  It is shown that artificial magnetism with relatively large frequency
bandwidth can be obtained from periodic arrangements of dielectric rings.
Combined with dielectric rods, dielectric rings can provide 3D isotropic
left-handed metamaterials being an advantageous alternative to metallic split
ring resonators and/or metallic wires when un-detectability by low frequency
external magnetic fields is desired. Furthermore it is shown that dielectric
rings can be also combined with natural plasma-like media to obtain a
left-handed metamaterial.
