Electromagnetic Exposure Research Articles

Effect of skin thickness on electromagnetic dosimetry analysis of a human body model up to 100 GHz

Abstract The accuracy of electromagnetic (EM) exposure assessments depends mainly on the resolution of a voxel human body model. The resolution of the conventional human body model is limited to a few millimeters. In the millimeter wave (mmWave) frequency range, EM waves are absorbed by the superficial tissues in the human body. Therefore, resolution and skin thickness of the human body model are important for accuracy of the EM wave exposure metrics recommended by international human safety guidelines. Realistic thickness modeling of the skin tissue on the human body may provide greater accuracy in the EM exposure assessment, especially at mmWave frequency range. In this paper, effects of the skin thickness on the EM exposure metrics in one-dimensional multi-layered models obtained from different regions of the body model are investigated using the dispersive algorithm based on the finite-difference time-domain method over the frequency range from 1 to 100 GHz. Furthermore, effects of eyelid tissue in a human eye on the EM exposure metrics are studied over the frequency range. The EM exposure metrics such as absorbed power density, heating factor, and power transmission coefficient are calculated up to 100 GHz to evaluate the limits of EM wave exposure.

Electromagnetic compatibility study of trackside antenna array miniaturization in the subway tunnel

Abstract To improve the compatibility of the subway tunnel’s electromagnetic environment and reduce the radiation impact of trackside antennas on subway workers. This paper proposes a miniaturized dual-band trackside antenna array by using metamaterial units. Its operation bandwidth is 2.33 ∼ 2.56 GHz and 3.24 ∼ 3.45 GHz, which could simultaneously satisfy the signal cover demands of the communications-based train control (CBTC) and the civil 5G wireless communication system. The proposed miniaturized antenna array has a maximum gain of 14.4 dBi and a maximum channel capacity of 13.9 bps Hz−1 at a signal-to-noise ratio (SNR) of 20 dB, which can effectively improve the quality of wireless communication systems. The number of trackside antennas with a single operation frequency band is reduced, and the distance between the antennas is enlarged at the same time. Besides that, we analyze the radiation impact on the tunnel electromagnetic environment of the proposed trackside antenna array. In particular, the electromagnetic dose absorbed by the human model of a tunnel worker is quantized. The results show that the electric field strength in the tunnel reduces by 4.11% at least after antenna array miniaturization, and the specific absorption rate (SAR) absorbed by the worker model’s trunk, skull, brain, heart, and liver is reduced by a maximum of 19.02%, 33.16%, 28.27%, 41.75%, and 74.54%, respectively, further lowering the human electromagnetic exposure risk. Therefore, a miniaturized trackside antenna array could reduce the interference from other radiation sources in the tunnel while providing a new idea for electromagnetic protection for subway workers.

Energy Efficiency Optimization of FBMC/OQAM-Based Massive MIMO Systems Subject to Electromagnetic Exposure Constraints

Energy Efficiency Optimization of FBMC/OQAM-Based Massive MIMO Systems Subject to Electromagnetic Exposure Constraints

Effect of ultrahigh frequency ozone therapy on oxidative metabolism in the blood of rats with ischemic skin flaps: A preclinical experimental randomized study

