Nodal Discontinuous Galerkin Method for Time-Domain Lorentz Model Equations in Meta-Materials

In this paper,Nodal discontinuous Galerkin method is presented to approxi-mate Time-domain Lorentz model equations in meta-materials.The upwind flux is cho-sen in spatial discrete scheme.Low-storage five-stage fourth-order explicit Runge-Kutta method is employed in time discrete scheme.An error estimate of accuracy O(τ^(4)+h^(n))is proved under the L^(2)-norm,specially O(τ^(4)+h^(n+1))can be obtained.Numerical exper-iments for transverse electric(TE)case and transverse magnetic(TM)case are demon-strated to verify the stability and the efficiency of the method in low and higher wave frequency.

Extending the Frequency Range of Surface Plasmon Polariton Mode with Meta-Material

The frequency range that surface plasmon polariton(SPP) mode exists is mainly limited by the metal material.With high permittivity dielectrics above metal surface, the SPP mode at high frequency has extremely large loss or can be cutoff, which limits the potential applications of SPP in the field of optical interconnection, active SPP devices and so on.To extend the frequency range of SPP mode, the surface mode guided by metal/dielectric multilayers meta-material has been studied based on the theory of electromagnetic field. It is demonstrated that surface mode not only could be supported by the meta-material but also extends the frequency to where conventional metal SPP cannot exist. Meanwhile, the characteristics of this surface mode, such as dispersion relation, frequency range, propagation loss and skin depth in metamaterial and dielectrics, are also studied. It is indicated that, by varying the structure parameters, the meta-material guided SPP mode presents its advantages and flexibility over traditional metal one.

Ceramic-based meta-material absorber with high-temperature stability

With the continuous exploration of uncharted and extreme environments,enhanced temperature robustness of passive devices has become particularly important.In this study,a ceramic-based meta-material absorber with exceptional temperature stability is developed using a fusion design approach that combines rare metal-based tungsten bronze structural ceramics and meta-materials.Specifically,the absorbance of the meta-material array based on Mie resonance exceeds 49.0%in both waveguides and free space,approaching the theoretical limit.According to impedance analysis,the absorption performance can be distinctly correlated with the dielectric loss(Q_(f)).Notably,the high-temperature robustness is verified to still be effective at 400℃.These advancements in our design allow for the use of monolithic materials in fabricating temperature-stable perfect absorbers,providing greater freedom in the dielectric performance and expanding their potential applications,including in space exploration and 5G millimeter-wave scenarios.

Material parameter equation for rotating elliptical spherical cloaks

By using the coordinate transformation method, we have deduced the material parameter equation for rotating elliptical spherical cloaks and carried out simulation as well. The results indicate that the rotating elliptical spherical cloaking shell, which is made of meta-materials whose permittivity and permeability are governed by the equation deduced in this paper, can achieve perfect invisibility by excluding electromagnetic fields from the internal region without disturbing any external field.

Observation of trapped light induced by Dwarf Dirac-cone in out-of-plane condition for photonic crystals

Existence of out-of-plane conical dispersion for a triangular photonic crystal lattice is reported. It is observed that conical dispersion is maintained for a number of out-of-plane wave vectors（k;）. We study a case where Dirac like linear dispersion exists but the photonic density of states is not vanishing, called Dwarf Dirac cone（DDC） which does not support localized modes. We demonstrate the trapping of such modes by introducing defects in the crystal. Interestingly, we find by k-point sampling as well as by tuning trapped frequency that such a conical dispersion has an inherent light confining property and it is governed by neither of the known wave confining mechanisms like total internal reflection, band gap guidance. Our study reveals that such a conical dispersion in a non-vanishing photonic density of states induces unexpected intense trapping of light compared with those at other points in the continuum. Such studies provoke fabrication of new devices with exciting properties and new functionalities.

Surface plasmon polaritons of symmetric and asymmetric metamaterial slabs

The p and s-polarized surface plasmon polaritons （SPPs） of symmetric and asymmetric slabs formed arbitrarily by four types of conventional materials： dielectrics, negative dielectric permittivity materials, negative magnetic permeability materials, and left-handed materials are comprehensively analysed. The existence regions, dispersion relations, and excitation of SPPs in different frequency regions are investigated in detail. For symmetric slabs, the numbers and the frequency positions of surface polariton branches are quite different. At the same time, the pairs of the p or s-polarized SPP branches occur in the same frequency range. For asymmetric slabs, the SPP branches in mid- and high-frequency ranges are greatly different. In addition, the slab thickness has a great effect on SPPs of asymmetric and symmetric slabs. The attenuated total reflection spectra for the cases of p and s polarizations in these slabs are also calculated.

Recent Progress in Research and Development of Reconfigurable Intelligent Surface

We aim to provide a comprehensive overview of the progress in research and development of the reconfigurable intelligent surface(RIS)over the last 2-3 years in this paper,especially when the RIS is used as relays in next-generation mobile networks.Major areas of re-search in academia are outlined,including fundamental performance,channel estimation,joint optimization with antenna precoding at base stations,propagation channel modeling and meta-material devices of RIS elements.Development in industry is surveyed from the aspects of performance potentials and issues,realistic joint optimization algorithms,control mechanisms,field trials and related activities in standardiza-tion development organizations(SDOs).Our views on how to carry out the engineering-aspect study on RIS for 6G systems are also presented,which cover the realistic performance,the comparison with other topological improvements,approaches for channel modeling,factors for de-signing control mechanisms and the timeline for RIS standardization.

Subwavelength electromagnetics

Subwavelength electromagnetics is a disci- pline that deals with light-matter interaction at subwave- length scale and innovative technologies that control electromagnetic waves with subwavelength structures. Although the history can be dated back to almost one hundred years ago, the flourish of these researching areas have been no more than 30 years. In this paper, we gave a brief review of the history, current status and future trends of subwavelength electromagnetics. In particular, the milestones related with metamaterials, plasmonics, meta- surfaces and photonic crystals are highlighted.

Acoustic Nanowave Absorption through Clustered Carbon Nanotubes Conveying Fluid

Absorption of acoustic nanowave in specific frequency region is important for the design of acoustic filter. This paper puts forward a meta material model made up of fluid-conveying carbon nanotubes （CNT）, which can absorb acoustic nanowave in a given frequency range by adjusting the lengths and fluid velocities of themselves. Absorption coefficients are calculated out through the combination of the finite element method with the theoretical model, which are 0.4-0.55 relating to different fluid velocities for the crossing-distributed model. Comparisons are made between the crossed model and the aligned one, which prove that the CNT forest with crossed distribution is more effective in acoustic wave absorption.