Wireless Communication Devices Research Articles

Reconfigurable Metamaterial Antenna based an Electromagnetic Ground Plane Defects for Modern Wireless Communication Devices

In this paper, a design of a microstrip antenna based on metamaterial (MTM) and electromagnetic band gap (EBG) arrays. The patch is structured from 5×3 MTM array to enhance the antenna bandwidth gain product. The individual unit cell is structured as a split ring (SRR) with a T-resonator. The ground plane is defected with an EBG to suppress the surface waves diffraction from the substrate edges. The antenna is printed on a Roger substrate with permittivity of 10.2 and 1 mm thickness. It is found that the proposed antenna provides a frequency resonance around 2.45 GHz and 3.5 GHz with another band between 4.6 GHz to 5.6 GHz which are very suitable for Wi-Fi and 5G networks. Nevertheless, the antenna gain is found to vary from 3.5 dBi to less than 6 dBi. The antenna size is reduced enough to λ/5 of the guided wavelength to fit an area of 12 mm×20 mm. The proposed antenna performance is controlled with two PIN diodes for reconfiguration process. The antenna frequency resonance bands are found to be well controlled by stopping the current motion at the particular band. The antenna is fabricated and tested experimentally. Finally, the simulated results are compared to those obtained from measurements to provide an excellent agreement to each other with error of less than 3%.

Radio-Frequency Conductivity Evaluation Method Based on Surface/Interface Scattering of Metallic Coatings

Developing non-destructive evaluation methods for the radio frequency (RF) conductivity of conductive coatings can accelerate the performance evaluation and development of wireless communication devices. By using a split-resonator cavity to compare 800 nm copper/graphite and 1000 nm copper/graphite, we found that the RF conductivity increased by 45.5% and 82.7%, respectively, from 15 GHz to 40 GHz (pure copper was −7.2%), indicating that the bulk materials analysis method is not suitable for coating materials. Combined with electromagnetic wave theory, we believe that the critical factor lies in the additional losses of the electromagnetic waves at the copper/graphite interface and substrate. Based on the skin depth theory, the concept of triple skin depth is proposed to calculate the power loss of copper/graphite at different frequencies, considering rough Peff (including the power loss of the rough surface, copper coatings, copper/graphite interface, and graphite) compared with smooth pure copper Pc. Combined with the relationship between RF conductivity and electromagnetic wave power loss, the conductivity of copper coatings σCu at different frequencies is obtained by analyzing the measured σeff. Compared with the roughness model, the calculation error decreased from 30% to below 7%. Our study provides a theoretical basis for the regulation of the RF conductivity of metal coatings at different frequencies.

Microstructural and dielectric properties of civil construction ceramic waste sintered at various temperatures

This study investigates the dielectric properties of ceramic waste derived from roof tiles and bricks commonly used in civil construction. The materials were analyzed by grinding them into a fine powder, followed by producing of cylindrical samples through uniaxial pressing on a steel matrix. The samples were sintered at temperatures of 1000 °C, 1050 °C, and 1100 °C to analyze the effect of temperature on the electrical characteristics of the ceramics. XRD and SEM analyses were performed to evaluate microstructural parameters and coalescence behavior. The dielectric characterization aimed to obtain the real relative electrical permittivity with average values of 2.85, 3.56, and 3.65, correlated with apparent porosity levels of 30.74 %, 20.54 %, and 9.11 %, and the loss tangent of 7.5 × 10−5, 3.9 × 10−5, and 12 × 10−5, respectively. The loss tangent values are lower than those obtained in commercial dielectrics from 1 to 6 GHz frequency range. The dielectric characteristics of samples manufactured from ceramic waste from bricks and tiles can serve as sustainable alternatives to produce dielectric resonator antennas (DRA), applicable to fifth-generation wireless communication devices in the sub-6GHz band.

Traffic Management System Using IOT

Abstract: Traffic congestion is a major threat to transportation sector in every urban city around the world. This causes many adverse effects like, heavy fuel consumption, increased waiting time, pollution, etc. and causes major challenge to the movement of emergency vehicles. The reaction time required by the emergency responders plays a vital role to handle the situation. The greatest challenge they face is congestion of traffic flow. This paper presents an approach to schedule emergency vehicles in traffic. The approach combines the controlling of traffic congestion by IR sensors and detection of emergency vehicle using by RFID scanner method. The IR sensors is responsible for vehicle counting and RFID for the emergency vehicle. An IR sensors continuously count the passing vehicles & records the delay time between two vehicles. Flow of vehicles is normal means there is smooth traffic flow, or if in case, the passing time between two vehicles is decreased that means traffic congestion is happen ahead. In this situation traffic light turns to green, so that the emergency vehicle will reach its destination as fast as possible. The aim of this article is to identify and monitor the congestion system in order to provide efficient facilities. This journal also sets out a method that uses 433 MHZ RF Transmitter and receiver Wireless communication device technique and Internet of Things (IoT) to transmit the treatment request from the ambulance to the nearby hospitals and at the same time the LCD is installed on the road junction which displays the nearby hospital name and contact number for the ambulance, this smart traffic system which in turn changes the traffic signal cycle. This system can be implemented throughout the city thereby to reducing the delay.

