Design of a Five-Band Terahertz Absorber Based on Three Nested Split-Ring Resonators

A novel five-band terahertz metamaterial absorber based on three nested split-ring resonators is proposed. It is found that the structure has five distinctive absorption bands whose peaks are average over 99%. Different from previous reports by combing the resonances of the complex structure to obtain the multi-band responses, the proposed five-band absorber uses the hybrid of the LC resonance and dipolar response of the patterned structure, thus making the proposed structure quite easy to be fabricated. Furthermore, the sensing performance of the absorber is analyzed in terms of the over layer and the surrounding index.