Implementation Of Metamaterials Research Articles

Reconfigurable topological gradient metamaterials and potential applications

Elastic topological metamaterials are innovative fields of the fusion of physics and mechanics. Through novel microstructural designs, elastic topological metamaterials provide a pioneering approach to precisely manipulate elastic waves, maintaining robustness and efficiency in wave propagation even within complex environments. Recent advancements in reconfigurability and gradient features have significantly enriched the mechanical phenomena of wave manipulation, broadening the application potential of elastic topological metamaterials. In this study, we design the local resonant phononic crystal, employing a spiral support structure to ensure low-frequency characteristics and adjustable mass for flexible configuration. By utilizing the designed lattices with distinct topological phases, the topological valley edge states are constructed. The frequency and group velocity variation of the topological edge states under different stiffness and mass parameters are analyzed. Furthermore, we further constructed the mass and stiffness gradient metamaterial to analyze the transmission law of elastic waves in topological metamaterials. Additionally, the fluctuation features of the wave transmittance under disordered and impurity defects were discussed, confirming the robustness of waveguides within low-frequency topological metamaterials. Finally, we explored the potential applications of the designed metamaterials in energy localization and low-frequency reconfigurable waveguides. Numerical analysis showed that the topological gradient metamaterials can enhance the vibration energy at a specific interface, and low-frequency bend waveguide paths can be adjusted flexibly by configurable mass. In summary, this paper focuses on the low-frequency and gradient features of elastic topological metamaterials, aiming to unlock their application potential in vibrational energy harvesting, vibration suppression, and information transmission, which accelerate the practical implementation of topological metamaterials.

Crafting shape-changing experiences: emotional evaluation of morphing metamaterials

ABSTRACT We introduce a novel approach to evaluate how the design properties of morphing metamaterial influence shape-changing experiences. We leverage parametric design to create cutting patterns that change the Density and Geometry material properties. Using laser-cutting, we apply the patterns to a non-stretchable woven textile, resulting in a stretchable metamaterial that we actuate using an electromagnetic coil. This systematic design approach leads to programmatic control over the material movement, making it suitable for controlled evaluation of perceived experience. In a 2×2 mixed-method study, we assess how the metamaterial’s Density and Geometry properties impact the observed experience. Our findings indicate that such changes significantly and independently affect participants’ perceived emotions, mood, associations, and preferences. Our research contributes to the body of work of systematic studies in the shape-changing community. By using our morphing metamaterial design and implementation technique, coupled with our controlled evaluation of specific design properties, we have revealed new insights about the influencing factors of shape-changing experiences. We have incorporated these insights into our morphing metamaterial design guidelines, which outline the impact of Density and Geometry properties on an observer’s perceived emotions. We hope our work will open up new possibilities for expressive, evocative metamaterial-focused shape-changing experiences.

Electromagnetic metamaterials for biomedical applications: short review and trends

This mini-review examines the most prominent features and usages of metamaterials, such as metamaterial-based and metamaterial-inspired RF components used for biomedical applications. Emphasis is given to applications on sensing and imaging systems, wearable and implantable antennas for telemetry, and metamaterials used as flexible absorbers for protection against extreme electromagnetic (EM) radiation. A short discussion and trends on the metamaterial composition, implementation, and phantom preparation are presented. This review seeks to compile the state-of-the-art biomedical systems that utilize metamaterial concepts for enhancing their performance in some form or another. The goal is to highlight the diverse applications of metamaterials and demonstrate how different metamaterial techniques impact EM biomedical applications from RF to THz frequency range. Insights and open problems are discussed, illuminating the prototyping process.

High Gain Metamaterial Implemented Antenna Design with Circular Polarization for mm-Wave 5G and 6G Sub-THz Communication

A high-gain metamaterial-enabled circularly polarized antenna has been proposed. Two patch structures patch A and patch B have been designed by using different shape slots. After slot etching on the patch, two different metamaterial techniques were used. Circular metamaterial (MTM) was implemented for Patch A, while rectangular MTM was used for Patch B. The implementation of MTM resulted in increased antenna gain, as well as improvements in impedance bandwidth RL and AR. So, in the proposed article two antenna structures ANT-A and ANT-B, are presented. The maximum gain achieved for ANT-A is 34.759dBi, covering the frequency bands (28.997-202.113) GHz, and (205.884-336.693) while in the case of ANT-B, it is 36.3155dBi, covering the frequency bands (29.178-330.490) GHz, and (334.936-336.702) GHz. The proposed antenna structure is a useful design for mm-wave 5G and 6G Sub-THz communications.

