Integral Equation Formulation for Prediction of Far-Field Radiation Patterns from Near-Field Measurements

An integral equation formulation in which the plane wave spectrum functions of a measured aperture appear as the unknowns is presented. Solutions to this equation are obtained by expanding the unknwons into sampling series and enforcing the equation at a finite number of near-field measurement points. Considerable amount of computer time can be saved by using an aperture-synthesis-technique in the near-field measurements. The method is applied to sectoral horns and good agreement between predicted and direct measured patterns is observed.