Abstract

This paper focuses on the measurement of the effective magnetic permeability µeff in composite structures built from nonmagnetic materials. Starting from recent studies of magnetism in microstructures, we present the results of a new theoretical and experimental analysis performed at frequencies below the medium frequencies. Mainly, we focus on how "spatial averaging"can affect the estimation of the parameter µeff and show how expressions of µeff derived for a single "unit-cell"configuration find analogy with that relevant to composite structured arrays. Finally, we show how to obtain negative values of µeff for composite materials in the industrial frequency range and make some remarks on how future technologies can impact on the measurement of magnetism in composite materials. © 2009 IEEE.