Feynman’s method in chiral nanorod-based metamaterial nanoplasmonics

We propose a theoretical approach to some of the nanorod-based metamaterial implementations that does not depend on macroscopic electrodynamics. The approach is motivated by the fact that in actual experiments the incident electromagnetic wave encounters a metamaterial structure which is planar in its shape, contains a layer or two of artificially created building blocks, and therefore cannot be regarded as a three-dimensional continuous medium. This leads to a theoretical framework in which the phenomenological concept of refractive index loses its principled meaning, and the deeper concept of scattering is taking center stage. Our proposal and its mathematical realization rely heavily on Feynman’s explanation of the physical origin of the index of refraction and on his formula for the field of a plane of oscillating charges. We provide a complete proof of Feynman’s formula, filling in some steps that were missing in the original derivation, and then generalize it to the case of a finite disk, which may be relevant to the actual experiments involving laser beams. We then show how the formula can be applied to metamaterial nanoplasmonics by considering some subtle interference effects in uniform laser beams striking metamaterial plates. The first two effects use a single layer of aligned plasmonic nanorods, while the third uses a single layer of gyrotropic elements that may conveniently be described by the celebrated Born-Kuhn oscillator model. The considered effects can potentially be used in the development of quality standards for various metamaterial devices.

Transverse magnetic mode waveguide switches employing metal and negative index metamaterial loads

Abstract A compact optical switch concept based on moving a negative-index media (NIM) load is extended here to include waveguides carrying transverse magnetic (TM) modes. Many current metamaterial NIM implementations work with TM waves. Simulations show that with a current metamaterial NIM implementation switching is possible for TM modes. The simulated switch structure is based on an optical waveguide coupler made by a commercial foundry process. The NIM load is realized above the waveguides in a post foundry micro-electro mechanical systems (MEMS) layer. Metal loads are also shown to be suitable for switching TM modes. However, only NIM loads can in theory permit simultaneous switching of both transverse electric and TM modes.

Extending the Linearity of AlScN Contour-Mode Resonators Through Acoustic Metamaterials-Based Reflectors.

This work describes the implementation of acoustic metamaterials (AMs) made of a forest of rods at the sides of a suspended aluminum scandium nitride (AlScN) contour-mode resonator (CMR) to increase its power handling without causing degradations of its electromechanical performance. The increase in usable anchoring perimeter with respect to conventional CMR designs, enabled by the adoption of two AM-based lateral anchors, permits to achieve improved heat conduction from the resonator's active region to the substrate. Furthermore, thanks to such AM-based lateral anchors' unique acoustic dispersion features, the attained increase of anchored perimeter does not cause any degradations of the CMR's electromechanical performance, even leading to a ~15% improvement in the measured quality factor. Finally, we experimentally show that using our AM-based lateral anchors leads to a more linear CMR's electrical response, which is enabled by a 32% reduction of its Duffing nonlinear coefficient with respect to the corresponding value attained by a conventional CMR design that uses fully etched lateral sides.

Miniaturized MIMO antenna design based on octagonal-shaped SRR metamaterial for UWB applications

