A Six-Band Terahertz Absorber Based on Symmetrical Split Rings

A six-band terahertz absorber composed of four split rings on a ground layer separated by a substrate is proposed. It is clearly observed that the pattern has six absorption peaks in which the peaks are all close to 99%. The near unity absorption of six band absorber can be interpreted through the overlapping of the fundamental resonances and the hybrid resonance frequencies of the pattern. Moreover, the variation of the incident angle could be used to tune the resonance frequencies of the absorption bandwidth. In addition, variations of geometrical parameters provide considerable freedom to make remarkable changes at the resonance frequencies of the absorber. The proposed absorber platform appears to be particularly suitable for sensing, detection, and imaging applications.