What I have found is for any metamaterial absorber, if the effective permittivity is negative at the resonant frequency, then the resonance is plasmonic, and if the effective permeability is negative at the resonant frequency, then the resonance is of the magnetic type. What are the reasons behind this? Again, from the current distribution, it can be decided that the structure shows either electric dipole or magnetic dipole resonance. What is the relationship between these types of resonances in a metamaterial absorber?