Study On The Electromagnetic Absorption Based On Graphene Sub-Wavelength Material

As a new kind of electromagnetic material, sub-wavelength materials(SWM) have been researched widely in recent years. The electromagnetic properties of SWM are strongly dependent on the structure, proportion, and arrangement of the unit. So SWM provides great flexibilities in the modulation of electromagnetic wave and has many potential applications in electromagnetic stealth, antenna, and super-resolution imaging.However, traditional SWM can’t fulfill the requirement of the flexibilities in many applications due to the revolution of the technology. Many researchers have focused on how to realize dynamical modulation on the electromagnetic wave. Lots of technologies and materials like micro-electro-mechanical-system(MEMS), semiconductor, and liquid crystal have been employed to modulate the electromagnetic wave dynamically. However, there are still many limits such as the complex structure and the flat form.Recently, graphene has attracted a lot of attention due to its unique electromagnetic properties. One of the most fantastic properties of graphene is that its conductivity can be changed by the chemical potential. This can be used to realize dynamical modulation on the electromagnetic wave with more simplex structure.In this paper, we study the absorption properties of SWM based on the graphene and mainly focus on the realization of dynamically tunable absorption and the broadening of the bandwidth. The main work and conclusion are listed as following:1. We studied the absorption properties of the absorber based on single layer of graphene sub-wavelength structure employing the computing simulation and the theory of the effective medium and realized a dynamically tunable narrowband absorption;2. Based on the study of the absorption properties of the absorber based on single layer of graphene sub-wavelength structure, we broadened the absorption bandwidth with stacked graphene sub-wavelength structure. And we have analyzed the hybrid resonant mode in the stacked structure;3. Combining graphene with metallic sub-wavelength structure, we realized a dynamically tunable broadband absorption. We analyzed the physics origin with the theory of the effective medium.