A miniaturized antenna based on octagonal-shaped split ring resonator (O-SRR) metamaterial and CPW-feeder technique for ultra-wideband (UWB) applications is developed in this research. The structure of the component cell monopole antenna is designed by using a triangle-shaped fractal method and merging metamaterial implementation with the L-stub shape. These techniques provide a wide impedance bandwidth for the innovative wireless antenna, which operates from 2.46 to 13.98 GHz. The planned module cell dimensions are 20 by 16 square millimetres (0.164λL×0.131), where the wavelength (λL) is 121.95 mm. This low-profile antenna has then been employed to design an array of 2 × 2 Multi Input Multi Output (MIMO) antennas with an overall size of 20 × 34 mm2. Two symmetric antennas are arranged in the designed miniaturized MIMO system with an inverted T-shaped decoupling copper between them. Measurement results show that the dual antenna with multiple diversity metrics has great characteristics for MIMO applications due to providing low mutual coupling value, lower than 0.30 bits per s. /Hz of channel capacity loss, minor envelope correlation coefficient of fewer than 0.003, lower −10 dB of total active reflection coefficient, greater than 9.96 dB of diversity gain and proper mean effective gain (MEG ratio ≈ 1, MEG ≤ 0.5). A high peak gain magnitude of 5.71 dBi is provided at an operating frequency of 13.2 GHz for the recommended single antenna.

Scattering at Temporal Interfaces: An overview from an antennas and propagation engineering perspective

Recent years have witnessed a surge of interest in exotic electromagnetic (EM) wave propagation in time-varying systems. An interesting concept is the one of a temporal interface, the time-analogue of a spatial interface, formed by an abrupt and uniform change of the EM properties of the host medium in time. A time interface scatters the incident wave in a dual fashion compared to its spatial counterpart, conserving momentum but transforming frequency and exchanging energy with the wave. This article provides an overview of the wave-scattering features induced by time interfaces from an antennas and propagation engineering perspective. We first discuss the dualities of wave propagation across spatial and temporal interfaces, by recasting the telegrapher equations in a linear time-variant (LTV) transmission line (TL). Then, we introduce the scattering matrix to describe temporal scattering processes, and derive the conditions for reciprocity and momentum conservation. Understanding temporal scattering through the lens of conventional microwave engineering theory may facilitate the analysis and implementation of next-generation metamaterials encompassing temporal degrees of freedom.

Cascaded parametric amplification based on spatiotemporal modulations

Active devices have drawn considerable attention owing to their powerful capabilities to manipulate electromagnetic waves. Fast and periodic modulation of material properties is one of the key obstacles to the practical implementation of active metamaterials and metasurfaces. In this study, to circumvent this limitation, we employ a cascaded phase-matching mechanism to amplify signals through spatiotemporal modulation of permittivity. Our results show that the energy of the amplified fundamental mode can be efficiently transferred to that of the high harmonic components if the spatiotemporal modulation travels at the same speed as the signals. This outstanding benefit enables a low-frequency pump to excite parametric amplification. The realization of cascaded parametric amplification is demonstrated by finite-difference time-domain (FDTD) simulations and analytical calculations based on the Bloch–Floquet theory. We find that the same lasing state can always be excited by an incidence at different harmonic frequencies. The spectral and temporal responses of the space-time modulated slab strongly depend on the modulation length, modulation strength, and modulation velocity. Furthermore, the cascaded parametric oscillators composed of a cavity formed by photonic crystals are presented. The lasing threshold is significantly reduced by the cavity resonance. Finally, the excitation of cascaded parametric amplification relying on the Si-waveguide platform is demonstrated. We believed that the proposed mechanism provides a promising opportunity for the practical implementation of intense amplification and coherent radiation based on active metamaterials.

Metasurfaces for Sensing Applications: Gas, Bio and Chemical

Performance of photonic devices critically depends upon their efficiency on controlling the flow of light therein. In the recent past, the implementation of plasmonics, two-dimensional (2D) materials and metamaterials for enhanced light-matter interaction (through concepts such as sub-wavelength light confinement and dynamic wavefront shape manipulation) led to diverse applications belonging to spectroscopy, imaging and optical sensing etc. While 2D materials such as graphene, MoS2 etc., are still being explored in optical sensing in last few years, the application of plasmonics and metamaterials is limited owing to the involvement of noble metals having a constant electron density. The capability of competently controlling the electron density of noble metals is very limited. Further, due to absorption characteristics of metals, the plasmonic and metamaterial devices suffer from large optical loss. Hence, the photonic devices (sensors, in particular) require that an efficient dynamic control of light at nanoscale through field (electric or optical) variation using substitute low-loss materials. One such option may be plasmonic metasurfaces. Metasurfaces are arrays of optical antenna-like anisotropic structures (sub-wavelength size), which are designated to control the amplitude and phase of reflected, scattered and transmitted components of incident light radiation. The present review put forth recent development on metamaterial and metastructure-based various sensors.

