Metamaterial Electromagnetic Wave Research Articles

Loss Analysis of the Electromagnetic Metamaterial Applied to Antenna Size Reductions

The research of transformation electromagnetics uses spatial coordinate transformation method to transform Maxwell’s equations for the propagations of electromagnetic waves in space, thereby achieving the goal of designing the path of electromagnetic waves, which eventually leads to a more complex tensor design of its constitutive parameters of metamaterials. This demand for artificial design of material parameters has been combined with the rapid development of micro-scale, molecular-scale, and atomic-scale experimental engineering techniques in recent years, enabling metamaterials to be developed, fabricated, and applied in various frontier fields. In this paper, the metamaterial electromagnetic wave concentrator used to reduce the antenna size is mainly discussed and detailed simulations and researches on the electromagnetic lossy conditions of the metamaterial parameters are given, which can better verify the electromagnetic scattering performance under actual engineering conditions. Solutions and quantitative simulations for the attenuation characteristics are also provided, which can deepen the research on the engineering performance of the metamaterial electromagnetic transformation devices.

Propagation of Dirac waves through various temporal interfaces, slabs, and crystals

We investigate the influence of the temporal variations of various medium parameters on the propagation of Dirac-type waves in materials where the quasiparticles are described by a generalized version of the pseudospin-1/2 Dirac equation. Our considerations also include the propagation of electromagnetic waves in metamaterials with the Dirac-type dispersion. We focus on the variations of the scalar and vector potentials, mass, Fermi velocity, and tilt velocity describing the Dirac cone tilt. We derive the scattering coefficients associated with the temporal interfaces and slabs analytically and find that the temporal scattering is caused by the changes of the mass, Fermi velocity, and vector potential, but does not arise from the changes of the scalar potential and tilt velocity. We also explore the conditions under which the temporal Brewster effect and total interband transition occur and calculate the change in total wave energy. We examine bilayer Dirac temporal crystals where parameters switch between two different sets of values periodically and prove that these systems do not have momentum gaps. Finally, we assess the potential for observing these temporal scattering effects in experiments.

Metamaterial electromagnetic wave absorbers and devices: Design and 3D microarchitecture

• In this review, the design principles of the new MMAs: bionic design and new artificial design, are explored. • Bionic design mainly includes the design of imitating the microstructures of moth-eye and diatom frustum. • 3D printing technology make MMAs light and more complex. Metamaterials refer to a class of artificial composite structures with supernormal physical properties that natural materials do not have. The emergence of metamaterials has opened up new research directions for classical electromagnetic theory and made it possible to manipulate electromagnetic waves effectively. One of most important applications of metamaterials is metamaterial absorbers (MMAs). The properties of MMAs depend on the material composition, cell size and structure, which could often achieve "perfect" absorption through reasonable design. This review starts with the development of MMAs and describes the status of this absorber, then mainly focuses on bionic design and new artificial design. Specifically, it is to draw inspiration from natural plants and animals, design novel structures to get better absorbing properties. Furthermore, the artificial design can achieve the optimize absorption capacity as well as absorption bandwidth. What's more, this review summarizes the 3D printing technology to prepare MMAs that are different from traditional printed circuit board technology. The MMAs produced by 3D printing technology can prepare more complex shapes, and has light weight and better absorbing properties. This review mainly reports the design (bionic and artificial) and preparation (3D printing technology) of metamaterial absorbers (MMAs) with super-absorbent capacity. Specifically, this review is to draw inspiration from natural plants and animals, design structures with the capacity to manipulate electromagnetic waves absorption, and use artificial patterning methods to optimize absorption capacity as well as absorption bandwidth.

Localized surface plasmon resonance modulation of totally encapsulated VO2/Au/VO2 composite structure

We design and fabricate a totally encapsulated VO2/Au/VO2 composite structure which is aimed to improve the tunability of the localized surface plasmon resonance (LSPR) peak. In this work, the structure will ensure all the Au NPs’ resonant electric field area is filled with VO2. The modulation range of the totally encapsulated structure is larger than that of the semi-coated structure. To further improve the modulation range, we also explore the VO2 thickness dependence of the structure’s LSPR modulation. With the increase of the top layer VO2 thin film thickness, the modulation range becomes larger. When the thickness is about 80 nm, the absorption peak achieves a largest shift of 112 nm. FDTD solution and equivalent model of series capacitor are used to explain the phenomenon. These results will contribute to the area of metamaterial electromagnetic wave absorber and other fields.

Comment on “a compact ultra‐thin ultra‐wideband microwave metamaterial absorber”

AbstractIn the recently published article, Ramya et al. (Microw Opt Technol Lett. 2017;59:1837–1845. https://doi.org/10.1002/mop.30636) proposed asymmetrical metamaterial absorber structure for wideband applications. It was shown that, the reported structure has wideband absorptivity (above 85%) from 10.36 to 16.67 GHz. It is demonstrated in this article that, the reported unit cell is not a metamaterial electromagnetic wave absorbing structure. It is found that, peak absorptivity is 37.6%, 26.5%, and 28.6% at frequencies 10.5, 13.9, and 16.2 GHz, respectively. The strong wideband absorption caused in the original article is due to ignorance of cross‐polarized reflections in the calculation of absorbivity rather than true absorption as authors claimed.

