Theoretical and experimental investigations of planar metamaterials at radio frequencies for magnetic resonance imaging

Left-Handed Materials (LHMs) are artificial structures which present a negative permittivity epsiv and a negative permeability mu simultaneously. They can be realized using a periodic disposition of metallic rods and split rings resonators (SRRs). One of the most interesting properties of these LHMs is the emergence of negative refraction. This property may be explored for several applications at microwaves. The aim of this work is to study theoretically and experimentally some properties of metamaterials at radio-frequencies using planar and compact structures. The choice of the radio-frequency range is related to several applications such as compact antennas with high directivity or magnetic resonance imaging. We investigate the properties of spiral resonators between 100 MHz and 500 MHz, either coupled to strip lines to form a left handed (LH) metamaterial, or disposed into a 3x3 array to form a Single Negative (SNG) metamaterial.