Background. Maintaining and restoring skin microcirculation in surgical flaps, as well as accelerating rehabilitation after skin flap transplantation, in order to mitigate the consequences of burns and injuries, remain a pressing issue. In addition to various timings and techniques for plastic surgery, physiotherapeutic approaches prove to be efficient and include low-intensity electromagnetic radiation in millimeter waves as their prominent techniques. In recent years, experts have paid an increasing attention to the application of low-intensity electromagnetic radiation across different frequency ranges for the enhancement of microcirculation in patients after surgical correction of burn consequences. However, this approach is yet to be further validated. Objective. To investigate the effect of different combinations of ultrahigh frequency electromagnetic radiation with ozone therapy on the oxidative metabolism of blood in rats using a model of ischemic skin flaps. Methods. A preclinical experimental randomized study was conducted on 100 adult male Wistar rats weighing between 200 and 250 grams. Five equal-sized groups of animals were formed in the study: Group 1: intact (no interventions), and Groups 2, 3, 4, and 5: after surgical intervention (modeling of ischemic skin flaps). Animals in Group 2 (control group) received no therapeutic procedures. Rats in Groups 3 and 5 underwent a 10-minute course of electromagnetic radiation exposure with a dose of 0.06 mJ for seven days. Animals in Group 3 were exposed to electromagnetic radiation of ultrahigh frequency with a range of 53–78 GHz. Animals in Group 4 received injections of ozonized saline solution (with a saturating ozone concentration in the ozonized oxygen mixture of 3000 µg/L) daily for 7 days, administered intraperitoneally at a volume of 1 mL. Group 5 underwent a combined treatment: daily exposure to ultrahigh frequency electromagnetic radiation along with intraperitoneal ozone therapy (the application modalities of these treatments were similar to those used in Groups 3 and 4, respectively). The intensity of lipid peroxidation, peroxide resistance in erythrocytes, and overall antioxidant system activity were assessed in order to investigate the balance of pro- and antioxidant systems in plasma and erythrocytes. Additionally, the study involved determination of the level of malondialdehyde content and evaluation of the activity of superoxide dismutase and catalase in erythrocytes. The obtained date were analyzed, using MS Office 2013 (Microsoft Corporation, USA) and Statistica 10 (StatSoft, USA). Results. The conducted analysis revealed an antioxidant effect from ultrahigh frequency electromagnetic radiation, with this effect being enhanced by ozone therapy. In addition, the study detected the inhibition of free radical oxidation under the ultrahigh frequency electromagnetic radiation and ozone therapy. Conclusion. Thus, the positive effects of the studied therapeutic factors manifest at the systemic level, as evidenced by the optimization of biochemical parameters and indicators of oxidative metabolism in the plasma of animal blood. It has been established that ultrahigh frequency electromagnetic radiation, administered in a noise mode, exerts a regulatory effect on pro- and antioxidant systems in the body, as demonstrated in a model of transplanted skin flap. This intervention leads to a reduction in the severity of oxidative stress and an enhancement of antioxidant reserves in the blood. The observed effect is further amplified with the additional application of ozone therapy.

The influence of eyelashes on electric field distribution and absorbed power density in the cornea under millimeter-wave exposure.

As millimeter wave (MMW) technology, particularly in fifth-generation (5G) devices, gains prominence, there is a crucial need for comprehensive electromagnetic (EM) models of ocular tissues to understand and characterize EM exposure conditions accurately. This study employs numerical modeling to investigate the interaction between MMW and the cornea, aiming to characterize EM field distributions and absorption within an anatomically accurate eye model while considering the influence of eyelashes. Using the finite-difference time-domain (FDTD) method, we conduct simulations of EM radiation interactions from 20.0 to 100.0 GHz with a human eye model. Moreover, we analyze the temperature distribution increase within the eye model using a thermal sensor in XFdtd, employing a scheme based on the finite difference (FD) method. Our findings reveal a nonuniform distribution of the EM field, particularly intensified in corneal regions adjacent to eyelashes and eyelids. Despite similar EM field patterns, the presence or absence of eyelashes has minimal impact on temperature differences. However, the study highlights increased radiation absorption by the eyelid's epidermis at 100.0 GHz, reducing the rise in the cornea's temperature.

Effects of 4.9 GHz Radiofrequency Field Exposure on Brain Metabolomic and Proteomic Characterization in Mice.

