Electromagnetic Waves Research Articles

Hierarchically Structured Composite Decorated with Core-Sheath CoC@Carbon Fiber Felt: Exceptional Electromagnetic Interference Shielding and Applications in Thermal Management and Electro/Photo-Thermal Conversion.

In the microelectronics era, electromagnetic radiation and heat accumulation in electronic devices are urgent challenges requiring solutions, particularly through the use of structure-function integrated and lightweight materials for electromagnetic interference (EMI) shielding and thermal management. Hierarchically structured polyether-ether-ketone-based composites are prepared in this study by in situ deposition and dip coating using a simple and scalable method. Magnetic cobalt nanoparticles derived from magnetic metal-organic frameworks are deposited on carbon fiber felt featuring a macroscopic continuous conductive network. Next, a hybrid slurry is applied to connect the isolated fibers, which bridge the fiber gaps to create new electron and phonon transport channels, increasing the thermal conductivity (23.43 Wm-1K-1 in plane, 4.84 Wm-1K-1 through plane) for efficient heat dissipation. Owing to the stable 3D crosslinked network with high electrical conductivity (13608 Sm-1), the composite offers ultra-high EMI shielding in the X-band (101.64dB with stability in extreme environments), excellent Joule heating performance (220°C at 4V), and excellent photothermal conversion (94°C at 500 mWcm-2). This multifunctional composite material has great application prospects in precision electronic equipment.

Simple THz Phase Retarder Based on Mach–Zehnder Interferometer for Polarization Control

Abstract On-demand polarization control of electromagnetic waves is the fundamental element of modern optics. Its interest has recently been expanded in the terahertz (THz) range for coherent excitation of collective quasiparticles in matters, triggering a wide variety of non-trivial intriguing physics, e.g., anharmonicity, nonlinear coupling, and metastability. Wavelength tunability in THz polarization control is fundamentally important for the resonant excitation of collective modes. Here, we propose and demonstrate a simple and convenient THz phase retarder based on the Mach–Zehnder interferometer to obtain circular polarization. The efficiency of THz polarization conversion is demonstrated by the achieved high polarization degree of more than 99.9% and a large transmission of ~ 76%. The simple setup allows us to adapt the phase retarder to existing setups readily and will contribute to further exploration of ultrafast science, e.g., chiral phononics.

Abstract 1302: A practical method of delivering induced electric field (iEF) therapy

Abstract Among non-pharmacological treatments, induced electric field (iEF) therapy is the only bioelectric approach that is truly contact-free and non-invasive. In iEF treatment, the permeability of magnetic fields varying in time is exploited to induce electric fields inside cells and tissues without the need for electrodes or adhesive contact with the skin. Induced electric fields are a non-ionizing form of electromagnetic radiation demonstrated to have strong anti-metastasis and anti-tumor activity in vitro and in vivo against triple negative breast cancer (TNBC), including significant host immune response in a pre-clinical animal model. Moreover, combination treatment of MDA-MB-231 and MDA-MB-468 cells with standard of care chemotherapeutic agents (paclitaxel, capecitabine) plus iEF in vitro, significantly improve their anti-viability and anti-proliferation activity (half-maximal inhibitory concentrations or IC50 values decreased by ∼50% for both paclitaxel+iEF and capecitabine+iEF treatments). EMBioSys has developed technology translating iEF therapy into clinical treatment and delivered in the form of wearable, washable garments such as camisoles. Special conducting threads integrated into the camisole enable a current to be driven through the insulated threads at voltages less than 10 Volts. The time-varying current generates a temporally varying magnetic induction within the space enclosed by the camisole and generates iEFs by Faraday’s law. We measured the magnetic inductions, compared with their calculated values, and determined iEF distributions within the space enclosed by the garment. We find that iEF intensities found to have anti-metastasis and anti-tumor effects in animal models of TNBC can be easily attained at human anatomical scales and delivered in a practical manner for use by patients. Our work lays the foundation for first in human studies by extending a treatment developed in the laboratory into a wearable and washable treatment device for cancer patients. Citation Format: Joseph West, Christopher Barron, Vish Subramaniam. A practical method of delivering induced electric field (iEF) therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1302.

