A Broadband Terahertz Metamaterial Absorber Based on Two Circular Split Rings

We present a broadband terahertz metamaterial absorber, of which the unit cell is made up of two cirular split rings, a dielectric substrate and a metallic ground. The simulation results show that the absorber achieves a broadband absorption from 0.85 to 1.926 THz with the absorptivity beyond 90% at normal incidence, and the bandwidth is 1.076 THz, which is 77.52% with respect to the central frequency. The broadband and the high absorption are mainly resulted from the strong electromagnetic resonance and overlapping of resonant frequencies. Moreover, the proposed absorber has a property of wide angle absorptivity for both TE and TM polarizations, and thus can play an important role in terahertz imaging, detecting, and stealthy technology.