Electromagnetic exposure has become increasingly widespread, and its biological effects have received extensive attention. The purpose of this study was to explore changes in the metabolism profile of the brain and serum and to identify differentially expressed proteins in the brain after exposure to the 4.9 GHz radiofrequency (RF) field. C57BL/6 mice were randomly divided into a Sham group and an RF group, which were sham-exposed and continuously exposed to a 4.9 RF field for 35 d, 1 h/d, at an average power density (PD) of 50 W/m2. After exposure, untargeted metabolomics and Tandem Mass Tags (TMT) quantitative proteomics were performed. We found 104 and 153 up- and down-regulated differentially expressed metabolites (DEMs) in the RF_Brain group and RF_Serum group, and the DEMs were significantly enriched in glycerophospholipid metabolism. Moreover, 10 up-regulated and 51 down-regulated differentially expressed proteins (DEPs) were discovered in the RF group. Functional correlation analysis showed that most DEMs and DEPs showed a significant correlation. These results suggested that 4.9 GHz exposure induced disturbance of metabolism in the brain and serum, and caused deregulation of proteins in the brain.

Interaction between Electromagnetic (EM) wave and human head: Normal adult and elderly heads

In recent years, there has been an increasing public concern about the health implications of electromagnetic (EM) wave exposure with the use of mobile telephones. In this paper, we have evaluated the EM absorption in the human head at GSM 900 MHz (Global System for Mobile telecommunications) and DCS 1800 MHz (Digital Cellular System) radiation. Two models for human head were considered. The first model was normal adult head whereas the second model was normal elderly head. First, a stratified structure of the human head is modeled. Next, a two-dimensional (2-D) cylindrical head model based on finite-difference time-domain (FDTD) method is investigated. Our previous described 2-D FDTD code based on LabVIEW has been utilized. Much attention has been paid to the induced specific absorption rate (SAR) in elderly human head.

Microwave Frequency Analysis of Dielectric Properties in Biological Tissues: Insights into Dielectric Constant, Conductivity, and Resistivity at 9.4 GHz

This study investigates the dielectric properties of various biological tissues at microwave frequencies, specifically focusing on their dielectric constant, conductivity, resistivity, and loss tangent. Using methods such as Von Hippel’s and Yadav Gandhi’s techniques, the dielectric characteristics of heart, liver, brain, and muscle of chicken tissues were analysed at 9.4 GHz. It is found that tissues with higher water content exhibit greater dielectric constants and conductivities, while those with higher solid content, like liver, display higher resistivity. It has also been observed that tissues with lower dielectric constants and conductivities are those with greater absorption indices, which are typically associated with increased energy dissipation as heat. An increasing amount of energy dissipation may result from tissues with higher absorption rates being less effective at transferring microwave energy, as suggested by this inverse connection, which also emphasizes the complexity of electromagnetic wave interaction within tissues. This work provides critical insights into the interaction of electromagnetic waves with biological tissues, which is essential for applications in medical diagnostics, therapeutic technologies, and electromagnetic exposure safety standards.

Vulnerability module in the multi-level ontology of risk assessment of Wireless Sensor Networks

This work presents the development of a vulnerability module within a multi-level ontology for risk assessment in wireless sensor networks (WSNs) used in industrial environments. WSNs consist of multiple sensor nodes with microcontrollers, sensors, communication devices, and power sources, playing a key role in monitoring, diagnostics, and managing industrial processes. Their main advantages include reduced costs due to the lack of cabling and ease of scaling by adding new nodes. However, WSNs face significant challenges, including limited power supply, vulnerability to electromagnetic interference, low bandwidth, and exposure to cyber-attacks. These issues make them less suitable for real-time systems where fast and reliable data transmission is critical. The vulnerability module developed in this study addresses these challenges by identifying weaknesses, analyzing potential threats, and assessing risks using logical rules. These rules assess various network components such as devices, communication protocols, and external factors like physical access and radio interference. The module continuously monitors the network, detects new vulnerabilities, and provides real-time feedback to the risk assessment module, suggesting measures to mitigate risks. This enhances the security and reliability of WSNs in industrial applications. In conclusion, the vulnerability module within the multi-level ontology provides a structured approach to identifying and mitigating risks in WSNs. Despite the inherent vulnerabilities of WSNs, advancements in security protocols and energy efficiency make them increasingly viable for industrial automation and optimization.