Recent progress in terahertz metamaterial modulators

Abstract The terahertz (0.1–10 THz) range represents a fast-evolving research and industrial field. The great interest for this portion of the electromagnetic spectrum, which lies between the photonics and the electronics ranges, stems from the unique and disruptive sectors where this radiation finds applications in, such as spectroscopy, quantum electronics, sensing and wireless communications beyond 5G. Engineering the propagation of terahertz light has always proved to be an intrinsically difficult task and for a long time it has been the bottleneck hindering the full exploitation of the terahertz spectrum. Amongst the different approaches that have been proposed so far for terahertz signal manipulation, the implementation of metamaterials has proved to be the most successful one, owing to the relative ease of realisation, high efficiency and spectral versatility. In this review, we present the latest developments in terahertz modulators based on metamaterials, while highlighting a few selected key applications in sensing, wireless communications and quantum electronics, which have particularly benefitted from these developments.

An Approach for Active Acoustic Metamaterial Design Implementation and Analysis

An Approach for Active Acoustic Metamaterial Design Implementation and Analysis

Transmission line modeling of metamaterial for different fractional band width

Metamaterials are generally considered as artificially electromagnetic structures with unusual properties which are not readily available in nature. The metamaterial implementation for the specified transition frequency is always considered as a challenge. In this study, the circuit modeling of the double negative metamaterial is investigated for left and right hand behavior of the wave propagations. Moreover the theory is also evaluated for different fractional bandwidth of the materials. The model is evaluated for negative characteristics of refractive index and dispersion. The design is evaluated for balanced and unbalanced conditions using the transmission line theory. The circuit modeling is simulated and analyzed using MATLAB.

Experimental Demonstration of Thermal Chameleonlike Rotators with Transformation-Invariant Metamaterials

Intelligent metamaterials have aroused intensive research interest due to their adaptive responses to environmental changes. However, existing transformation-thermotics-based metamaterials have almost no intelligence because their parameters are crucially dependent on environmental parameters. Therefore, once the environment changes, these thermal metamaterials can no longer work, which limits practical applications. To solve the problem, we propose a mechanism for intelligent thermal metamaterials based on transformation-invariant metamaterials. As an application, we design intelligent thermal rotators, which can guide the direction of heat flux with different environmental parameters. Since the adaptive behavior is similar to chameleons, the present rotators are also called chameleonlike rotators. We further perform finite-element simulations and laboratory experiments to validate the scheme, and the chameleonlike behavior is clearly demonstrated. These results have potential applications for the implementation of adaptive and adjustable thermal metamaterials. Similar behaviors can also be expected in other fields like hydrodynamics.

An efficient wideband low noise amplifier (WLNA) using advanced design system based industrial micro strip antenna

An efficient architecture to design low noise amplifier methods aimed at reducing the radar cross-section (RCS) under the X - and Y-polarizations with incident waves, the characteristics of radiation has been analyzed. The goal is to carry out the Polarization Conversion Meta Material (PCM) implementation and passive cancelation policy. The Low-Noise Amplifier (LNA) supports the use of multi-stable applications being the front end of any micro strip antenna with the need for a multiband receiver is very high in technology development. This LNA design requires the synchronization of a single device frequency of a different device. So researchers work on developing a Wideband Low noise Amplifier (WLNA) with the wideband receiver. An LNA radio receiver from the mainstream is that the subsequent stages of the signal are lossless and the low noise rate has the highest gain. LNA design is an important task for the proper management of trade between all parameters of it, including gain, noise, stability, and power consumption. Advanced Design System (ADS) software is used to design and simulated the proposed micro strip antenna with LNA. The proposed micro strip antenna is to be fabricated using the Fr4 substrate and investigated by simulation and measurements like radiation patterns, S-parameters and return loss by using Advanced Design System software to improve the existing System.

