Low-Loss Magnetic Metamaterial at THz Frequencies by Suppressing Radiation Losses

We propose an effective way to reduce losses of the magnetic metamaterial by suppressing radiation losses. The numerical simulations unveil that the losses reduction of the magnetic metamaterial is achieved by placing a split ring resonator (SRR), twisted at an angle of 180° with respect to the existing SRR owing to suppression of the radiation damping caused by residual currents in the SRR metamaterial. This leads to a remarkable increase in the figure of merit (FOM) of the proposed system compared to the single SRR. The dependence relationship between the loss property of the proposed system and the coupling interaction is also theoretically investigated in detail. Results show that when the distance between SRRs changes, the negative permeability effect and the FOM value correspondingly change due to the different cancellation of residual currents in each SRR. On the other hand, a different SRR configuration that the dielectric medium is added to the SRR metamaterial is conceived. This leads to in a finite bandwidth deviated from the resonance frequency where the SRR's loss performance is dramatically improved due to suppression of the radiation losses. These results open up new prospects for study of the unique effects associated with low-loss and negative index materials at THz frequencies.