An efficient technique to lower the error due to the truncation of the scanning region in a bipolar facility

An efficient technique is developed in this article to extrapolate the near-field data falling outside the measurement region in the bipolar scanning. It is based on the nonredundant sampling representations of the electromagnetic field and on the optimal sampling interpolation expansions. The singular value decomposition method is properly employed for estimating the external data. This allows one to reduce in a significant way the truncation error occurring in the nearfield-far-field transformation with bipolar scanning. Numerical examples assessing the effectiveness of the technique are shown.