Rotation insensitive implantable wireless power transfer system for medical devices using metamaterial-polarization converter

This article introduces an innovative approach for creating a circular polarization (CP) antenna-based rotation-insensitive implantable wireless power transfer (WPT) system for medical devices. The system is constructed to work in the industrial, scientific, and medical (ISM) frequency band of 902–928 MHz. Initially, a flexible, wide-band, and bio-compatible open-ended CP slot antenna is designed within a single-layer human skin tissue model to serve as the receiving (Rx) element. To form the implantable WPT link, a circular patch antenna is also constructed in the free-space to use as a transmitting (Tx) source. Further, a new metamaterial-polarization converter (MTM-PC) structure is developed and incorporated into the proposed system to enhance the power transfer efficiency (PTE). Furthermore, the rotational phenomenon of the Rx implant has been studied to show how the rotation affects the system’s performance. Moreover, a numerical analysis of the specific absorption rate (SAR) is conducted to confirm compliance with safety regulations and prioritize human safety from electromagnetic exposure. Finally, to validate the introduced concept, prototypes of the different elements of the proposed WPT system were fabricated and tested using skin-mimicking gel and porcine tissue. The measured results confirm the feasibility of the introduced approach, exhibiting improved efficiency due to use of the MTM-PC. The amplitude of the transmission coefficient (|S21|\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|S_{21}|$$\\end{document}) has improved by 6.94 dB in the simulation, whereas the enhancement of 7.04 dB and 6.76 dB is obtained from the experimental study due to the integration of MTM-PC. As a result, the PTE of the proposed MTM-PC integrated implantable WPT system is increased significantly compared to the system without MTM-PC.

Safety evaluation of electromagnetic exposure for compact wireless charging stations of electric vehicles

ABSTRACT The spatial electromagnetic field of electric vehicle (EV) wireless charging stations may experience a superposition effect, which will increase the electromagnetic radiation. To assess the safety of electromagnetic exposure from wireless charging stations, this study employs a finite element simulation software to construct an electromagnetic environment model for a compact wireless charging station. The model is utilized to compute the superposition effect of spatial electromagnetic fields resulting from the simultaneous charging of multiple wireless chargers. Furthermore, the model assesses the levels of electromagnetic exposure on human models at eight observation points situated within the charging station. Results indicate that the volume average values of spatial magnetic induction strength ( B ) and electric field strength ( E ) are higher when multiple EVs are charged simultaneously than when a single EV is charged, and the electromagnetic radiation received by a human standing between two vehicles is greater than that near one vehicle. At the 22 kW charging power level, the maximum values of B , E and current density at the eight observation points of the charging station are all below the International Commission on Non-Ionizing Radiation Protection limit, demonstrating that the human body is safe in compact wireless charging stations at this power level.

Computational analysis of electromagnetic field exposure in passengers near high- current contact wire environments.

The electromagnetic environment of a railway station is composed of electrical, magnetic, and electromagnetic fields, which are generated by various sources such as traction current, voltage, pantograph-catenary arc, locomotive braking, wheel-rail rolling arc, and communication systems. However, there is public growing concern among the public about the potential negative human health effects of this electromagnetic environment. To analyze the distribution of electromagnetic fields in human tissues, electromagnetic simulation software is used to create a model that includes six track contact wires and four waiting passengers on three platforms. This model is used to analyze the magnetic field environment created by high currents in the contact wires of a multi-track high-speed railway station. By varying the loads on different contact wires, the distribution of electric field and magnetic flux density within human tissues of waiting passengers on different platforms is studied using this model. When the track is unoccupied, the calculation results show that the maximum values of the electric field and magnetic flux density of the passenger's human body tissue at the blind way on the platform and 1m of the blind way are 17.6mVm-1 and 52.7 μT, respectively. These values increase by 9.28mVm-1 and 16.4 μT compared to when the track is occupied. When more contact wires are loaded with currents, the electric field mode and magnetic flux density mode of human tissues increase at the same position on the platform. Specifically, when the contact wires of six tracks are loaded with current at the same time, the maximum values of the electric field mode and magnetic flux density mode of the waiting passengers' human tissues at the blind way on different platforms are 29.6mVm-1 and 88.1 μT, respectively. These maximum values are lower than the public electromagnetic exposure limits that are designated by the International Commission on Non-Ionizing Radiation Protection guidelines. The research results demonstrate that the magnetic field environment generated by the current in the contact wires of a railway station with six tracks does not pose a health risk to human tissues of passengers waiting at the blind way and 1m of the blind way on the platform. These findings can provide valuable data reference for the formulation of relevant standards for the design of electrified rail transit, as well as the suppression of electromagnetic interference and protection of human bioelectromagnetism.

