Study of the influence of a layer of metamaterial over the performances of a coplanar isolator.
Résumé
Isolators with thin layers of magnetic material need to maximise the effect between the fields and the active layer, because of the small thickness of the material. The solution we explore to confine the fields in the magnetic layer is to put a layer of dielectric-resonant-like metamaterial under that layer. A theoretical study has shown that such layers with strong permittivity are of interest in that case and the purpose of that paper is to study the practical realization of such a device. Our layer of resonating metamaterial consists of a grid of S particles. In a first step we studied the metamaterial in free space, unlighted by a plane wave, in order to evaluate its degree of anisotropy at frequencies around the resonance. The S particle is square, not round, and that implies a stronger anisotropy of the material. Secondly, we studied the whole coplanar structure with the metamaterial, numerically with HFSS, to check that the behaviour in the guided propagation follows the one in free space conditions, i.e. that the conditions are nearby the ones of a homogeneous material with resonant permittivity, and that numerical study is validated with measurements of the coplanar line with metamaterial.