Influence of the dielectric-spacer thickness on the dual-band metamaterial absorber

A combined element method is proposed which can be applied in designing dual-band metamaterial absorber. A dual-band metamaterial absorber is presented by introducing two elements in one unit cell. We first give two absorptive peaks which are verified by experiments. Two absorption peaks appear near 9.02 GHz and 11.85 GHz with magnitude of 99.3% and 99.4%, respectively. Second, current and field distribution is given to better understand the physical mechanism of the absorption. What is worth noting, the power scattered by the electric and magnetic dipole is also displayed which can help us solve some obscure problems. At last, we investigated the effects of the dielectric-spacer thickness on the absorption. It is found that the thickness of the dielectric spacer provide sensitive effects on the magnetic resonance.