The equivalent medium theory of metamaterials provides a way to obtain their effective constitutive parameters.However,because of its non-reciprocity,the complexity of the electromagnetic coupling,and a metallic botto...The equivalent medium theory of metamaterials provides a way to obtain their effective constitutive parameters.However,because of its non-reciprocity,the complexity of the electromagnetic coupling,and a metallic bottom layer,it has been challenging to retrieve them from a metamaterial absorber.In this paper,we propose a method without any approximation to obtain them,in which the non-reciprocity and the strong electromagnetic coupling are included.Compared with the three methods such as symmetric metamaterial method,asymmetric metamaterial method and metasurface method,our method can reveal the metamaterial absorber’s electrical and magnetic resonance and show its electromagnetic coupling coefficients.To deal with a metamaterial absorber with a metallic bottom layer,four corners of the metallic bottom layer in the unit cell are removed,making it possible to retrieve the electromagnetic parameters.Surprisingly,these results show that the metamaterial absorber with a metallic bottom layer in our example operates in a negative refraction state at the half absorption frequencies,which helps further understand the absorbing mechanism of these metamaterial absorbers.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11872013).
文摘The equivalent medium theory of metamaterials provides a way to obtain their effective constitutive parameters.However,because of its non-reciprocity,the complexity of the electromagnetic coupling,and a metallic bottom layer,it has been challenging to retrieve them from a metamaterial absorber.In this paper,we propose a method without any approximation to obtain them,in which the non-reciprocity and the strong electromagnetic coupling are included.Compared with the three methods such as symmetric metamaterial method,asymmetric metamaterial method and metasurface method,our method can reveal the metamaterial absorber’s electrical and magnetic resonance and show its electromagnetic coupling coefficients.To deal with a metamaterial absorber with a metallic bottom layer,four corners of the metallic bottom layer in the unit cell are removed,making it possible to retrieve the electromagnetic parameters.Surprisingly,these results show that the metamaterial absorber with a metallic bottom layer in our example operates in a negative refraction state at the half absorption frequencies,which helps further understand the absorbing mechanism of these metamaterial absorbers.