The Impact of Electromagnetic Fields on Human Health: A Review

The electromagnetic field (EMF) is a physical concept consisting of electric and magnetic fields produced by the motion of charged particles and plays a ubiquitous role in modern society. EMFs are present in various forms, ranging from extremely low frequency (ELF) fields produced by power lines to radiofrequency (RF) fields emitted by wireless communication devices. While EMFs are essential for technologies like electricity generation, telecommunications, and medical imaging, concerns have been raised regarding their potential impact on human health. The literature has explored the relationships between EMF exposure and health outcomes, including cancer, reproductive health, and neurological disorders. Despite ongoing debate and inconclusive evidence, efforts are underway to mitigate exposure and establish regulatory guidelines. The effects of EMF on human health is a complex and multifaceted issue and research points to potential effects on various aspects of health, including neurological, reproductive and developmental effects. Although significant associations have not been found in some studies, growing evidence suggests that continuity in research is important in assessing and mitigating potential health risks associated with EMA exposure.

Cryogenic and ultrasonic-assisted micro-drilling of printed circuit boards using high-frequency-amplitude spindle

Printed circuit boards (PCBs) are key components in computers, 5G, 6G, and other wireless communication devices. On the other hand, the manufacture of micro-holes in PCBs faces severe challenges. Conventional micro-drilling methods often encounter challenges such as poor surface quality and limited tool life. To overcome these issues, a novel micro-drilling method called cryogenic and ultrasonic-assisted micro-drilling (CUAMD) has been developed. This study compared four drilling methods to investigate the benefits of cryogenic and ultrasonic-assisted drilling in hybrid machining processes: conventional micro-drilling (CMD), cryogenic-assisted micro-drilling (CAMD), ultrasonic-assisted micro-drilling (UAMD), and cryogenic and ultrasonic-assisted micro-drilling (CUAMD). The experimental results unequivocally indicate that the utilization of cryogenic-assisted drilling leads to a significant reduction in cutting heat during the machining process. This not only contributes to an improvement in machining accuracy but also exerts a positive influence on tool life and surface morphology. Ultrasonic-assisted drilling separates chips into smaller volumes through high-frequency-vibration, effectively reducing the cutting forces. The high frequency of 38.25 kHz and high amplitude vibration of 5.16 μm of the ultrasonic spindle induced vibrations on the drill bit. Liquid nitrogen with a pressure and temperature of 28 kPa and − 196 °C, respectively, was used in the cryogenic-assisted method. The superior machining performance of the CUAMD approach was evaluated by comparing it to various methods, including cutting forces, tool flank wear, entrance/exit hole morphology, and chip formation. The CUAMD method avoids chip entanglement, suppresses burrs, and reduces the maximum cutting force, maximum torque, and exit hole damage factor Fd by 47.7 %, 56.1 %, and 42.5 %, respectively, compared with CMD.

An ultra-compact mechanical antenna based on PTFE highly charged electret for extremely low frequency communications

—Extremely-Low Frequencies (ELF, 30∼300Hz) transmitting antennas in wireless communications are often limited by antenna size and complex impedance matching networks. In this paper, we propose an ultra-small Artificial Electret Type Mechanical Antenna (AETMA), which is composed of a single charge electret and a driving structure, with high radiation efficiency and small size. In order to improve the electric dipole moment of the mechanical antenna, we employ a pin-plate corona polarization technique and a unidirectional stretching treatment to obtain a porous thin-film electret that can stably store a large amount of charge. Its surface charge density can reach 5.355 mC/m2 and we analyze its surface potential stability. To assess the radiation capability of AETMA, the radiation field models of three kinds of mechanical antennas are established and verified by simulation. Additionally, we simulate and compare the planar electret and curved electret configurations to determine the optimal form of AETMA. The radiation intensity of the planar electret is found to be superior under the same moment of inertia. Finally, a 1m-scale artificial electret antenna is designed based on the optimal model. Comparative analysis with existing rotary mechanical antenna schemes confirms the great potential of the proposed AETMA for portable, miniaturized and high-performance wireless communication devices.

A Fairness-Enhanced Federated Learning Scheduling Mechanism for UAV-Assisted Emergency Communication.

