A broadband absorber with multiple coupled diagonally sliced square rings at terahertz frequency using vanadium dioxide is proposed. The proposed structure exhibits more than 90 % absorption in the frequency range of 2.85–7.51 THz, with a relative bandwidth of 89.96 % and an absorption bandwidth of 4.66 THz. The absorptivity curve increases as vanadium dioxide conductivity rises from 200 S/m to 200,000 S/m, giving a wide range of tunability from 1.62 % to 100 % at 3.4 THz. Due to its geometrical symmetry, the proposed structure is independent of the polarization angle under normal incident plane waves. The proposed structure works for different incident angles for transverse electric (TE) mode and transverse magnetic (TM) mode with oblique incidence plane waves. The results demonstrate the broad bandwidth compared to the state-of-the-art designs within the same frequency band with potential applications in sensors, switches, tuning, and modulation in the terahertz range.

中文翻译：

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基于二氧化钒多重耦合对角切片方环形结构的太赫兹频率可调宽带吸收体

提出了一种使用二氧化钒的太赫兹频率下具有多个对角切片方形环的宽带吸收器。所提出的结构在2.85-7.51 THz的频率范围内表现出超过90%的吸收，相对带宽为89.96%，吸收带宽为4.66 THz。随着二氧化钒电导率从 200 S/m 上升到 200,000 S/m，吸收率曲线也随之增加，从而在 3.4 THz 下提供从 1.62 % 到 100 % 的广泛可调范围。由于其几何对称性，所提出的结构与法线入射平面波下的偏振角无关。所提出的结构适用于具有斜入射平面波的横电（TE）模式和横磁（TM）模式的不同入射角。结果表明，与相同频段内最先进的设计相比，其带宽更宽，在太赫兹范围内的传感器、开关、调谐和调制方面具有潜在应用。