Prediction of far-field from under-sampled near-field data based on cubic spline interpolation in spherical near-field antenna measurements

A novel method to predict far-field from under-sampled near-field data which is based on cubic spline interpolation (spline) in spherical near-field antenna is proposed in this paper. Spline method is utilized to the under-sampled near-field data and then the spherical wave expansion is used to calculate the far-field pattern. Simulation results show that the higher far-field pattern accuracy can be obtained by adopting the proposed spline method compared with the piecewise-cubic Hermite interpolation (pchip) method. Hence, the proposed spline method has more advantages and practicability in the spherical near-field measurements of under sampling.