As the frequency of natural disasters increases, the study of emergency communication becomes increasingly important. The use of federated learning (FL) in this scenario can facilitate communication collaboration between devices while protecting privacy, greatly improving system performance. Considering the complex geographic environment, the flexible mobility and large communication radius of unmanned aerial vehicles (UAVs) make them ideal auxiliary devices for wireless communication. Using the UAV as a mobile base station can better provide stable communication signals. However, the number of ground-based IoT terminals is large and closely distributed, so if all of them transmit data to the UAV, the UAV will not be able to take on all of the computation and communication tasks because of its limited energy. In addition, there is competition for spectrum resources among many terrestrial devices, and all devices transmitting data will bring about an extreme shortage of resources, which will lead to the degradation of model performance. This will bring indelible damage to the rescue of the disaster area and greatly threaten the life safety of the vulnerable and injured. Therefore, we use user scheduling to select some terrestrial devices to participate in the FL process. In order to avoid the resource waste generated by the terrestrial device resource prediction, we use the multi-armed bandit (MAB) algorithm for equipment evaluation. Considering the fairness issue of selection, we try to replace the single criterion with multiple criteria, using model freshness and energy consumption weighting as reward functions. The state of the art of our approach is demonstrated by simulations on the datasets.

Efficient broadband fractal antenna for WiMAX and WLAN

This article presents a new design of a compact fractal antenna that operates across various wireless communication applications with wideband functionality. With a peak gain of 6.8 dB and a radiation efficiency ranging from 91% to 94%, the designed antenna operates in the frequency range of 3.2–7.5 GHz. The antenna consists of a rectangular radiator with integrated rectangular slots on one side of an FR4 substrate, while a partial ground plane is etched on the other side. The fabricated prototype was tested and measured. The results present a good agreement with the simulated results. The results presented by this antenna demonstrate high competitiveness for wireless communication applications such as Wi-Fi and WLAN and presents a promising solution to meet the increasing demand for compact and high-performance wireless communication devices. Additionally, the antenna has a small size of only 34 × 30 × 1.6 mm3, making it suitable for applications where space is limited. Overall, this paper provides an innovative and efficient design that offers excellent performance and is suitable for various wireless communication applications.

Fabrication of an Optically Transparent Planar Inverted-F Antenna Using PEDOT-Based Silver Nanowire Clear Ink with Aerosol-Jet Printing Method towards Effective Antennas

We report the design, fabrication, and experimental characterization of an optically transparent printed planar inverted-F antenna (PIFA) operating at 2.45 GHz using the aerosol jet (AJ) printing method. The proposed antenna was fabricated using a clear conductive ink on glass and Delrin. The antenna exhibits a wide fractional bandwidth (FBW) of 20% centered at 2.45 GHz, with a peak realized gain of −3.6 dBi and transparency of ~80%. The proposed fabrication method provides a cost-effective and scalable solution for manufacturing transparent antennas with potential applications in wireless communication, sensing, and wearable devices operating at mmWave frequencies higher than 30 GHz.

Novel Meta-Fractal Wearable Sensors and Antennas for Medical, Communication, 5G, and IoT Applications

Future communication, 5G, medical, and IoT systems need compact, green, efficient wideband sensors, and antennas. Novel linear and dual-polarized antennas for 5G, 6G, medical devices, Internet of Things (IoT) systems, and healthcare monitoring sensors are presented in this paper. One of the major goals in the evaluation of medical, 5G, and smart wireless communication devices is the development of efficient, compact, low-cost antennas and sensors. Moreover, passive and active sensors may be self-powered by connecting an energy-harvesting unit to the antenna to collect electromagnetic radiation and charge the wearable sensor battery. Wearable sensors and antennas can be employed in smart grid applications that provide communication between neighbors, localized management, bidirectional power transfer, and effective demand response. A low-cost wearable antenna may be developed by etching the printed feed and matching the network on the same substrate in the printed antenna. Active modules may be placed on the same dielectric board. The antenna design parameters and a comparison between the computation and measured electrical performance of the antennas are presented in this paper. The electrical characteristics of the new compact antennas in the vicinity of the patient’s body were simulated by using electromagnetic simulation techniques. Fractal and metamaterial efficient antennas and sensors were evaluated to maximize the electrical characteristics of smart communication and medical devices. The dual- and circularly polarized antennas developed in this paper are crucial to the evaluation of wideband and multiband compact 5G, 6G, and IoT advanced systems. The new efficient sensors and antennas maximize the system’s dynamic range and electrical characteristics. The new efficient wearable antennas and sensors are compact, wideband, and low-cost. The operating resonant frequency of the metamaterial antennas with circular split-ring resonators (CSRRs) may be 5% to 9% lower than the resonant frequency of the sensor without CSRRs. The directivity and gain of the metamaterial fractal antennas with CSRRs may be up to 3 dB higher than the antennas without CSRRs. The directivity and gain of the metamaterial fractal passive sensors with CSRRs may be up to 8.5 dBi. This study presents new wideband active meta-fractal antennas and sensors. The bandwidth of the new sensors is around 9% to 20%. At 2.83 GHz, the receiving active sensor gain is 13.5 dB and drops to 8 dB at 3.2 GHz. The receiving module noise figure with TAV541 LNA is around 1dB.

