We report the design of a wide-band and quasi-omnidirectional tabulate metamaterial absorber in the terahertz regime. Simulated results indicate that the absorber has a wide-band strong absorption between 4.36 and 4.91 THz, which is polarization insensitive and wide incident angle. Retrieved real parts of the impedance show that by adjusting the electromagnetic response of the metamaterial, the impedance of the absorber could be tuned to match approximatively the impedance of the free space on one side and do not match to the impedance of the free space on the other side, resulting in the minimal reflectance, the minimal transmission and the highest absorbance in the absorption band. Simulated absorbance values under three different loss conditions suggest that high absorbance is mainly due to metallic absorption and dielectric loss can be used to absorb partial energy if there is no metallic absorption. Simulated absorbance values under different electric conductivity values and copper thicknesses suggest that the intensity of metallic absorption can be boosted up by adopting metal of high conductivity or reducing the thickness of metal properly. This absorber may have broad applications in many scientific and technological fields.%在太赫兹波段设计了一种宽频带准全向的平板超材料吸波体.仿真结果表明,该吸波体在4.36～4.91THz之间具有极化不敏感和宽入射角的强吸收.提取的等效阻抗实部表明,可以通过调节超材料的电磁响应造成吸波体一侧与自由空间近似阻抗匹配、另一侧与自由空间阻抗不匹配,从而在吸收频带内同时实现反射率和传输率最小、吸收率最大.仿真的三种不同损耗情况下吸波体的吸收率表明,吸波体的强吸波特性主要源于金属损耗；金属无耗时,基板的介质损耗只能吸收部分能量.仿真的金属覆层在不同电导率和不同厚度情况下吸波体的吸收率表明,可以通过选用合适高电导率的金属以及适当减小金属覆层的厚度来加强金属损耗的强度.该吸波体可能在许多领域具有广泛的应用.
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