基于超材料与电阻型频率选择表面的薄型宽频带吸波体的设计

摘要

Three kinds of absorbers, based on square metal patch structure（SMP） metamaterials, resistance frequency selective surface （RFSS）, and the combined SMP with RFSS structures, are designed, respectively. The absorptivities of these absorbers are simulated and analyzed by FDTD method. The simulation results indicate that in a frequency range of 2-30 GHz, SMP absorber can achieve stronger multi-bands absorption by the proper design of geometrical parameters of unit cell; RFSS absorber can achieve stronger high-frequency broadband absorption by the proper design of the square resistance of unit cell. However, the bandwidth of stronger absorption is limited; the absorption of the composite absorber combined with SMP and RFSS structure is greater than 90% in a frequency range of 3--25 GHz, which has a characteristic of better impedance matching to the free space in a wide frequency range.%设计了三种类型吸波体,分别为基于正方形金属贴片（square metal patch,SMP）结构超材料吸波体、电阻型频率选择表面（Resistance Frequency Selective Surface,RFSS）吸波体和SMP与RFSS的复合结构吸波体.采用FDTD算法分别对这三种类型吸波体的电磁波吸收特性进行数值模拟分析.模拟得到的结果表明：在整个2—30 GHz频率范围内,SMP吸波体,通过几何参数的设计可以实现多频窄带强吸收;RFSS吸波体,通过方块电阻的设计可以实现高频宽带强吸收,但强吸收的带宽有限;SMP与RFSS的复合结构吸波体,在3—25GHz之间吸收率大于90%以上,且宽频范围内与自由空间具有较好的阻抗匹配特性.