularly useful for radar systems and makes it possible to reduce not only the peak quantization-lobe level but also the average level, which has not been possible with conventional methods. A possible implementation of the method in an actual radar system is presented. The method´s validity was verified through simulations of radiation patterns of a linear array antenna. It was found that the same performance exhibited by a phased array antenna with higher-bit phase shifters can be realized with lower-bit phase shifters at the expense of time.