Sensing Gravity with Polarized Electromagnetic Radiation

Sensing Gravity with Polarized Electromagnetic Radiation

Review of UAV based on Reconfigurable Intelligent Surface and ISAC

This paper discusses the application of Reconfigurable Intelligent Surface (RIS) technology combined with Unmanned Aerial Vehicle (UAV) technology, and discusses their innovative potential in 6G communication networks. Especially in the field of Integrated Sensing and Communication (ISAC) application prospects. RIS is a two-dimensional surface based on electromagnetic metamaterial technology. Through dynamic regulation of electromagnetic units, parameters such as phase and amplitude of incident electromagnetic waves can be flexibly controlled, so as to optimize wireless channel and improve communication performance. Compared with traditional communication systems, RIS has the advantages of low cost, low power consumption and easy deployment, which can significantly improve the stability and coverage of UAS communication links. Through in-depth analysis of the working principle, hardware architecture and advantages of RIS combined with UAV, this paper elaborates its application scenarios in UAV network, including disaster relief, urban management, intelligent transportation and battlefield reconnaissance. With RIS’s intelligent beamforming and channel optimization, UAVs can not only provide efficient communication services, but also enable accurate environment awareness and target tracking. In addition, this paper analyzes the key challenges faced by RIS-assisted UAVs in practical engineering applications, such as the complexity of channel estimation, multi-UAV cooperative communication, and adaptability in dynamic environments. By proposing several solutions, including optimizing channel estimation technology and improving beamforming design, this paper provides theoretical basis and technical support for the wide application of RIS and UAV in 6G networks in the future. The research shows that the introduction of RIS technology will greatly improve the communication ability of UAVs in complex environments, and promote the integration of communication and perception in the 6G era.

Fabrication and application of 3D Terahertz metamaterials with vertical multinanogaps for spectroscopic sensing

Terahertz (THz) metamaterials have garnered attention for their unique electromagnetic properties and potential applications in biomaterial sensing, offering label-free, non-contact capabilities. However, their performance is limited by their diffraction limits, impeding the detection of small objects. This study presents an approach for fabricating three-dimensional (3D) THz metamaterials with vertically oriented, high-aspect-ratio multinanogaps. These 3D metamaterials comprise laminated cross-shaped metal layers, which induce electromagnetic resonance, and polymer layers that support the metal layers at the center of the cross shape. Air nanogaps formed between metal layers achieved aspect ratios of > 64. Conventional microfabrication techniques were employed, including spin coating, metal sputtering deposition, photolithography, ion milling etching, and oxygen plasma etching, without relying on electron beam lithography. Spectroscopic analyses of the fabricated metamaterials revealed that the multilayered structure exhibited a deeper dip than single-layered and double-layered configurations. To validate THz sensing, we used isopropyl alcohol (IPA) for THz spectroscopy applications; the spectra indicated significant peak frequency shifts in the transmission dip of the fabricated device with and without IPA. These findings highlight the application scope of the as-prepared 3D THz metamaterial in material sensing techniques, enhancing THz-metamaterial-based device performance.

Triplet J-Driven DNP─A Proposal to Increase the Sensitivity of Solution-State NMR without Microwave.

Dynamic nuclear polarization (DNP) is an important method to enhance the limited sensitivity of nuclear magnetic resonance (NMR). Using the existing mechanisms such as Overhauser DNP (ODNP) is still difficult to achieve significant enhancement of NMR signals in solutions at a high magnetic field. The recently proposed J-driven DNP (JDNP) condition (when the exchange interaction Jex of two electron spins matches the electron or the nuclear Larmor frequency ωE and ωN) may enable signal enhancement in solution as it requires only dipolar interaction between the biradical polarization agent and the analyte. However, likewise ODNP, the current JDNP strategy still requires the saturation of the electron polarization with high microwave power which has poor penetration and is associated with heating effects in most liquids. The replacement of high-power microwave irradiation is possible if the temporal electron polarization imbalance is created by an electron electromagnetic (EM) irradiation at different wavelengths such as the visible light. Here, we propose a triplet-JDNP mechanism which first exploits the light-induced singlet fission process (i.e., a singlet exciton is converted into two triplet excitons). As the JDNP condition Jex ≈ ± ωE is fulfilled, a triplet-to-triplet cross-relaxation process will occur with different rates and consequently lead to the creation of hyperpolarization on the coupled nuclear spin states. This communication discusses the theory behind the triplet-JDNP proposal, as well as the polarizing agents and conditions that will enable the new approach to enhance NMR's sensitivity without the need of microwave irradiation.

