Advances in Radio Science www.adv-radio-sci.net 1684-9965 1684-9973 7 Kleinheubacher Berichte 2008 2009 10.5194/ars-7-17-2009 http://www.adv-radio-sci.net/7/17/2009/ http://www.adv-radio-sci.net/7/17/2009/ars-7-17-2009.html http://www.adv-radio-sci.net/7/17/2009/ars-7-17-2009.pdf 17 22 2009-05-18 Hybrid multilevel plane wave based near-field far-field transformation utilising combined near- and far-field translations C. H. Schmidt schmidt@ihf.uni-stuttgart.de T. F. Eibert Institute of Radio Frequency Technology, Universität Stuttgart, Germany Lehrstuhl für Hochfrequenztechnik, Technische Universität München, Germany The radiation of large antennas and those operating at low frequencies can be determined efficiently by near-field measurement techniques and a subsequent near-field far-field transformation. Various approaches and algorithms have been researched but for electrically large antennas and irregular measurement contours advanced algorithms with low computation complexity are required. In this paper an algorithm employing plane waves as equivalent sources and utilising efficient diagonal translation operators is presented. The efficiency is further enhanced using simple far-field translations in combination with the expensive near-field translations. In this way a low complexity near-field transformation is achieved, which works for arbitrary sample point distributions and incorporates a full probe correction without increasing the complexity. Abramowitz, M. and Stegun, I E.: Handbook of Mathematical Functions, Dover Publications, Inc., New York, 9th edn., 1972. Chew, W C., Jin, J M., Michielssen, E., and Song, J M.: Fast and Efficient Algorithms in Computational Electromagnetics, Artech House, Inc., 2001. Chew, W C., Cui, T J., and Song, J M.: A FAFFA-MLFMA Algorithm for Electromagnetic Scattering, IEEE Trans. Antennas Propag., 50, 1641–1649, 2002. Coifman, R., Rokhlin, V., and Wandzura, S.: The Fast Multipole Method for the Wave Equation: A Pedestrian Prescription, IEEE Antennas and Propag. Mag., 35, 7–12, 1993. FEKO Suite 5.4, http://www.feko.info, access: 24 February 2009. Hansen, J E.: Spherical Near-Field Antenna Measurements, IEE Electromagnetic Wave Series 26, Exeter, UK, 1988. Kerns, D M.: Plane-Wave Scattering-Matrix Theory of Antennas and Antenna-Antenna Interactions, National Bureau of Standards, Boulder CO, 1981. Saad, Y.: Iterative Methods for Sparse Linear Systems, Society for Industrial and Applied Mathematics, 2nd edn., 2003. Sarkar, T K. and Taaghol, A.: Near-Field to Near/Far-Field Transformation for Arbitrary Near-Field Geometry Utilizing an Equivalent Current and MoM, IEEE Trans. Antennas Propag., 47, 566–573, 1999. Schmidt, C H. and Eibert, T F.: Multilevel Fast Near-Field Far-Field Transformation for Electrically Large Antennas, IEEE AP-S International Symposium, San Diego, USA, 2008. Schmidt, C H., Leibfritz, M M., and Eibert, T F.: Fully Probe-Corrected Near-Field Far-Field Transformation Employing Plane Wave Expansion and Diagonal Translation Operators, IEEE Trans. Antennas Propag., 56, 737–746, 2008. Tzoulis, A. and Eibert, T F.: Efficient Electromagnetic Near-Field Computation by the Multilevel Fast Multipole Method Employing Mixed Near-Field/Far-Field Translations, IEEE Antennas Wireless Propag. Lett., 4, 449–452, 2005. Yaghjian, A D.: An Overview of Near-Field Antenna Measurements, IEEE Trans. Antennas Propag., 34, 30–45, 1986.