Validation of Computational Models of Wireless Devices by Comparing Measured and Simulated One-port Quantities due to Near-field Perturbations

The measurement and numerical prediction of the electromagnetic (EM) field distribution (and/or its statistical behavior) of radiating elements (e.g., various antennas) is of considerable interest nowadays. Application examples are, for example, the prediction of specific absorption rates of communication devices or the inspection of the statistical properties of EM field in reverberation chambers (RC). In this paper a formula is derived that provides the connection between the actual field distribution in a small volume and the input impedance of the antenna. Based on this relation a quantity being in approximate relation with the power density of a dedicated small volume can be measured. The derived formulation is also investigated from the numerical point of view by comparing the prediction of various numerical models. The numerical studies done here give guidelines to the design of experiments that can give robust tests of the EM distribution in the studied environment.