\input zb-basic \input zb-ioport \iteman{io-port 05226219} \itemau{Mahani, Z.; Hakim, A.; Ziyyat, A.} \itemti{Spheroidal near-far-field transformation.} \itemso{Int. J. Math. Stat. 2, No. S08, 73-93 (2008).} \itemab This work presents a Near Field/Far Field Transformation (NF-FF) into spheroidal coordinates systems. This transformation is used for the characterization of antennas and radiant structures. It allows the evaluation of the far Field starting from the taking of the Field in closed surface on a spheroid enclosing all radiating sources, whether it is prolate or oblate. The transformation suggested is based on a modal development into spheroidal waves. The vectorial wave equation not admitting an orthogonal solution in spheroidal coordinates, the method presented uses the rectangular components of the Field in the scalar wave equation, but expressed in spheroidal coordinates. \itemrv{Messoud A. Efendiev (M\"unchen)} \itemcc{} \itemut{modal development; spheroidal coordinates; antennas measurement; near field; far field transformation} \itemli{} \end