Reconstruction of Equivalent Currents Distribution Over Arbitrary Three-Dimensional Surfaces Based on Integral Equation Algorithms

• Published in: IEEE transactions on antennas and propagation Vol. 55; no. 12; pp. 3460 - 3468
• Main Authors: Alvarez, Y., Las-Heras, F., Pino, M.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antenna measurements; Antenna radiation patterns; Antennas; Apertures; Applied sciences; Current distribution; Equivalence principle; equivalent sources; Exact sciences and technology; Geometry; Integral equations; inverse radiation problem; Magnetic domains; Magnetic field measurement; near-field far-field transformation (NF-FF); Near-field radiation pattern; Radiocommunications; Studies; Surface reconstruction; Telecommunications; Telecommunications and information theory; Near field; Horn antenna; Equivalent current; near-field far-field transformation (NF-FF); Far field; Iterative method; inverse radiation problem; Algorithm; Equivalence principle; Inverse problem; Regularization method; equivalent sources; integral equations; Three dimensional model; Electric field; Current distribution; Integral equation; Diagnostic aid
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2007.910316

A technique for the determination of the equivalent currents distribution from a known radiated field is described. This Inverse Radiation Problem is solved through an Integral Equation algorithm that allows the characterization of antennas of complex geometry both for near field to far field (NF-FF) transformation purposes as well as for diagnostic tasks. The algorithm is based on the representation of the radiating structure by means of a set of equivalent currents over a three-dimensional (3D) surface that can be fitted to the arbitrary geometry of the antenna. The innovative formulation uses an integral equation involving the electric field due to the currents tangential components to the represented antenna 3D surface. For that purpose, both the magnetic and electric equivalent currents are considered in the integral equations. Regularization techniques are also introduced to improve the convergence of the proposed iterative solution. The paper concludes with several results related to the practical verification of the Equivalence Principle and the characterization of a horn antenna.