Theoretical Investigation Of Different Electromagnetic Metamaterials Applied In Polarization Transformers And Near-field TPV Systems

Metamaterial is a manmade artificial material with unusual physical properties.It has been the hot topic in the optical area in the past decade and can exhibit some novel quantities,such as the negative refraction,the reversed Doppler effect and the reversed Cerenkov radiation.Based on these special properties,metamaterials have potential applications in many fields,including optical communication,optical military detection,optical integration systems and etc.This paper mainly focuses on the application of three classical metamaterials in polarization transformer and near-field TPV system and the summarized content is listed as follows:(1)The polarization manipulating ability of epsilon-near-zero material was studied.When a linearly polarized wave is incident on an epsilon-near-zero material,the wave reflected by the material was obtained by Maxwell’s equations and boundary condition.The results show that the epsilon-near-zero material can realize the transition from linearly polarized wave to circular polarized wave.Even for an epsilon-near-zero material with large loss,the conversion efficiency can still reach up to 74%.(2)The polarization manipulating ability of gradient index material was studied.The total reflection achieved by plane or circular gradient index material is demonstrated through underlying physical mechanism and simulation software.The linearly polarized wave could be circular polarized through the reflection of gradient index material.However,the gradient index material is unable to achieve broadband transition of polarization state,which means that the effect of this material is very limited.(3)The effect of metamaterial radiator consisted of the array of thin wires and SRRs in the performance improvement of near-field TPV system was studied.Based on the fluctuation-dissipation theorem and the effective medium theory,the theoretical model of near-field TPV system with a metamaterial radiator was constructed.The results show that through the optimized metamaterial parameters,the system output power or system conversion efficiency could be improved by surface polaritons.