Research On The Synergistic Modulation To Electromagnetic Waves By Plasma Stealth And The Subwavelength-plasma-based Intensification Effect

Plasma stealth is an active cloaking technology with great potential.Compared with shaping and material stealth techniques,plasma stealth is advantageous because it shows a high absorption rate,a wide absorption bandwidth,and plasma’s parameters are dynamically and continuously tunable.However,currently,the stability and sustainability of plasma stealth are relatively bad since plasma can also block communication signals when performing stealth function.In order to solve the communication bottleneck long existing in plasma stealth and inspired by theories in photonics and plasmonics,this article proposes the synergism between plasma stealth and the subwavelength-plasma-based intensification effect.Considering practical needs in real applications,we built and optimized a 3D simulation model where an electrically small antenna is covered by one or two plasma layers in three different cases,which denotes that the frequency of detecting waves is less than,equal to or larger than that of communication signals,respectively.Based on this model,the influence of plasma’s key parameters on the effectiveness of the synergism and the corresponding physical mechanisms were investigated.On this basis,we summarized three techniques that are able to accomplish the synergistic effect.When the frequency of detecting waves is less than that of communication signals,we revealed the matching relationship between inner and outer plasma parameters when the synergistic effect is available by scanning outer plasma parameters while fixing inner plasma parameters based on a two-layered plasma structure.Then,we found that the synergism is based on the subwavelengthplasma-based intensification effect and the scattering cancellation method or the generalized Kerker effects.On this basis,the relationship between outer plasma’s parameters and target’s spatial scattering characteristics is elucidated.What is more,results show that the hybridized plasmon theory plays an important role in promoting the effectiveness of the synergistic effect.When the frequency of detecting waves is equal to that of communication signals,the feasibility to fulfill the synergistic effect based on the scattering cancellation method or the generalized Kerker effects and the subwavelengthplasma-based intensification effect,and corresponding physical mechanisms were discussed.In terms of the synergism based on the scattering cancellation method,we discovered that one can improve its effectiveness by increasing initial radiation gain via comparing effectiveness under different inner plasma’s parameters.As for the synergism based on the generalized Kerker effects,it is shown that one plasma shell exhibits equivalent cloaking and intensification effect,which means the two-layered structure can be simplified and optimized to one plasma shell,and the corresponding mechanisms are further analyzed.When the frequency of detecting waves is larger than that of communication signals,our work can be divided into two parts.In terms of the case where the angular frequency of detecting waves is larger than the inner plasma frequency,we investigated the parameter region for effective synergism where only inner plasma coats an antenna by both theoretical analysis and simulation.As for the circumstance in which the angular frequency of detecting waves is less than the inner plasma frequency,we discussed the feasibility to accomplish the synergistic effect based on the subwavelength-plasma-based intensification effect and the scattering cancellation method or the generalized Kerker effects.In the meantime,the effectiveness of the synergistic effect is optimized by increasing initial radiation gain or the frequency of communication signals and by applying the plasma shell structure.Furthermore,we summarized three techniques that can realize the synergistic effect,and discussed the applicative frequency range for detecting and communication waves and the corresponding principles for choosing plasmas’ parameters,respectively,which provides guidance on engineering design in the next step.