X-band Operations Metamaterial Absorber with Extended Circular Ring Topology for Size Reduction

<p>A metamaterial electromagnetic wave absorber consisting of a big circular ring patch with four smaller suppression circular rings is presented in this report. The metamaterial electromagnetic wave absorber introduces the concept of size reduction by suppressing the resonance frequency. An FR4 substrate was used and the incidental wave angles were varied from 0<sup>0</sup> to 60<sup>0</sup>. Simulations results shows peak absorption of 100% was achieved at 10.7 GHz by the absorber for both TE and TM polarization incident waves. Minimum absorption for both TE and TM mode of 90.6% was achieved under TE mode. The metamaterial absorber was being tested with and Ultra-wide band antenna and the results were reported.</p>

A visible-near infrared wavelength-tunable metamaterial absorber based on the structure of Au triangle arrays embedded in VO2 thin film

Abstract We propose a metamaterial electromagnetic wave absorber which is aimed to achieve the wide tunability of resonance absorption peak in visible and near-infrared (NIR) regime. The metamaterial absorber consists of Au triangle nanoparticle arrays, vanadium dioxide (VO2) film dielectric layer and the gold reflective layer, and the Au triangle arrays are embedded in the VO2 film. We explore the change of resonance wavelengths affected by the thickness of the VO2 dielectric layer. When the thickness of VO2 film is 90 nm, the absorption peak achieves a large tunability of 56.2% while the VO2 undergoes a structural transition from metallic phase (m-VO2) to insulator phase (i-VO2). The large wavelength tunability can be explained by a hybrid electric resonance and magnetic resonance mode from the electromagnetic field distributions at the resonance wavelengths. The absorbers with tunable resonance wavelengths would be beneficial to the sensor and detector applications in terms of heat or light signal.

Wireless Inter/Intra-Chip Communication Using an Innovative PCB Channel Bounded by a Metamaterial Absorber

This letter demonstrates the feasibility of applying I/O pins as chip Tx/Rx antennas for implementing wireless inter/intra-chip communications (WIICs). An innovative printed circuit board (PCB) medium is presented as a signal propagation channel, which is specially bounded by a metamaterial electromagnetic wave absorber to improve electromagnetic environment pollution. Presented is a 20.4-GHz WIIC communication system, mainly including a transmitter and a receiver. The bit-error-rate (BER) performance of a coherent binary phase-shift keying interconnect system is evaluated. It is shown that the system performance degrades as the separation distance of the transceivers increases. A data rate of 1 Gb/s with a BER at the level of ${10^{ - 5}}$ on the PCB investigated is achieved for the transmitted power of 10 dBm.

On the history of backward electromagnetic waves in metamaterials

In this Letter to the Editor, I review briefly a historical background of the research on backward waves carried out in the XX century. I also provide a brief introduction to the isofrequency method of analysis for metamaterials and discuss a few unusual examples of wave phenomena at the interfaces.

Multipole approach in electrodynamics of metamaterials

Metamaterials are artificial media that allow tailoring the macroscopic properties of light propagation by a careful choice of nanoplasmonic inclusions it is made of. A simple and versatile analytical model describing propagation of electro magnetic waves in metamaterials is suggested. The model is based on the secondary averaging procedure in full analogy with the ordinary one accepted for Maxwell equations, where the nanoplasmonic inclusions (typically referred to as metaatoms or metamolecules) are considered similarly to natural atoms or molecules. The model turns out to be beneficial improvement in the theoretical description of metamaterials since it contributes to the physical understanding of optical phenomena in metamaterials and provides good quantitative correspondence with the results of rigorous numerical methods, and is able to predict new effects.

Singularities of ray and caustic structures of electromagnetic waves in metamaterials

Ray and caustic structures formed during propagation of electromagnetic waves from a point source of electromagnetic radiation in a layer of a metamaterial with a negative refractive index are studied. Propagation of waves in a homogeneous layer bounded by curvilinear surfaces with circular and parabolic shapes, i.e., in lenses of metamaterials, is analyzed. Propagation of waves in an inhomogeneous layer is considered in the cases of longitudinal and transverse variations in the refractive index. Caustic structures corresponding to wave catastrophes of caspoid and ombilic series are found. The possibility of backward waveguide propagation in a metamaterial is shown

Observation of Brewster’s effect for transverse-electric electromagnetic waves in metamaterials: Experiment and theory

We have experimentally realized Brewster's effect for transverse-electric waves with metamaterials. In dielectric media, Brewster's no-reflection effect arises only for transverse-magnetic waves. However, it has been theoretically predicted that Brewster's effect arises for TE waves under the condition that the relative permeability ${\ensuremath{\mu}}_{\mathrm{r}}$ is not equal to unity. We have designed an array of split-ring resonators as a metamaterial with ${\ensuremath{\mu}}_{\mathrm{r}}\ensuremath{\ne}1$ using a finite-difference time-domain method. The reflection measurements were carried out in a $3\text{\ensuremath{-}}\mathrm{GHz}$ region and the disappearance of reflected waves at a particular incident angle was confirmed.