Metamaterial Structure Research Articles

Design of wide bandwidth metamaterial for biosensor and wireless application

Abstract We present a new design and study of metamaterial (MTM) structure for wide bandwidth for biosensor and wireless applications. The geometrical parameters were analyzed and optimized for a triple-band operation in the frequency range of 0.1–16 GHz. The propagation characteristics were obtained using Finite element method. The proposed MTM provides negative permittivity at 1.4 GHz and negative permeability in the 9–16 GHz region. The proposed design exhibits left-handed characteristics in L, C, and Ku microwave region’s frequency band. The electric field (E), magnetic field (H), and surface current distribution of the proposed MTM unit cell have been studied at three different resonance frequencies. The proposed MTM design has a wide bandwidth of 2.2 GHz in C-band and a high effective medium ratio (EMR) of 13.37. The performance of the sensor is evaluated for different biomedical samples in the refractive index range of 1.00 to 1.39. The results indicate that the proposed biosensor has a high sensitivity in triple band of microwave region. The present research work can be highly suitable for Wi-Fi and satellite applications due to its overall performance, including wide bandwidth in the C-band, high EMR, and triple band operation.

Design and fabrication of a programmable wide-angle non-polarized terahertz receiving sensor utilizing 4F rotating structure metamaterials

Design and fabrication of a programmable wide-angle non-polarized terahertz receiving sensor utilizing 4F rotating structure metamaterials

Displacement and Force Transmissibility of a Quasi-Zero-Stiffness-Based Compliant Metamaterial Structure

Displacement and Force Transmissibility of a Quasi-Zero-Stiffness-Based Compliant Metamaterial Structure

Shielding effectiveness of high-polymer short-staple-based fabric implanted with the metamaterial structure of “split ring resonator”

PurposeElectromagnetic shielding (EMS) fabrics composed of cotton, polyester and other high-polymer short-staple fibers are widely utilized in various fields. However, the inevitable pores in these fabrics lead to the leakage of electromagnetic waves, which severely diminishes the fabric’s shielding effectiveness (SE). To address this issue, this paper proposes the implantation of a metamaterial structure known as the “split ring resonator (SRR)” into the fabric.Design/methodology/approachFirstly, the types and principles of SRRs are analyzed. Through electromagnetic simulation and emulation, the effectiveness of SRRs in dissipating electromagnetic waves is confirmed. By selecting different embroidery methods, various shapes of SRRs are implanted into the fabric. Subsequently, through testing and analysis of sample fabrics embroidered with SRRs, it is concluded that implanting appropriate SRRs into pure cotton fabrics and cotton/polyester/stainless steel-blended EMS fabrics can effectively impart or enhance the SE of these fabrics.FindingsFor pure cotton fabric without inherent SE, the peak SE value can reach over 30 dB within the 6.57 GHz–7 GHz frequency band, and the minimum SE is greater than 10 dB in the 7 GHz–9.99 GHz frequency band. For the cotton/polyester/stainless steel-blended EMS fabric, the improvement in SE across all frequency bands exceeds 10 dB, averaging around 15.6 dB. The circular type SRR demonstrates the most significant improvement in fabric SE. When the substrate is composed of pure cotton or a cotton/polyester/stainless steel blend, the circular SRRs provide an average enhancement of more than 4 dB and 6 dB, respectively, than other shapes. The fewer the holes created by the implantation method, the higher the SE of the fabric after SRR implantation, with the invisible embroidery technique being the most effective. It improves the fabric’s SE by an average of about 2 dB more than flat embroidery and can be up to an average of around 6 dB higher than the backstitch embroidery technique. For every 0.2 cm increase in the size of the SRRs, the average SE increases by about 4 dB, and for every 0.5 cm increase in the spacing between them, the fabric’s SE decreases by an average of more than 2.7 dB.Originality/valueThis paper offers a novel approach to counteract the issue of pores reducing the SE of EMS fabrics and provides a new method for developing lightweight, thin, low-cost and high-performance EMS fabric composite materials.

