Effect of loss and coupling on the resonance of metamaterial: An equivalent circuit approach

In this work we establish an equivalent circuit model to analyze the resonace of the metamaterial considering the loss of the unit cell and coupling effect between them. From this model, we find that metamaterial can be divided into three categories: weak, critical and strong couplings, depending on the values of the loss and coupling strength, where the different resonant properties are presented. The physical reason of the division is whether the loss in each unit cell can be offset by energy coupling from the adjunct unit cells. Full-wave electromagnetic simulations have also been carried out to verify the equivalent circuit analysis. Our circuit analysis provides a simple and effective way to understand the coupling of the metamaterial and gives guidance for the analysis and design of the metamaterial.