Five-band Metamaterial Absorber Research Articles

Five-Band Tunable Terahertz Metamaterial Absorber Using Two Sets of Different-Sized Graphene-Based Copper-Coin-like Resonators

In this paper, a five-band metamaterial absorber with a tunable function in a terahertz band is proposed, which consists of a gold grounding layer, a polyimide dielectric layer, and a periodic patterned graphene layer. The patterned graphene layer is constructed from two sets of copper-coin-shaped structures of different sizes. The designed absorber achieves absorptions of 96.4%, 99.4%, 99.8%, 98.4%, and 99.9% at 4.62 THz, 7.29 THz, 7.70 THz, 8.19 THz, and 8.93 THz, respectively, with an average absorption intensity of 98.78%. The physical mechanism of this five-band absorber was explained by the impedance matching principle and electric field distribution. The absorption performance of the five-band absorber can be effectively tuned by changing the geometry of the patterned graphene array and the thickness of the dielectric layer. Given that the resonant frequency of the absorber varies in proportion to the Fermi level, by varying the Fermi level of the graphene hypersurface, we can achieve the continuous tuning of the absorption performance over a wide frequency range. The five-band absorber has a stable absorption performance over a wide incidence angle of 0–65°, and by combining the merits of high absorption, dynamic adjustability, and a large number of absorption peaks, the given absorber could have great potential for applications in nondestructive testing, imaging, communication, sensing, and detectors.

Design, fabrication and characterization of terahertz five-band metamaterial absorber

Design, fabrication and characterization of terahertz five-band metamaterial absorber

Design and analysis of a five-band metamaterial absorber

In the microwave band, we designed a new multi-band metamaterial absorber (MMA) consisting of a Buddhist logo metal resonator enclosed by a non-closed rectangular frame and a metal soleplate, separated by a dielectric layer. Through calculation, five near-perfect absorption peaks were obtained at 5.24, 8.84, 14.28, 15.96 and 18.6 GHz, with absorption rates of 96.39%, 98.13%, 98.26%, 98.07% and 99.75%, respectively. By analyzing the distribution of electromagnetic field and surface current, the absorption mechanism is further explored. Experimental results are consistent with the calculated results. Furthermore, how design parameters affect absorb property has been studied. The MMA has the characteristics of flexible structure and relatively higher absorption rates, which makes it have good potential in stealth materials, radar detection, electromagnetic sensing and other fields.

Design and Analysis of a Five-Band Polarization-Insensitive Metamaterial Absorber

A five-band metamaterial absorber (MMA) is presented. The proposed absorber consists of a three-layer structure of the top metal resonator, intermediate dielectric layer, and bottom metal plane. The top structure takes the centroid as the center and spreads out in a three-pronged shape with an average of 360°, and the ends bifurcate again. The calculation was carried out by the professional software to iteratively optimize the absorption effect of MMA in the microwave range. The results show that the MA has five peaks at resonant frequencies of 5.984 GHz, 12.232 GHz, 18.128 GHz, 18.414 GHz, and 20.592 GHz, with peaks of 0.9925, 0.9968, 0.9783, 0.9754, and 0.9975. By analyzing the electromagnetic field and surface current distribution of the absorber, the absorption mechanism is further verified, and the corresponding influence on the absorption spectrum is studied according to different polarization angles and incident angles. The effects of different resonator structure size and dielectric layer thickness on absorption rate were also discussed, and the distribution of electromagnetic fields is analyzed to reveal the existence of electric dipole resonance and magnetic resonance. Through comparing experiments and simulations, it is found that the peaks of the 1st, 2nd, and 5th have smaller absorption errors and frequency deviation, while the peaks of the 3rd and 4th have large ones. The five-band absorber has potential application in multiband electromagnetic stealth, bionic sensor, thermal radiation measuring instrument, and so on.

A polarization insensitive compact ultrathin wide-angle penta-band metamaterial absorber

In this paper, the design, fabrication, and measurements of a compact ultrathin five-band metamaterial absorber with wide-angle stability have been presented. The unit cell of the absorber consists of five concentric metallic circular rings printed as the top layer of a grounded dielectric substrate of thickness 1 mm. The radii and the intermediate gap between the rings are optimized such that the proposed absorber exhibits five distinct absorption peaks at frequencies of 5.28, 7.36, 9.52, 12.64, and 16.32 GHz with absorptivities of 92.03, 90.46, 95.10, 91.65, and 91.10%, respectively. The proposed absorber is polarization insensitive for both TE and TM incident wave and results high absorption for wide incidence angle up to 60°. The proposed structure is compact with its unit cell size of 0.54 λ0 and ultrathin with thickness of ~λ0/19 corresponding to the highest frequency of absorption. Surface current and field distributions are studied to understand the absorption mechanism. A prototype of the proposed absorber is fabricated and experimentally tested for different polarization and incident angles. The measured results are observed to be in agreement with the simulated ones. The proposed absorber is suitable for potential applications due to its multi-band absorption.