Radiofrequency Transparent Uniaxial Dual‐Polarized Metasurface with Ultrawide Brewster Angle Stability

AbstractElectromagnetic (EM) selective structures with high transmission and ultrawide angular coverage are essential for applications ranging from military fields, such as high‐speed aircraft, to civilian domains, such as 5G communications, enabling omnidirectional spatial EM information perception. However, traditional EM selective structures suffer from increasingly severe characteristic impedance mismatches under the large‐angle oblique incidence of EM waves. To overcome this dilemma, a polarization‐insensitive uniaxial dielectric‐magnetic metasurface is proposed with ultrawide Brewster angle stability to realize perfect radiofrequency transparency. It is theoretically demonstrated that a uniaxial dielectric‐magnetic slab can exhibit ultra‐wide‐angle transmission properties while maintaining polarization insensitivity. As a proof of concept, a uniaxial dielectric‐magnetic metasurface structure is designed, fabricated, and measured to simultaneously achieve wide‐band and wide‐angle radiofrequency transparency phenomena with transverse electric and transverse magnetic polarization responses. This study fundamentally resolves the theoretical challenge of characteristic impedance mismatch in traditional EM surfaces under large‐angle oblique incidence, achieving an unprecedented realization of ultrawide angular, high‐efficiency transmission for arbitrarily polarized electromagnetic waves.

ОПРЕДЕЛЕНИЕМЕТРОНИДАЗОЛА В СТОМАТОЛОГИЧЕСКИХ ПЛЕНКАХ МЕТОДОМ ДИФФЕРЕНЦИАЛЬНОЙ СПЕКТРОФОТОМЕТРИИ

Treatment and prevention of oral diseases remain one of the most important tasks of modern dentistry. The complexity of the clinical manifestations of these diseases often makes it difficult to select the optimal drug therapy. Moreover, in addition to choosing a drug that corresponds to the etiology and pathogenesis of the disease, its compliance with modern pharmacokinetic requirements is also important. In the context of the treatment of various diseases of the oral cavity, the choice of the appropriate dosage form plays a crucial role. In addition to widely known and actively used forms of drugs (tablets, solutions, gels, etc.), dental films are of particular importance.A dental film containing metronidazole was created at the Pyatigorsk Medical and Pharmaceutical Institute, and therefore the task was to develop methods for standardizing this dosage form. To quantify metronidazole in the developed films, we used the method of ultraviolet spectrophotometry, which is widely used in the analysis of medicines and is one of the simplest and most accurate methods. However, when using the spectrophotometric method in the analysis of dosage forms, the presence of concomitant substances capable of absorbing electromagnetic radiation at the selected analytical wavelength should be taken into account, which may affect the results of the analysis. In order to assess the effect of concomitant substances (mumie, MC-8, plasdon VA-64, cremophor CO-40, propylene glycol, etc.) on the absorption of metronidazole, we measured their UV spectra in the range of 225 – 390 nm.Since the pH value can affect the location of absorption maxima and cause them to shift towards longer or shorter wavelengths, the effect of pH on the spectral characteristics of aqueous solutions of metronidazole was studied. The possibility of using differential spectrophotometry in the ultraviolet region for the quantitative determination of metronidazole in dental films has been established. A method of determination has been developed and its validation assessment has been carried out.

Generation of Neutron Airy Beams

The Airy wave packet is a solution to the potential-free Schrödinger equation that exhibits remarkable properties such as self-acceleration, nondiffraction, and self-healing. Although Airy beams are now routinely realized with electromagnetic waves and electrons, the implementation with neutrons has remained elusive due to small transverse coherence lengths, low fluence rates, and the absence of neutron lenses. In this Letter, we overcome these challenges through a holographic approach and present the first experimental demonstration of neutron Airy beams. The presented techniques pave the way for fundamental physics studies with Airy beams of nonelementary particles, the development of novel neutron optics components, and the realization of neutron Airy-vortex beams. Published by the American Physical Society 2025

The effects and mechanisms of Far-infrared ray on depression-like behavior induced by CRS in mice.