Synergistic Cellular Responses Conferred by Concurrent Optical and Magnetic Stimulation Are Attenuated by Simultaneous Exposure to Streptomycin: An Antibiotic Dilemma.

Concurrent optical and magnetic stimulation (COMS) combines extremely low-frequency electromagnetic and light exposure for enhanced wound healing. We investigated the potential mechanistic synergism between the magnetic and light components of COMS by comparing their individual and combined cellular responses. Lone magnetic field exposure produced greater enhancements in cell proliferation than light alone, yet the combined effects of magnetic fields and light were supra-additive of the individual responses. Reactive oxygen species were incrementally reduced by exposure to light, magnetics fields, and their combination, wherein statistical significance was only achieved by the combined COMS modality. By contrast, ATP production was most greatly enhanced by magnetic exposure in combination with light, indicating that mitochondrial respiratory efficiency was improved by the combination of magnetic fields plus light. Protein expression pertaining to cell proliferation was preferentially enhanced by the COMS modality, as were the protein levels of the TRPC1 cation channel that had been previously implicated as part of a calcium-mitochondrial signaling axis invoked by electromagnetic exposure and necessary for proliferation. These results indicate that light facilitates functional synergism with magnetic fields that ultimately impinge on mitochondria-dependent developmental responses. Aminoglycoside antibiotics (AGAs) have been previously shown to inhibit TRPC1-mediated magnetotransduction, whereas their influence over photomodulation has not been explored. Streptomycin applied during exposure to light, magnetic fields, or COMS reduced their respective proliferation enhancements, whereas streptomycin added after the exposure did not. Magnetic field exposure and the COMS modality were capable of partially overcoming the antagonism of proliferation produced by streptomycin treatment, whereas light alone was not. The antagonism of photon-electromagnetic effects by streptomycin implicates TRPC1-mediated calcium entry in both magnetotransduction and photomodulation. Avoiding the prophylactic use of AGAs during COMS therapy will be crucial for maintaining clinical efficacy and is a common concern in most other electromagnetic regenerative paradigms.

Proximity Effects of Electromagnetic Field Radiation from Cellular Wireless System on Living Things and Their Mitigation Techniques

Research on electromagnetic field radiation exposure from cellular wireless systems is expected to become more important, allowing researchers to provide solutions for the effects of this radiation on human living beings. During the research, experiment animals were unprotected to RF radiations for 8 hours every day for 30 days. The exposure duration involved the placement of test animals in Plexiglass boxes. An RF transmitter was placed on the cage's roof from within. The transmitter emitted EMF radiations that were noted in rats. An elevated plus maze and open field test was utilized to determine behavioral parameters. On the 8th, 15th and 30th day of exposure, behavioral tests were administered. According to our findings, EMF radiation toxicity is closely linked with the exposure to this form of radiation. An increase in the toxicity level was observed as exposure time passed. Furthermore, this research demonstrated that EMF radiation exposure resulted in neuronal injury. The RF transmitter was subjected to tests with shielding materials, including woven and non-woven fabrics, which serve as technical textiles for electromagnetic radiation protection.

Electromagnetic Field Monitoring by Fixed Stations in Romania: Data Processing Methods and Outcomes

Abstract Electromagnetic field (EMF) monitoring activities provide transparent information to the public interested in the safety levels of human exposure when using various radiofrequency (RF) emitting technologies. In the present work, we investigate different methods of data processing that enable relevant knowledge extraction from the databases gathered by the Romanian EMF-fixed monitoring network. Four categories of methods are proposed and illustrated by investigating the situation of electromagnetic exposure at three locations in Bucharest, during 25 months. The conducted application methods enables field level distributions and trends, time-variability on the short- and long-term basis, cumulative influence comparison and sensing of the significant changes in the environment.

