Design and measurement of negative permeability metamaterials made from conductor-coated high-index dielectric inclusions

We investigate metal-dielectric inclusions that provide highly resonant permeability. These inclusions are made of high-index slabs with conductor plating on some faces. Microwave measurements are performed on several types of gratings made from these patterns. Broad band experiments are carried using a coaxial cell. Negative permeability levels lower than −20 have been observed in the GHz range, along with loss levels as low as 0.09 at μ′ = −1. We show that among the different theoretical approaches that are adequate to describe these materials, the field summation approach provides a very straightforward way to derive the effective permeability. The simple analytical expression of the permeability is in excellent agreement with the experiments. These inclusions are shown to be attractive both from the technological and the intrinsic performance point of view for metamaterial manufacturing. The effects of inclusion imperfections and finite thickness are discussed.