3D Printed Metamaterial Absorber Based on Vanadium Dioxide Phase Transition Control Prepared at Room Temperature

AbstractThe thermal phase transition characteristics of vanadium dioxide can effectively regulate the absorption performance of metamaterial absorbers. A petal‐shaped metamaterial absorber is designed based on vanadium dioxide phase transition control and prepared metamaterial samples using surface projection micro stereolithography (PµSL) 3D printing technology. Then, vanadium dioxide thin films are coated on the surface of the metamaterial using the ultrasonic spraying method. The PµSL 3D printing technology makes it possible to prepare high‐precision complex samples, and the ultrasonic spraying method enables the coating of vanadium dioxide thin films at room temperature. To demonstrate the stability of this method, two different metamaterial structures are prepared: planar structure and hemispherical structure. In the experiment, a non‐contact heating method is used to regulate the temperature of the vanadium dioxide thin film, which made the temperature of the metamaterial sample controllable, stable, and uniformly heated. The experimental results show that the designed metamaterial absorber has excellent modulation performance and excellent switching characteristics, which proves the reliability of the method.

Adapting Metamaterial Structures for a New Generation of Bone Substitute Scaffolds with the Desired Stiffness and Permeability: A Finite Element Analysis

Adapting Metamaterial Structures for a New Generation of Bone Substitute Scaffolds with the Desired Stiffness and Permeability: A Finite Element Analysis

Giant Vortex Dichroism in Simplified-Chiral-Double-Elliptical Metamaterials

Vortex dichroism in chiral metamaterials is of great significance to the study of photoelectric detection, optical communication, and the interaction between light and matter. Here we propose a compact chiral metamaterials structure composed of two elliptical SiO2 rods covered with a Au film on a substrate to achieve a significant vortex-dichroism effect. Such a structure has different responses to a Laguerre-Gaussian beam carrying opposite-orbital angular momentum, resulting in giant vortex dichroism. The influences of various structural parameters are analyzed, and the optimal parameters are obtained to realize a remarkable vortex dichroism of about 58.5%. The simplicity and giant VD effect of the proposed metamaterials make it a promising candidate for advancing chiral optical applications such as optical communication and sensing.

Using light to image millimeter wave based on stacked meta-MEMS chip

A stacked metamaterial MEMS (meta-MEMS) chip is proposed, which can perfectly absorb electromagnetic waves, convert them into mechanical energy, drive movement of the optical micro-reflectors array, and detect millimeter waves. It is equivalent to using visible light to image a millimeter wave. The meta-MEMS adopts the design of upper and lower chip separation and then stacking to achieve the “dielectric-resonant-air-ground” structure, reduce the thickness of the metamaterial and MEMS structures, and improve the performance of millimeter wave imaging. For verification, we designed and prepared a 94 GHz meta-MEMS focal plane array chip, in which the sum of the thickness of the metamaterial and MEMS structures is only 1/2500 wavelength, the pixel size is less than 1/3 wavelength, but the absorption rate is as high as 99.8%. Moreover, a light readout module was constructed to test the millimeter wave imaging performance. The results show that the response speed can reach 144 Hz and the lens-less imaging resolution is 1.5 mm.

Study of energy absorption and recovery characteristics of shape memory material zero Poisson’s ratio gradient structures

The integration of smart materials with metamaterials offers significant research value in additive manufacturing. This paper proposes a novel approach combining shape memory polymers (SMP) with zero Poisson’s ratio (ZPR) metamaterials to create better space-filling, lightweight, and high-energy absorbing materials. A cellular structure with three deformation processes was designed by adjusting the rib arm lengths of the ZPR lattice AuxHex, forming a 3D gradient structure. The cellular units were also prepared using the dual-nozzle fusion filament printing technique, and the energy absorption and shape recovery properties of various hierarchical gradient structures, compared to the uniform structure, were simulated and analyzed using the viscoelastic intrinsic model. The results indicate that all gradient structures exhibit superior energy absorption capabilities compared to uniform materials, with the energy absorption performance of the optimal gradient material being 44.32% higher than that of the nongradient material, and they also enhance the shape recovery performance to some extent. Furthermore, it was observed that when a lattice layer, which avoids internal rib contact throughout the compression process, is positioned in the middle layer, it harmonizes the deformation of the upper and lower layers, thereby improving overall stability. This configuration enhances both energy absorption and partial shape recovery performance, offering a novel approach for the design of smart material assemblies with graded metamaterial structures. This study provides a new perspective and methodology for the future design of supergradient smart material collections.

