Validation of Numerical Models of Portable Wireless Devices for Near-Field Simulation

The major contribution of the paper is a theoretical proof of the equivalence between two approaches of near-field validation techniques for the numerical models of personal wireless communication devices. The current validation practice is to compare measured and computed electromagnetic field or specific absorption rate distributions. A new validation technique introduced by the authors recently compared measured and computed antenna input-impedance changes while the near field is systematically perturbed by a dielectric control object. The proof of the equivalence is based on two novel formulas derived here: a reaction impedance-change formula, and an error formula that establishes a quantitative relationship between the errors of the impedance changes and the near-field values. The equivalence of the two validation techniques is verified experimentally too by comparing measurements and computations for a planar-inverted F antenna. By performing numerical experiments for two types of printed-circuit board antennas, it is also proved here the first time that the new validation technique is feasible even if the geometric and material properties of the control object are such that the Born approximation can be introduced in the impedance-change formula.