The thick ring resonators to achieve negative permeability and its left-handed behavior in perpendicular propagation

We experimentally investigated the microwave transmittance properties of the thick ring resonators in a rectangular waveguide for propagation perpendicular to the plane of the ring resonators. Our ring resonators are different from the conventional split ring resonators which have the certain thickness. It is found that a transmission dip occurs at 145GHz and the transmission phase has a shift at the resonance frequency for the thick ring resonators. Furthermore，we calculated the permeability of the thick ring resonators applying bianisotropic composite modeling and found the negative permeability near the resonance transmission dip. We measured the left-handed peak and phase advance by using the thick ring resonators combined with wires which have transmission pass bandwidth of 15GHz and transmission value of -21dB.