Free vibration and nonlinear transient analysis of functionally graded graphene origami-enabled auxetic metamaterial cylindrical shells: Analytical and artificial neural network approaches

This study examines the free vibration and nonlinear transient response of functionally graded graphene origami-enabled auxetic metamaterial (GOEAM) cylindrical shells under thermal conditions. The multilayered shells feature GOri distributions across their thickness, introducing distinct auxetic and thermal properties. Material properties are modeled using micromechanical models optimized via genetic programming. Employing Reddy’s third-order shear deformation theory and von Kármán’s nonlinear geometric assumptions, nonlinear kinematic relationships are formulated and solved using Galerkin method. A novel contribution is the analysis of Winkler-Pasternak elastic foundations in two configurations: centrally distributed along the shell length and concentrated at both ends. Foundation effects are quantified by integrating stiffness coefficients across contact areas, offering insights into foundation-shell interactions. Artificial Neural Networks (ANNs) are developed to predict natural frequencies with high accuracy. Trained using the Levenberg-Marquardt algorithm and tan-sigmoid transfer function, these models demonstrate robust performance through metrics like validation performance plots, regression analysis, and error histograms. Validation against literature confirms the reliability of both ANN and analytical approaches. Key findings reveal that increased GOri folding enhances the negative Poisson’s ratio but reduces Young’s modulus, decreasing shell stiffness, natural frequencies, and increasing vibration amplitudes. Additionally, centrally concentrated elastic foundations yield higher natural frequencies and smaller vibration amplitudes compared to foundations distributed at the shell ends. By integrating advanced analytical techniques with state-of-the-art ANN modeling, this study not only provides a comprehensive understanding of the dynamic behavior of FG-GOEAM cylindrical shells but also offers valuable insights for the design, optimization, and application of auxetic metamaterial structures in thermal environments.

Impactor shape effect on the shock mitigation behavior of metamaterial structures

Auxetic metamaterial structures, characterized by their negative Poisson’s ratio, have shown promising mechanical performance, particularly in shock impact scenarios. However, the complex and scenario-dependent behavior of these structures necessitates comprehensive and appropriate evaluation and verification. In this study, the shock mitigation property of an auxetic planar design in relation to the shape of the impactor surface was discussed using numerical simulation results, validated using drop testing shock experiments. Results revealed that both metamaterial shape and impactor geometry significantly influenced behavior of metamaterial response. For the plate impactor, minimal deformation at lower velocities resulted in higher peak accelerations for metamaterial configurations. Conversely for the cylindrical impactor, metamaterial structures consistently enhanced shock mitigation across all impact velocities. An Artificial Neural Network (ANN) model was developed to predict the vertical direction acceleration of the impactor by also incorporating the shape of the impactor as an evaluation parameter, in addition to the metamaterial dimensions and impact velocity. Validation with impact scenarios outside the subset of the training dataset confirmed the ANN model’s accuracy, achieving at least 94% accuracy for both impactor cases, thereby offering an efficient alternative to traditional experimental and numerical simulations for studying metamaterial shock mitigation behavior.

A novel active switchable multi-channel waveguide based on the Bragg scattering mechanism and the force-magnetic coupling effect

PurposeThis study aims to propose a novel acoustic metamaterial waveguide with active switchable channels by changing the magnetic field strength.Design/methodology/approachBased on the Bragg scattering mechanism and the force-magnetic coupling effect of magnetorheological elastomer (MRE), an acoustic metamaterial waveguide structure containing lead scatterers and an MRE/rubber matrix is constructed. By changing the external magnetic field strength, the bandgap of the acoustic metamaterial can be adjusted, and then the channels of the proposed acoustic metamaterial waveguide can be actively switched. The bandgap ranges of acoustic metamaterials containing scatterers with different sizes are different and by designing the size of the scatterers, an acoustic metamaterial waveguide can be formed. The design and control method of this study will be useful for the design of waveguides and active control of bandgaps.FindingsThe proposed switchable multi-channel waveguide and active control method can effectively control the elastic wave propagation, and the opening and closing of the channel are achieved.Practical implicationsThis study provides a new control method for waveguides and expands the application range of MRE. The proposed design concept of adjustable waveguides can be extended for the design of waveguides, metamaterials and vibration reduction structures.Originality/valueThis article proposes a waveguide structure controlled by an external magnetic field in a non-contact manner based on the principle of Bragg scattering and the force-magnetic coupling effect. The model is established, and its feasibility is demonstrated through numerical simulations.

