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提出了一种基于集总电阻的S波段小型化超材料吸波器(Metamaterial Absorber,简称MMA)结构,并进行了理论分析和仿真验证。设计的MMA基本单元结构由加载了集总元件的电谐振器、中间隔离层和金属背板组成。利用S参数反演算法求出等效阻抗,结果表明集总电阻的加入使该MMA在较宽频带范围内有较好的阻抗匹配特性。根据等效电路理论,分析了MMA谐振吸收频率与其单元结构几何参数之间的关系。通过MMA单元结构表面电流和能流分布分析了其吸波机制。不同模式下的极化角和斜入射角吸收率表明:该MMA具有极化不敏感和宽入射角特性。进一步研究MMA结构一参数对其吸波性能的影响,通过单元结构几何参数和集总参数的调节获得最优的MMA模型。最终,通过MMA基本单元结构的进一步优化设计,使其在1.9～6.0GHz范围内吸收率达到90%以上,对应的相对带宽达到101.9%。该设计有望在电磁能量捕获及隐身领域拥有潜在应用价值。
A shunt-based S-band miniaturized Metamaterial Absorber (MMA) was proposed and its theoretical analysis and simulation were carried out. The designed MMA basic cell structure consists of an electrical resonator loaded with lumped elements, a middle spacer and a metal backplane. Equivalent impedance was obtained by S-parameter inversion algorithm. The results show that the addition of lumped resistance makes the MMA have good impedance matching characteristics over a wide frequency band. According to the equivalent circuit theory, the relationship between the resonant frequency of MMA and the geometrical parameters of its cell structure is analyzed. The mechanism of absorbing wave was analyzed by the surface current and energy flow distribution of MMA unit. Polarization angle and incidence of oblique incidence in different modes show that the MMA has polarization insensitivity and wide incidence angle characteristics. The influence of a parameter of MMA structure on the microwave absorption performance is further studied. The optimal MMA model is obtained through the adjustment of geometric parameters and lumped parameters of the unit structure. Finally, through the further optimization design of the basic unit structure of MMA, the absorption rate in the range of 1.9-6.0GHz is more than 90%, and the corresponding relative bandwidth is 101.9%. The design is expected to have potential applications in the field of electromagnetic energy capture and stealth.