小型化超材料吸波体设计与电磁吸收分析

Design of miniaturized metamaterial absorber and analysis of electromagnetic absorption mechanism

为解决高频率、高集成度电子设备的电磁辐射问题,提出了一种类似“三明治”的超材料吸波体结构.该结构的金属层印刷在FR4基板两侧,利用顶层两组金属条增加谐振点,实现带宽拓展.采用S参数反演得到本构参数,同时通过等效电路模型和表面电流分布验证该结构的吸波机理,并进行了实物的加工和测量.整个吸波体的单元尺寸为0.1_λ(L)×0.1_λ(L)(_λ(L)为最低截止频率对应的波长),厚度仅为0.062_λ(L),实测结果表明,在不同极化方式下10~18 GHz的吸收率均高于90%,仿真与实测结果具有较好的一致性.该结构具有小型化、超宽带、高吸收率、极化不敏感等特点,为小型电子设备的辐射问题提供了一种新型电磁辐射抑制设计方法.

A type of"sandwich"metamaterial absorber is developed,fabricated and experimentally demonstrated to solve the electromagnetic radiation problem of high frequency and high integration electronic equipment.The metal layer of this structure is printed on both sides of the FR4 substrate,and the two sets of metal strips on the top layer are used to increase the resonance point and realize the expansion of the bandwidth.To understand the electromagnetic wave absorption mechanism,an equivalent circuit model of the metamaterial absorber unit cell is constructed to investigate the absorbing characteristics,and surface current distributions are analyzed at absorption peaks.The size of the unit is only about 0.1_λ(L)×0.1_λ(L) where _λ(L) is the wavelength of the lowest frequency,and the total thickness of the absorber is only 0.062_λ(L).Simulated and experimental results show that the absorber exhibits absorptivity above 90%from 10 GHz to 18 GHz under different polarization.Measurement results show good agreement with the numerically simulated results.The structure is characterized by miniaturization,ultra-wideband,high absorptivity and polarization-insensitive,which provides a new type of suppression structure for radiation problems of small electronic equipment.