Scalable and flexible radiative cooling composite metamaterial structure with thermally responsive emissivity tunability

Scalable and flexible radiative cooling composite metamaterial structure with thermally responsive emissivity tunability

Optimization design of multi-scale TPMS lattices based on geometric continuity fusion and strain energy driven

3D lattice structure is a kind of advanced metamaterial structure with excellent performance, such as lightweight, high specific strength and stiffness, shock damping, heat dissipation, and electromagnetic shielding capabilities. With the development of additive manufacturing technology, it has been widely concerned and developed rapidly in recent years. In order to further integrate the performance of lattice structures with mesoscale units into multi-scale optimization, this paper proposes an optimization design method for the multi-scale TPMS (Triply Periodic Minimal Surfaces) lattices based on geometric continuity fusion and strain energy driven. Regarding the challenge of geometric continuity problem of complex transition boundaries in multi-TPMS lattices, interface interpolation and density factor optimization methodologies are studied. At the same time, the mapping mechanism between lattice configuration and mechanical properties of multi-TPMS lattices is discussed in view of the requirements of multi-scale design from macro to micro configurations. Then, the multi-TPMS lattice density and configuration fields in the design domain are co-designed with the strain energy driven. Simulation and experimental results show that the mechanical properties of the multi-scale TPMS lattice designed by the proposed method are significantly improved compared with the traditional single-configuration gradient lattice, including the stiffness of the cantilever beam optimized structure is improved by 20.5% and the flexural stiffness of the three-point flexural beam optimized structure is improved by 51.3%.

Computational and experimental investigation of thermally auxetic multi-metal lattice structures produced by laser powder bed fusion

ABSTRACT Communication antennas and optical systems of space-borne satellites require highly accurate relative positioning of components despite large variations in ambient temperature. As a potential solution, additive manufacturing technologies, such as laser powder bed fusion, enable the production of metamaterial structures with complex local geometries that can be designed to achieve the desired thermal and mechanical behaviours. Recent advances enable the processing of multiple materials within a single build to achieve composite structural properties that are infeasible using conventional single materials. This study investigates the potential of tailoring the structural thermal expansion properties of several configurations of a multi-metal re-entrant lattice structure made of stainless steel 316L and the copper alloy CuCr1Zr. Unit cells and lattice structure segments with theoretical coefficients of thermal expansion ranging from 1.64 × 10−5 °C−1 to 2.51 × 10−5 °C−1 (16% more than CuCr1Zr) are evaluated by finite element analysis and validated experimentally. Imperfections related to the manufacturing process are shown to have a significant effect on net expansion. The results indicate good agreement despite the imperfections. The study demonstrates the feasibility of designing and fabricating metal lattice structures for a specific thermal expansion within, as well as above and below, the range of thermal expansion of the parent materials.

Biodegradable RF Metamaterial Perfect Absorber for Wireless Soil pH Monitoring

AbstractA wireless soil pH sensor is proposed using a sheet‐type perfect absorber metamaterial. The sensor utilizes a high‐impedance surface metamaterial, which functions as a perfect absorber at the resonant frequency. This sensor has a uniform water‐soluble Mg film at the bottom coated with hydroxyapatite that degrades depending on the pH, and a periodic square split ring resonator metamaterial structure made on top of a lossy dielectric plate. The sensor detects the dissolution of the metamaterial due to soil pH conditions through the electromagnetic wave reflection response at GHz frequency. Because of the perfect absorbing characteristics, the influence of soil on the metamaterial's electromagnetic response is blocked, allowing for robust measurement regardless of soil type. By coating the Mg with hydroxyapatite, the difference between acidic (pH = 3.0) and neutral soils can be detected by the time difference by a factor of three in the reflectance change from 40% to 75% reflectance change, indicating a transition from absorptive to reflective of the metamaterial's response, at the resonant frequency of 4.12 GHz.

Analyzing multilayer left-handed metamaterial optical waveguide structure with a localized arbitrary kerr-type nonlinear guiding film

Analyzing multilayer left-handed metamaterial optical waveguide structure with a localized arbitrary kerr-type nonlinear guiding film

Tensegrity‐Inspired Pre‐Stress Control for Programmable Multistability and Stiffness in Mechanical Metamaterials