Development of 3D boundary element method for the simulation of acoustic metamaterials/metasurfaces in mean flow for aerospace applications

Low-cost airlines have significantly increased air transport, thus an increase in aviation noise. Therefore, predicting aircraft noise is an important component for designing an aircraft to reduce its impact on environmental noise along with the cost of testing and certification. The aim of this work is to develop a three-dimensional Boundary Element Method (BEM), which can predict the sound propagation and scattering over metamaterials and metasurfaces in mean flow. A methodology for the implementation of metamaterials and metasurfaces in BEM as an impedance patch is presented here. A three-dimensional BEM named as BEM3D has been developed to solve the aero-acoustics problems, which incorporates the Fast Multipole Method to solve large scale acoustics problems, Taylor’s transformation to account for uniform and non-uniform mean flow, impedance and non-local boundary conditions for the implementation of metamaterials. To validate BEM3D, the predictions have been benchmarked against the Finite Element Method (FEM) simulations and experimental data. It has been concluded that for no flow case BEM3D gives identical acoustics potential values against benchmarked FEM (COMSOL) predictions. For Mach number of 0.1, the BEM3D and FEM (COMSOL) predictions show small differences. The difference between BEM3D and FEM (COMSOL) predictions increases further for higher Mach number of 0.2 and 0.3. The increase in difference with Mach number is because Taylor’s Transformation gives an approximate solution for the boundary integral equation. Nevertheless, it has been concluded that Taylor’s transformation gives reasonable predictions for low Mach number of up to 0.3. BEM3D predictions have been validated against experimental data on a flat plate and a duct. Very good agreement has been found between the measured data and BEM3D predictions for sound propagation without and with the mean flow at low Mach number.

Electromagnetism, axions, and topology: A first-order operator approach to constitutive responses provides greater freedom

We show how the standard constitutive assumptions for the macroscopic Maxwell equations can be relaxed. This is done by arguing that the Maxwellian excitation fields (D,H) should be dispensed with, on the grounds that they (a) cannot be measured, and (b) act solely as gauge potentials for the charge and current. In the resulting theory, it is only the links between the fields (E,B) and the charge and current (\rho,J) that matter; and so we introduce appropriate linear operator equations that combine the Gauss and Maxwell-Ampere equations with the constitutive relations, eliminating (D,H). The result is that we can admit more types of electromagnetic media -- notably, the new relations can allow coupling in the bulk to a homogeneous axionic material; in contrast to standard EM where any homogeneous axion-like field is completely decoupled in the bulk, and only accessible at boundaries. We also consider a wider context, including the role of topology, extended non-axionic constitutive parameters, and treatment of Ohmic currents. A range of examples including an axonic response material is presented, including static electromagnetic scenarios, a possible metamaterial implementation, and how the transformation optics paradigm would be modified. Notably, these examples include one where topological considerations make it impossible to model using (D,H).

Review of Metasurface Antennas for Computational Microwave Imaging

This article covers recent advances in the fusion of metasurface antenna design and computational imaging (CI) concepts for the realization of imaging systems that are planar, fast, and low cost. We start by explaining the operation of metamaterial antennas which can generate diverse radiation patterns. Their advantages and distinctions from previous antennas are elucidated. We then provide an intuitive overview of the CI framework and argue that metamaterial antennas are a near ideal platform for implementing such schemes at microwave frequencies. We describe two metamaterial antenna implementations: frequency diverse and electronically reconfigurable. The tradeoffs governing the design and operation of each architecture are examined. We conclude by examining the outlook of metamaterial antennas for microwave imaging and propose various future directions.

Ground Plane Metamaterial Inspired Patch Antenna For L-Band Applications

The patch antennas are very popular and useful antennas for small charge and solid design for RF uses and WiFi systems. In Wi-Fi cellular phone call and satellite uses, patch antennas has magnetized a lot interest because of less dimension, cheap on mass production, less burden, short profile and simple incorporation with other parts. In this paper a new design of metamaterial technique is proposed with the patch antenna to modify its parameters. Antenna was designed at 1.9GHz and analyzed later to enhance its parameters and mainly bandwidth and Gain of the antenna, metamaterial was implemented. The coupling of patch and ground along with the metamaterial implementation on the ground plane made the bandwidth and Gain enhanced.