Calculation of the Fresnel region fields based upon the Wilcox expansion theorem of electromagnetic fields

Typically, the integral representations of the Fresnel fields of antennas and scatterers, in terms of the equivalent sources for these fields, are time consuming to evaluate. However, these integrals do become manageable as the point of observation recedes to infinity. The authors exploit this fact and show how the Fresnel region fields can be constructed by processing the far fields using an algorithm for far-field-to-Fresnel-field transformation based upon the Wilcox expansion theorem. To verify the accuracy of the proposed procedure, a number of test cases have been investigated.<>