Wideband Electrically Tunable Metamaterial Absorber using Varicap and PIN Diode

We propose a tunable metamaterial absorber (MA) unit equipped with varactor and PIN diodes that is insensitive to polarization, aiming to significantly expand the metamaterial absorbers tunable bandwidth. Based upon hexagon split rings (HSRs), high absorptivity is demonstrated by the unit over a wide range of angles of incidence. By dividing the HSRs into two parts, the absorption frequency may be regularly adjusted within a predefined range via varying the voltage given to the varicap diodes. Through optimization of these parameters, simulation results show that the proposed MA achieves a significantly expanded tunable frequency range of 6.72-8.88 GHz, with a bandwidth of 2.16 GHz.