Investigation of a Near-Perfect Quad-Band Polarization-Insensitive Metamaterial Absorber Based on Dual-T Circular Shaped Resonator Array Designed on a Silicon Substrate for C-, X- and Ku-bands Applications

Multi-band metamaterial absorbers (MMAs) are increasingly becoming main devices for many electrical systems. Optimizing the electromagnetic qualities of this type of absorber in the microwave regime is a relatively complex operation. In this paper a quad-band metamaterial absorber is provided for applications covering the microwave C-, X- and Ku- frequency bands. The proposed MMA is based on (8 x 8) array basic cells. Each cell is formed by a split-ring metamaterial resonator (SRR), the chosen shape for the SRR is the circular dual-T (DT-SRR) interlinked with the rectangular ring. The DT-SRR is etched on the upper side of the Silicon substrate with relative electrical permittivity of 11.7. On the bottom side of the same substrate, a ground plane for full copper surface is printed to prevent transmission. The basic cell has the electrical dimensions of the order of (0.385 lambda(0) x 0.385 lambda(0) x 0.032 lambda(0)) where lambda(0) is calculated at the lowest operating frequency of 6.43 GHz in the C-band. The electromagnetic qualities of our MMA are expired by the behavior of each basic cell which represents a left hand medium and a negative permeability (mu < 0) for magnetic resonances at the frequencies 6.43, 9.10, 11.86 and 14.67 GHz. The obtained results simulations performed by the High-Frequency Structure Simulator (HFSS) computer show an insensitive-polarization dual-band behavior for our proposed MMA. The spectral responses of the proposed absorber cover the C-, X- and Ku-bands for important absorption coefficients of the order of 89.40, 99.66, 99.10 and 95.22%.