Far-infrared ray (FIR) is an electromagnetic wave known to impart health benefits against various pathophysiological conditions, including diabetes mellitus, renocardiovascular disorders, stress, and depression, among others. However, the precise impact of FIR on major depressive disorder (MDD) and the underlying molecular mechanisms remain unclear. Here, we aimed to investigate the effects and elucidate the molecular mechanisms of FIR on depression-like behavior in mice. A mouse model of depression was established using chronic restraint stress (CRS). Behavioral tests were performed to assess alterations in depression-like behaviors. Biochemical methods were employed to measure the levels of IL-1β, IL-6, TNF-α, S100β, IL-17, melatonin (MT), 5-hydroxytryptamine (5-HT), glutathione (GSH), malondialdehyde (MDA), brain-derived neurotrophic factor (BDNF), and corticosterone (CORT) in mice serum. Similarly, the levels of IL-1β, IL-6, TNF-α, S100β, IL-17, and MT in mice brains were measured using biochemical methods. Hematoxylin-eosin and Nissl staining were utilized to detect morphological changes in the mice hippocampus. In addition, the structure and mitochondrial morphology of hippocampal neurons and microglia were studied using transmission electron microscopy (TEM). The results of behavioral tests revealed that FIR mitigated the depression-like behaviors induced by CRS. FIR also reversed the levels of IL-1β, IL-6, TNF-α, and related cytokines in the periphery and brain. The results of hematoxylin-eosin and Nissl staining showed that FIR improved the damage of mice's hippocampus. Additionally, TEM revealed that FIR alleviated the damage of CRS to hippocampal neurons and microglia. Our findings suggest that FIR can ameliorate depression-like behavior induced by CRS in mice. FIR can reverse the levels of related cytokines in the periphery and brain, and alleviate damage to neurons and microglia, which may constitute its underlying molecular mechanism.

Comprehensive Utilization of Borehole AFET and Logging Method Detecting Goaf Area in Coal Mines

China, as the world's largest coal producer and consumer, faces increasingly severe challenges from coal mine goaf areas formed through decades of intensive mining. These underground voids, resulting from exhausted resources or technical limitations, not only cause environmental issues like land subsidence and groundwater contamination but also pose critical safety risks for ongoing mining operations, including water inrushes, gas outbursts, and roof collapses. Conventional geophysical methods such as seismic surveys and electromagnetic detection demonstrate limited effectiveness in complex geological conditions due to susceptibility to electrical heterogeneity, electromagnetic interference, and interpretation ambiguities.This study presents an innovative integrated approach combining the Audio-Frequency Electrical Transillumination (AFET) method with multi-parameter borehole logging to establish a three-dimensional detection system. The AFET technique employs 0.1-10 kHz electromagnetic waves to identify electrical anomalies associated with goafs, enabling extensive horizontal scanning. This is complemented by vertical high-resolution profiling through borehole measurements of resistivity, spontaneous potential, and acoustic velocity. Field applications in Shanxi Province's typical coal mines achieved breakthrough results: Using a grid-drilling pattern (15m spacing, 300m depth), the method successfully detected three concealed goafs missed by conventional approaches, with spatial positioning errors under 0.5m. Notably, it accurately identified two un-collapsed water-filled cavities. This surface-borehole synergistic approach overcomes single-method limitations, enhancing goaf detection accuracy to over 92%. The technique provides reliable technical support for safe mining practices and represents significant progress in precise detection of hidden geological hazards in Chinese coal mines, offering valuable insights for global mining geophysics.

Multi-Object Feature Extraction in Resonance Region Based on Short-Time Matrix Pencil Method

As an intrinsic characteristic of the target, the pole characteristic of the resonant region is solely determined by the target itself and remains invariant with respect to external factors such as the incident direction and polarization of electromagnetic waves. Consequently, it serves as a critical foundation for target identification. The Matrix Pencil Method (MPM) is currently a widely adopted technique for extracting target poles; however, it typically processes single targets. When multiple targets produce time-domain echoes in the echo signal, the MPM fails to distinguish between individual targets, leading to extracted pole information that does not adequately represent the relevant characteristics of each target. In this paper, we propose a Short-Time Matrix Pencil Method (STMPM), which introduces sliding time windows to differentiate multiple targets in time-domain echoes. By analyzing the variations in poles across each sliding time window, the STMPM can accurately extract the poles corresponding to each target.

