Fig. 2

The simulated |S11|, absorption, effective parameters, effective impedances and refractive index from 1 to 30 GHz for the proposed ultra-wideband perfect metamaterial absorber loaded with lumped resistances and the same microstructure without the lumped resistances. a Simulated |S11| results. b Simulated absorption results and effective parameters. c The effective impedances of proposed PMA with lumped resistances and the same microstructure without lumped resistances. d The reflection components of the cross-polarization for the proposed PMA with lumped resistances and the same microstructure without lumped resistances and the refractive index of the presented PMA