Procedure to Calculate the Inductance of a Circular Loop Near a Metal Plate

摘要

This paper describes the influence of metallic objects on the inductance as a function of the separation distance. We focus our attention on the benchmark configuration of a circular loop antenna near an infinite conducting plate. We consider the quasi-static approach, thus with a constant current distribution over the entire loop. The results are obtained by numerical integration and the accuracy of the numerical integration procedure is verified for a circular loop antenna in free space, for which a closed analytical solution exists. The results are particularly interesting in the domain of low frequency and high frequency Radio Frequency IDentification, where mutual influence of multiple reader antennas is often suppressed by means of a metallic shielding, which results in an important decrease of the readout distance and a detuning of every reader antenna.