Quad-Band Terahertz Absorber Based on a Simple Design of Metamaterial Resonator

A new design approach for achieving quadband terahertz metamaterial absorber, formed by an asymmetric resonator and a metallic board separated by a certain thickness dielectric layer, is numerically studied and demonstrated. Results show that the absorber has four high absorption (greater than 98%) resonance bands (or peaks). The physical origin of the absorber is attributed to four different resonance modes of the single-patterned resonator. The proposed device resolves large unit size, complex resonance structure, and time-consuming and costly fabrication steps, which previously reported absorbers frequently encountered. Moreover, the five-band metamaterial absorber can be obtained by further optimizing the parameters of resonator. The proposed absorber has application prospects in many areas such as materials detection, thermal imaging, and biological sensing.

Two compact SRR resonators enabling five-band perfect absorption

A simple and compact five-band metamaterial absorber, consisted of two split-rings and a metallic board spaced by a certain thickness dielectric layer, is numerically investigated and studied. The designed absorber provides five obvious bands, and each resonance peak has the absorption coefficient great than 98.7% on average. The operating mechanism of five-band near-unity absorption is due to the combined effect of the LC, dipole and surface resonance of structure. Moreover, the effects of the parameters are investigated to verify the origin of the five-band absorption. The proposed device can be potentially used in biological sensing, material detection, and thermal imaging.

Multi-band polarization insensitive metamaterial absorber with dual cross-wires structure

A five-band metamaterial absorber (MMA) based on a simple planar structure is proposed. It utilizes different areas of a single unit cell to match impedance, and produces different absorptive frequencies. Numerical calculation shows that the MMA has five different absorption peaks at 3.78 GHz, 7.66 GHz, 10.9 GHz, 14.5 GHz and 16.7 GHz, and their absorption rates reach 95.5%, 98.6%, 95.7%, 96.6% and 99.8%, respectively. The proposed structure is polarization insensitive for transverse electric (TE) and transverse magnetic (TM) incident waves. Also, the absorptive characteristics over large incident angles are examined. In addition, we analyze the absorption mechanism by the surface current density and power flow density distributions. This simple structure provides a way to design multi-band MMA, and also saves the cost of fabrication.

Design of a Four-Band and Polarization-Insensitive Terahertz Metamaterial Absorber

We present a four-band and polarization-insensitive terahertz metamaterial absorber formed by four square metallic rings and a metallic ground plane separated by a dielectric layer. It is found that the structure has four distinctive absorption bands whose peaks are over 97% on average. The mechanism of the four-band absorber is attributed to the overlapping of four resonance frequencies, and the mechanism of the absorption is investigated by the distributions of the electric field. In particular, the frequency of each absorption peak can be flexibly controlled by varying the size of the corresponding metallic ring. The proposed concept is applicable to other types of absorber structures and can be readily scaled up to the structures that are working in the microwave frequency range. Moreover, the characteristic of the design can be used to design a five-band metamaterial absorber by adding one more metallic ring. The proposed absorber has potential applications in detection, imaging, and stealth technology.

Multi-band polarization-insensitive metamaterial absorber based on Chinese ancient coin-shaped structures

In this paper, the design, simulation, fabrication, and measurement of the five-band metamaterial absorber (MMA) based on Chinese ancient coin-shaped structure are proposed. Simulation results show that the proposed absorber has five distinctive absorption peaks at frequencies of 2.538 GHz, 7.092 GHz, 9.702 GHz, 13.302 GHz, and 15.588 GHz with the absorptivity of 0.99, 0.99, 0.99, 0.98, and 0.99, respectively. Experiment results matches well with the simulation. Both simulation and experiment results exhibit that the MMA sample is polarization insensitive for transverse electric and transverse magnetic incident wave. It also shows that high absorption for wide angle of incidence is up to 60°. Finally, the current distribution for the MMA is presented to gain an insight into the physics behind the multiple absorption mechanism. The five-band absorber is promising candidates as absorbing elements in scientific and technical applications because of its multiband absorption, polarization insensitive, and wide angle incidence.