An Ultrawideband Miniaturized Metamaterial Absorber in the Ultrahigh-Frequency Range

An ultrawideband miniaturized metamaterial absorber (MMA) in the ultrahigh-frequency (UHF) (0.3-3 GHz) range using a metallic incurved structure is proposed in this letter. Simulated results show that the bandwidth of the MMA with absorptivity more than 90% is 0.8-2.7 GHz with a relative bandwidth over 108%. The size of the unit cell is miniaturized to be only 20 x 20 mm(2), about 0.0136 lambda(2) at the center frequency of 1.75 GHz. Both simulated and experimental results show high absorption for TE and TM polarization over a certain range of incident angles. A simplified equivalent circuit and the current distribution for the MMA are presented to gain an insight into the mechanism to attain broadband absorption. On the aspect of application prospects, the MMA is promising as absorbing elements in UHF-RFID systems and 4G communications.