Abstract:A quantization error caused by digital amplitude adjusters and phase shifters on array antennas leads to deterioration of directional patterns. Especially, it affects null depth and null angle. In this paper, reduction method of quantization error using auxiliary antenna on array antenna is proposed. One element in the array antenna is operated as auxiliary antenna to reduce the quantization error of other array elements. The null accuracy is improved by the effect of the auxiliary antenna, therefore, the deeper null is formed in correct angle. The validity of the proposed method is shown through numerical simulation.