INFLUENCE OF ELECTROMAGNETIC TREATMENT ON HYDRAULIC CHARACTERISTICS OF HOT PIPELINES DURING NEWTONIAN AND NON-NEWTONIAN PETROLEUM SYSTEMS TRANSPORTATION

This work examines the influence of radio-frequency (RF) electromagnetic (EM) influence on the hydraulic characteristics of hot pipelines for the transport of petroleum Newtonian and non-Newtonian systems.Newtonian and non-Newtonian petroleum and their rheological properties before and after RF EM exposure, as well as the hydraulic characteristics of hot petroleum pipelines for pumping selected petroleum, were selected as objects of study.As a result: a methodology for petroleum processing has been developed that corresponds to industrial practice in the operation of petroleum pipelines; empirical dependences of petroleum viscosity on temperature were obtained in the form of piecewise exponential functions. The influence of RF EM exposure on the thixotropic properties of petroleum and the values of ultimate shear stresses was assessed. A decrease or complete disappearance of hysteresis loops after RF EM exposure to petroleum and a decrease in the maximum shear stress for non-Newtonian petroleum were revealed.By using the software developed by the authors, «Hydraulic calculation of isothermal and non-isothermal petroleum pipelines (GRINT)», the processes of pipeline transport of petroleum treated with EM fields were modeled, taking into account the obtained empirical dependencies. An assessment of the influence of RF EM exposure on the hydraulic characteristics of «hot» pipelines was carried out. It has been established that after RF EM exposure to petroleum, the zone of stable operation of a «hot» petroleum pipeline increases and the required pressure for pumping the same volume of petroleum decreases.

Safety Assessment of Electromagnetic Environmental Exposure for GPS Antenna of Electric Vehicle

The present GPS (global positioning system) is widely used in electric vehicle navigation; it is usually installed in the middle-to-rear position on the car’s roof, near the rear windshield. Since the GPS antenna operating frequency is 1.575 GHz, the health risk of the passengers in the car in this high-frequency electromagnetic exposure is a matter of concern. In this paper, we construct models for a GPS antenna, an electric vehicle, and a human body. Through the multiphysics field coupling calculation in COMSOL Multiphysics, a finite element simulation software, in both frequency domain and transient analysis, we obtain the electric field strength distribution, specific absorption rate, and temperature distribution of the human body at three positions inside the electric vehicle after being exposed to the GPS antenna radiation for 30 minutes. The peak human-induced electric field is 18.4 V/m, and the peak specific absorption rate is 0.193 W/kg. The 30 minute average maximum human-induced electric field is 1.6906 V/m, which is 3.1% of the ICNIRP limit, the 30 minute average whole-body SAR is 0.0036 W/kg, which is 4.5% of the ICNIRP limit, and the 30 minute average human core temperature rise is 0.06°C, which is 6% of the ICNIRP limit. In addition, we simulate the impact of three different vehicle shell materials on the level of electromagnetic exposure to the human body, which can provide reference for electromagnetic shielding design in automobiles. The results indicate that the induced electric field strength, specific absorption rate (SAR), and temperature rise in various parts of the human body did not exceed the standard limits in the latest version of ICNIRP. This suggests that the electromagnetic exposure from the GPS antenna in a typical automotive environment does not pose a threat to human health.

Research on the influence of power frequency magnetic field of pantograph on pacemaker wearers' health in high-speed EMU.

