Title :
Complex-Point Dipole Formulation of Probe-Corrected Cylindrical and Spherical Near-Field Scanning of Electromagnetic Fields
Author :
Hansen, Thorkild B.
Author_Institution :
Seknion Inc., Boston, MA
fDate :
3/1/2009 12:00:00 AM
Abstract :
A probe-corrected electromagnetic theory based on complex-point dipoles is presented for computing the field of an arbitrary source of finite extent (for example a test antenna) from measurements of its near field on a cylindrical or spherical scanning surface. By representing the probe with complex-point dipoles, probe correction is achieved by simple factors that involve Hankel functions evaluated at complex points. Only four complex-point dipoles are needed to represent a typical precision probe used in near-field measurements. The theory uses neither translation and rotation theorems nor differential operators. One disadvantage of the theory is that it employs nonlinear optimization to determine the parameters of the probe model. The complex-point dipole representation of the probe makes realistic simulations of near-field scanning systems straightforward. The cylindrical theory is validated through a numerical example. The spherical theory is validated by experimental data.
Keywords :
dipole antennas; electromagnetic field theory; Hankel functions; complex-point dipole formulation; cylindrical theory; electromagnetic fields; probe-corrected cylindrical scanning; probe-corrected electromagnetic theory; spherical near-field scanning; Antenna measurements; Antenna theory; Computational modeling; Dipole antennas; Electromagnetic fields; Electromagnetic measurements; Electromagnetic scattering; Probes; Testing; Transducers; Complex-point dipoles; cylindrical scanning; near-field measurements; probe correction; spherical scanning;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2009.2013438