Anisotropy of Voltage Sensitivity of Bow-Tie Microwave Diodes Containing 2DEG Layer

Microwave Bow-Tie Diodes operate across a broad frequency range, including THz radiation detection and THz imaging applications. When fabricated using modulation-doped structures, these diodes exhibit enhanced detection properties that are best characterized by voltage sensitivity. The sensitivity is influenced by multiple factors, including diode design, semiconductor material quality, and the characteristics of the ohmic contacts. In this study, we examine how the electrical properties of modulation-doped bow-tie diodes are affected by their orientation relative to the crystallographic axes. Extensive investigations on various bow-tie diodes exposed to broadband microwave radiation, both in darkness and under white and infrared light illumination, enabled us to identify the optimal diode designs and illumination conditions for maximizing sensitivity to electromagnetic radiation. Based on our findings, we provide recommendations for diode design and illumination conditions to enhance the diode’s sensitivity to microwave radiation while minimizing illumination-induced effects on electrical properties.

Design of a Polarization-Insensitive and Wide-Angle Triple-Band Metamaterial Absorber

This paper proposes a tri-band wide-angle polarization-insensitive absorber operating in the C-band and Ku-band, based on the design concept of metal–dielectric–metal. The absorber achieves absorption efficiencies of 99.05%, 99.3%, and 97.9% at 4.23 GHz, 7.403 GHz, and 14.813 GHz, respectively. The first two absorption frequencies are in the C-band, while the third absorption frequency is in the Ku-band, both of which are commonly used in satellite communication. The designed absorber consists of three differently sized regular hexagonal rings. To analyze the interaction mechanism between the electromagnetic wave and the absorber, we applied the theory of impedance matching and equivalent media to analyze the metamaterial properties of the absorber. In addition, the equivalent circuit model of the absorber has been analyzed. We then determined the existence of coupled electromagnetic resonances between the top and bottom surfaces by analyzing the distribution of the electric field, magnetic field, and surface currents on the absorber. By varying the polarization angle and incident angle of the incoming wave, we found that the absorber exhibits polarization insensitivity and wide-angle absorption characteristics. The TE and TM waves maintain more than 90% absorption efficiency up to incident angles of 50° and 60°, respectively. The absorber’s thickness is 1.07 mm, which is 0.0154 times the wavelength corresponding to the lowest resonant frequency (λ0), and the edge length of the subunit’s regular hexagon is 7.5 mm (0.108λ0), making the absorber sub-wavelength in scale while maintaining its compactness. The proposed absorber operates in the C-band and Ku-band, and can be applied in the field of satellite communications, achieving functions such as electromagnetic shielding and stealth.

Solid Intercalation and Exfoliation of Cl-Terminated Multilayered MXenes toward O-Functionalized Single Layers.

Although ion intercalation is becoming a powerful strategy to produce expanded layered materials and atomic layers in aqueous or organic systems, it usually suffers from sluggish kinetics with a long intercalating time of several days. Here, we present a facile approach to produce O-functionalized single-layer MXenes by solid intercalation of Cl-terminated accordion-like MXenes in molten salts and subsequent exfoliation. The process involves the intercalation of metal cations (Li+, Na+ and K+) and anions (CO32-) in molten salts, resulting in substitution with -O surface groups and formation of gases (CO2). Such unique solid intercalation significantly expands multilayered MXenes in 30 min with an enhancement of interlayer spacing from 11.2 to 12.7 Å, facilitating their easy exfoliation to single layers. The resultant O-functionalized MXenes have a highly expanded structure and elevated permittivity, achieving a reflection loss value of -50.5 dB at a thickness of 1.35 mm for electromagnetic wave absorption.