When the popular means of transportation-high-speed trains meet the increasing rate of pacemaker implantation year by year, the research on the magnetic field environment on the health of pacemaker wearers in the carriage becomes an urgent problem. In this work, models of an electric multiple unit carriage with a pantograph as well as passengers with pacemakers were built by using COMSOL Multiphysics software. The B, Ein and Jin of human heart and other tissues, and the induced voltage (Vin) at the pacemaker electrode were calculated under the pantograph operating condition, so as to assess the effect of its magnetic field on the health of pacemaker wearers. The results showed that Bmax in the carriage without passengers is 121.246 μT, occurs near the window. In the carriage, the Bmax, Ein max and Jin max of heart and body, Vin at the pacemaker electrode of the passenger next to the window are greater than that in the middle of the carriage. The Bmax, Ein max and Jin max of passengers' heart are 11.301μT, 1.613mV/m and 139.030μA/m2, respectively. The Bmax, Ein max and Jin max of passengers' body are 12.597μT, 0.788mV/m and 75.299μA/m2, respectively. The maximum value of Vin at the tip of the pacemaker electrode of the passengers' is 0.048mV. The Bmax, Ein max in all tissues of passengers are much smaller than the basic limits of electromagnetic exposure to the public set by the International Commission on Non-Ionizing Radiation. Vin at the electrode tip of passengers' pacemakers are less than the perception sensitivity set by the International Organization for Standardization. This work illustrated that the magnetic field generated by the pantograph is within the recognized accepted limits for passengers with pacemakers, but we still recommended that passengers wearing pacemakers should stay as far away from windows as possible.

Electromagnetic exposure analysis of the subway passenger under the civil communication system radiation.

In order to assess the electromagnetic exposure safety of passengers under the civil communication system of the subway, the radio-frequency (RF) electromagnetic environment of subway carriage is established by using COMSOL Multiphysics software, it includes a 1-1/4 " leaky coaxial cable (LCX1) and a 1-5/8" leaky coaxial cable (LCX2), which are designed to be the exposure sources, and twelve passengers at different position. The electromagnetic environment model has been verified through field measurement. The exposure dose distribution of twelve passengers is compared and analyzed, when LCX1 and LCX2 works respectively. The simulated results show that, to compare with LCX2, the electromagnetic dose absorbed by the passengers is reduced by 9.19% and 22.50% at 2100 MHz and 2600 MHz respectively. The specific absorption rate (SAR) of passengers obtains the maximum value of 1.91×10-4 W/Kg and the temperature rise to 0.214 K when the LCX1 works at 3400 MHz. By comparing with the public exposure limitation of the International Commission of Non-Ionizing Radiation Protection (ICNIRP), it demonstrates the electromagnetic exposure safety of the passengers under the civil communication system. More importantly, the proposed LCX1 not only could add the 5G signal cover but also lower the SAR absorbed by the passengers, which indicates that the public electromagnetic exposure dose could be reduced by adjusting the radiation performances of exposure source, which provide a new way for electromagnetic protecting.

Electromagnetic Environment Assessment and Safety Research of Electrified High-Speed Railway Carriages

With the advent of modern, high-speed electrified rail systems, there has been increasing concern about electromagnetic safety in rail carriages. The aim of this study was to assess the electromagnetic safety of passengers on trains by utilizing advanced 3D electromagnetic simulation software. A comprehensive model of the electromagnetic environment experienced by passengers on a CR400AF train, specifically under the influence of catenary radiation, was constructed. We analyzed the magnetic field strength, electric field strength, and current density in the brains of 20 passengers in various positions in the train. The findings revealed that among the 20 passengers analyzed, the maximum and minimum magnetic induction intensity recorded in the brain were 8.41 and 0.01 μT, respectively. The maximum and minimum induced electric field intensities were 1110 and 10 μV/m, respectively. Lastly, the maximum and minimum induced current densities were 1200 and 10 μA/m2, respectively. The results show that when people ride on the CR400AF train, the magnetic induction intensity, induced electric field strength, and induced current density in the brain are below the recommended basic limits of exposure to power frequency electromagnetic fields in the guidelines of the International Committee on Non-Ionizing Radiation Protection. The power frequency magnetic field generated by the catenary can be effectively shielded by the aluminum alloy car body. The final result of this study indicates that the electromagnetic exposure from the contact wire at the level 25 kV does not pose a threat to the health of passengers on the CR400AF train.