An Accurate and Fast Method to Determine Antenna Directivity in Near-field Scanning Measurement

Near-filed (NF) scanning measurement is an effective way to evaluate the antenna radiation characteristics, among which antenna directivity is an important parameter for radar systems. In this paper, an accurate and fast method is proposed to determine the antenna directivity based on NF scanning measurement. The antenna far-field (FF) patterns are firstly produced by extrapolating the planar NF data obtained in NF scanning, then the antenna directivity can be estimated using the pattern integral method. Different from the existing methods, an integral transformation method is proposed to calculate the pattern integral, which deals with the FF responses in the wavenumber domain directly, avoiding the complex interpolation operation in angle domain. The proposed method is verified with both simulated data and experimental data. The results indicate that the proposed method can significantly promote the computation efficiency and estimation accuracy, which is superior to the existing methods.