Performance of Different Functionals for Interpolation/Extrapolation of Near/Far‐Field Data

Chebyshev polynomials are used to extract from the data collected under non‐anechoic environment a radiation pattern for the same antenna radiating in free space conditions. The Cauchy method based on Gegenbauer polynomials is presented for antenna near‐field extrapolation and the far‐field estimation. Some numerical results are given to demonstrate the applicability of the proposed scheme in antenna near‐field extrapolation and far‐field estimation. Total least square (TLS) and singular value decomposition also suppress partially the effects of noise in the known data for extrapolation. The TLS solution for best data fitting shows an excellent performance for minimizing errors of interpolation in. TLS can also work well for extrapolating missing data on a small interval, which is quite similar to an interpolation problem with several sample points removed. However, an interesting result of zenith‐directed reflector antenna configuration is that the hole was able to be expanded significantly without increasing the error of the interpolation.