Calculation of a Far Field Near Field Transformation

Last year we presented [1] during IEEE-APS 2012. In this article we reminded the principle of the Near Fear Far Field Transformation (NFFFT) (that we presented during IEEE-APS 2009) and quantified the degree of approximation of this Transformation. The strength of this NFFFT is to allow the calculation of Far Field from the knowledge of Near Field. Yet, in some operational cases, the source of radiation cannot be considered as located at an infinite distance but only at a finite distance D. In these conditions it would be more relevant to work in "Near Field at the distance D" unstead of working in "Far Field". In the case where the lighted target may be assumed as being constituted by scatterers, this paper demonstrates the possibility to calculate "Near Field at the distance D" RCS from the knowledge of Far Field RCS, while giving eventually the principle of the Far Field Near Field Transformation (FFNFT).