An Efficient Approach to Extrapolate the Data Falling in the Zone not Covered by Measurements in a Near-Field Spherical Facility

In this paper, a new and efficient technique is developed to estimate the near-field data falling in the blind zone of a near-field spherical facility, i.e., the region not covered by the measurements. The proposed approach is based on the nonredundant sampling representations of the electromagnetic field and makes use of the singular value decomposition method for extrapolating the samples external to the measurement region. This allows a significant reduction of the truncation error occurring in the near field – far field transformation with spherical scanning. Numerical tests assessing the effectiveness of the technique are reported.