AbstractMechanical metamaterials have considerable application potential, but are often limited to single applications owing to material and manufacturing constraints. To achieve a “single structure, multiple applications” goal, this study presents a multifunctional metamaterial structure. The metamaterial cells gain significant deformation and recovery abilities by incorporating the concept of a tensegrity structure to balance flexibility and rigidity and using a rigid‐flexible fabrication process. Inspired by cat‐tongue barbs and Hooke's law, an innovative pre‐stress programming structure is designed for integrated fabrication, enabling multilevel pre‐stress control for each cell. This programmable stress allows the twin‐cell array to transition in situ from monostable to bistable states and provides multilevel critical‐force functions for bistable states. After assembling a nine‐cell array, the structure offers a wide range of adjustable stiffness levels, enabling soft‐rigid transitions and varied force‐displacement responses without the need for additional tools. It also allows controlled collapse ratios and deformation through stiffness control. Additionally, the nine‐cell array features isotropy with a Poisson ratio of v = −1 and clear indentation resistance. This approach is promising for applications such as adjustable energy dissipators, automotive equipment, and passive safety.

Analysis of hyperbolic crystals with non-square lattice for improving acoustic energy harvesting

Abstract With the increase in the production of small and low-power electrical devices, there has been an increased focus on creating a useful power source to replace the battery. The energy contained in acoustic waves is one of the attractive energy sources for powering low-power devices. The design and fabrication of metamaterials is one of the effective methods of harvesting acoustic energy that has recently attracted the attention of many researchers. As is presented in this article, the aim is to design and fabricate a novel metamaterial structure with optimal dimensions to improve acoustic energy harvesting in a specific frequency range using a piezoelectric patch. In this metamaterial, hyperbolic crystals with non-square lattice have been used for the first time. This analysis is simulated using the 3D version of Comsol software 6.0. In addition, artificial neural networks and genetic algorithms were used to select the optimal parameters. The results showed that using the non-square lattice of the hyperbolic crystal, more average energy can be harvested in the frequency range of 3310-4325 Hz than in the metamaterial with the cylindrical crystal. Furthermore, the maximum amount of voltage and power extraction with an optimal electrical resistance of 10 kΩ in the metamaterial with the hyperbolic crystals at a frequency of 3374.71 Hz is equal to 27.26 mV and 74.33 nW, respectively, which is much larger compared to the metamaterial with the cylindrical crystals under the same mass and conditions. The simulation results are compared and validated with the experimental results by fabricating the present metamaterial and conducting laboratory tests.

Novel metamaterial wave barrier structure with multiple frequency wide band gaps for rail transit vibration isolation

As a new kind of artificial composite material, locally resonant phononic crystal (LRPC) can attenuate and suppress the propagation of elastic waves in certain frequency range, which has a broad application prospect and value in the field of vibration and noise control. The traditional LRPC can only open one band gap (BG), but the vibration and noise in practical engineering are often multi-band, so the traditional LRPC cannot effectively cover the target frequency range, and the efficiency of vibration and noise reduction is greatly limited. In response to the shortcomings of traditional LRPC, this paper designs a novel locally resonant phononic crystal with multiple primitive cell combination structure (LRPCWMPCCS), which is a locally resonant supercell structure composed of five types of locally resonant single primitive cells. Firstly, the band structure of the LRPCWMPCCS is calculated using the finite element method, and compared with the band structure of traditional LRPC. Secondly, the frequency response function of the LRPCWMPCCS is calculated to evaluate its attenuation effect on elastic waves in the BG frequency range, and the generation mechanism of its locally resonant BG is explored by analyzing the displacement field and energy distribution characteristics at the BG edge. Then, the equivalent model of the LRPCWMPCCS is established for theoretical calculation of the BG range. Finally, the vibration isolation performance of LRPCWMPCCS wave barrier in practical engineering is analyzed, and the application prospects of the LRPCWMPCCS are discussed. The results show that the LRPCWMPCCS designed in this paper can open the multifrequency BGs, and the BGs width is wider. The number of BGs opened is positively correlated with the type of primitive cells inside the LRPCWMPCCS. Within the BG frequency range, the LRPCWMPCCS has a good attenuation effect on vibration waves, with attenuation values exceeding 20 dB. The spring-mass system equivalent model of the LRPCWMPCCS can accurately calculate its BG range and has good accuracy. The LRPCWMPCCS wave barrier has remarkable control and attenuation effect on vibration. Among them, the maximum vibration acceleration of traditional LRPC wave barrier and LRPCWMPCCS wave barrier is reduced by 18.51% and 39.50%, respectively. The relevant research results of this paper have great value and prospects in the design of LRPC with multifrequency and wide BGs, which can also provide a new method and idea for solving vibration and noise problems.