3-D Thin-Wire FDTD Approach for Resistively Loaded Cylindrical Antennas Fed by Coaxial Lines

• Published in: IEEE transactions on antennas and propagation Vol. 58; no. 12; pp. 4095 - 4099
• Main Authors: HYUN, Seung-Yeup, KIM, Se-Yun
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna feeds; Antennas; Applied sciences; Approximation; Cartesian; Coordinate transformations; Cylindrical antennas; Exact sciences and technology; Finite difference method; Finite difference methods; Finite difference time domain method; Finite-difference time-domain (FDTD) methods; Loaded antennas; Mathematical analysis; Radiocommunications; resistive loadings; Resistors; Studies; Telecommunications; Telecommunications and information theory; thin wires; Time domain analysis; Near field; Cylindrical antenna; Finite difference time-domain analysis; Quasi static theory; Cartesian coordinate; Numerical method; Coaxial line; Cylindrical shape; Finite-difference time-domain (FDTD) methods; thin wires; Accuracy; resistive loadings; Cylindrical coordinate; Antenna feeds; Numerical simulation; loaded antennas; Resistor; Piecewise linearization
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2010.2078461

For the efficient finite-difference time-domain (FDTD) analysis of electrically thin and resistively loaded cylindrical antennas, the 2-D cylindrical thin-wire approach with circular symmetry is extended to the 3-D Cartesian FDTD with non-cubic cells for asymmetric cases. The axial geometry of the antenna is represented as a set of piecewise-linear lumped resistors. And the near fields around the antenna and the coaxial feed aperture are approximated to the quasi-static fields with the cylindrical behavior. From the cylindrical-to-Cartesian coordinate transformation of the quasi-static fields and the contour-path integration along FDTD unit cells in the vicinity of the antenna and its feed, the 3-D Cartesian FDTD equations are derived. These equations may correspond to a full coarse-grid FDTD approach with the equivalent corrections. For some numerical examples, the proposed approach provides comparable accuracy to the reference data with fine-grid resolution. Effects of the cell size and the resistive loading profile are investigated numerically.