Enhancing security in electromagnetic radiation therapy using fuzzy graph theory

This research investigates the application of fuzzy graph theory to address critical security challenges in electromagnetic radiation therapy systems. Through comprehensive theoretical analysis and experimental validation, we introduce novel approaches leveraging fuzzy cognitive maps and fuzzy graph-based architectures for access control, intrusion detection, secure communication, and risk assessment. The study demonstrates significant improvements over traditional security measures across multiple performance metrics. The fuzzy graph-based access control model achieved a 2.5% false acceptance rate compared to 7.8% in traditional systems, while intrusion detection accuracy improved to 95% with only 3% false positives. Secure communication protocols demonstrated 98% confidentiality and 96% integrity rates, surpassing conventional methods. Risk assessment coverage increased to 92% with reduced false positives. The system maintained linear scaling in processing time from 180 ms at 1000 to 320 ms at 100,000 records, with CPU utilization remaining between 65 and 72%. These findings underscore the immense potential of fuzzy graph theory in strengthening the safety and privacy of electromagnetic radiation therapy systems, providing a foundation for future research and clinical adoption. The study also identifies key directions for future research, including machine learning integration, blockchain implementation, and scalability optimization.

Unmanned Aerial Vehicles for the Monitoring of Telecommunication Towers from the Engineering Approach

In this article, the authors conducted electromagnetic radiation research on telecommunication base stations using Unmanned Aerial Vehicles (UAVs). Until now, UAVs have only been capable of performing visual inspections, without investigating electrical parameters. The authors suggest a method that involves using a spectrum analyzer and an automated flight with a predefined trajectory around the base stations to conduct electromagnetic radiation research, which is used by telecommunication regulatory organizations. Two different types of UAVs were used in this work: a drone and a fixed-wing aircraft, each with distinct characteristics. The authors successfully designed and tested both types of UAVs under real conditions and performed measurements. A specialized algorithm with software was developed for processing measurement results, which accurately presents the data in a graphical format. Experiments were performed, and the results, at distances of 200 m or further from the telecommunication base tower by changing the altitude by 5 m, were collected.

Pipe failure prediction model based on periodic pipe wall thickness measurement using electromagnetic acoustic resonance

This study proposes a numerical model to predict pipe failure based on periodic non-destructive inspections using electromagnetic acoustic resonance (EMAR). A total of 149 artificially corroded samples that simulated flow-assisted corrosion were prepared; 27 of them were plates, and others were from pipes of various dimensions. The samples were measured using EMAR, and the thicknesses of the samples were evaluated based on the fundamental resonance frequency. The results of the evaluations were compared with the actual thicknesses measured by a caliper gauge to quantify the uncertainty in pipe wall thickness evaluation. Numerical evaluations were performed to predict pipe failure probability in the future based on the results of periodic EMAR measurements. Three scenarios of pipe thickness reduction were considered, and each scenario assumed that pipe thickness measurements by EMAR were performed every five years. The actual pipe wall thickness, which is not necessarily the same as the EMAR evaluations, is estimated as a probability density function using the Bayesian approach proposed in an earlier study by the authors. Whereas this study considers only pipe rupture, the results of numerical simulations support the validity of the model especially when the corrosion rate is not constant.

Mechanisms of electromagnetic radiation signal generation and emission induced by concrete cracking

Abstract During the cracking process of concrete, electromagnetic radiation (EMR) signals are emitted as a result of transient stress variations occurring on crack surfaces. By analyzing the characteristics of these EMR signals, researchers can monitor the health status of concrete structures. This study investigates the mechanical and electromagnetic properties of concrete during the cracking process while proposing mechanisms for piezoelectric and frictional charge generation on crack surfaces, based on the theory of electric dipole oscillations. Considering the effects of crack propagation velocity and surface stress, a model for the emission of EMR signals during the propagation of a single crack in concrete has been developed. The model correlates crack distance, applied stress, and the amplitude and frequency of EMR signals. Experimental observations from point load and hydraulic fracturing tests were conducted to investigate the variation patterns of EMR signals within the frequency range of 100 Hz–100 kHz during the evolution of single and multiple cracks in concrete. The experimental results indicate that the amplitude of the EMR signals generated during concrete cracking is directly proportional to the applied stress while inversely proportional to the square of the observation distance. The proposed signal generation and emission mechanism is in strong agreement with the observed experimental phenomena. This theoretical framework provides a deeper understanding of the intrinsic causes of EMR signal generation during concrete cracking, enhancing the interpretability and applicability of EMR-based monitoring techniques for concrete cracking.