Microwave Power Transmission Using a Signal-to-Leakage-and-Noise Ratio to Protect Wireless Communication Devices

Microwave Power Transmission Using a Signal-to-Leakage-and-Noise Ratio to Protect Wireless Communication Devices

Flexible and stretchable polyester@reduced graphene oxide composite fabric for tunable electromagnetic absorption

The widespread application of 5 G wireless communication and flexible electronic devices has put forward new demands for electromagnetic (EM) absorbing materials. In this work, a flexible composite fabric was successfully prepared by using polyester (PET) knitted fabric as an elastic scaffold and subsequently anchoring reduced graphene oxide (rGO) through a simple impregnation-drying coating method. Regulating the concentration of graphene oxide (GO) impregnation solution can effectively control the rGO loading content for adjusting the EM parameters of PET@rGO composite fabric. When the concentration is 2.0 mg/mL, the as-prepared PET@rGO exhibits the optimum reflection loss (RL) value of −24.53 dB at 12.4 GHz and a corresponding effective absorption bandwidth (EAB, RL≤−10 dB) of 3.20 GHz (9.20–12.40 GHz). The impressive absorption property attributed to the synergistic effect of impedance matching and dielectric loss originated from the three-dimensional (3D) conductive network on fabric interlaced structures. More importantly, stretching PET@rGO composite fabrics to different deformations can dynamically adjust the EM absorption properties while maintaining the knitted structure. This work demonstrates an efficient avenue for the rational design of next-generation EM absorbing fabric, showing latent applications in flexible functional electronics.

Frequency-hopping wave engineering with metasurfaces

Wave phenomena can be artificially engineered by scattering from metasurfaces, which aids in the design of radio-frequency and optical devices for wireless communication, sensing, imaging, wireless power transfer and bio/medical applications. Scattering responses vary with changing frequency; conversely, they remain unchanged at a constant frequency, which has been a long-standing limitation in the design of devices leveraging wave scattering phenomena. Here, we present metasurfaces that can scatter incident waves according to two variables—the frequency and pulse width—in multiple bands. Significantly, these scattering profiles are characterized by how the frequencies are used in different time windows due to transient circuits. In particular, by using more than one frequency with coupled transient circuits, we demonstrate variable scattering profiles in response to unique frequency sequences, which can break a conventional linear frequency concept and markedly increase the available frequency channels in accordance with a factorial number of frequencies used. Our proposed concept, which is analogous to frequency hopping in wireless communication, advances wave engineering in electromagnetics and related fields.

The effects of radiofrequency electromagnetic fields exposure on tinnitus, migraine and non-specific symptoms in the general and working population: A systematic review and meta-analysis on human observational studies

BackgroundApplications emitting radiofrequency electromagnetic fields (RF-EMF; 100 kHz to 300 GHz) are widely used for communication (e.g. mobile phones), in medicine (diathermy) and in industry (RF heaters). ObjectivesThe objective is to systematically review the effects of longer-term or repeated local and whole human body radiofrequency electromagnetic field (RF-EMF) exposure on the occurrence of symptoms. Primary hypotheses were tinnitus, migraine and headaches in relation to RF-EMF exposure of the brain, sleep disturbances and composite symptom scores in relation to whole-body RF-EMF exposure. MethodsEligibility criteria: We included case-control and prospective cohort studies in the general population or workers estimating local or whole-body RF-EMF exposure for at least one week.Information sources: We conducted a systematic literature search in various databases including Web of Science and Medline.Risk of bias: We used the Risk of Bias (RoB) tool developed by OHAT adapted to the topic of this review.Synthesis of results: We synthesized studies using random effects meta-analysis. ResultsIncluded studies: We included 13 papers from eight distinct cohort and one case-control studies with a total of 486,558 participants conducted exclusively in Europe. Tinnitus is addressed in three papers, migraine in one, headaches in six, sleep disturbances in five, and composite symptom scores in five papers. Only one study addressed occupational exposure.Synthesis of results: For all five priority hypotheses, available research suggests that RF-EMF exposure below guideline values does not cause symptoms, but the evidence is very uncertain. The very low certainty evidence is due the low number of studies, possible risk of bias in some studies, inconsistencies, indirectness, and imprecision. In terms of non-priority hypotheses numerous exposure-outcome combinations were addressed in the 13 eligible papers without indication for an association related to a specific symptom or exposure source. DiscussionLimitations of evidence: This review topic includes various challenges related to confounding control and exposure assessment. Many of these aspects are inherently present and not easy to be solved in future research. Since near-field exposure from wireless communication devices is related to lifestyle, a particular challenge is to differentiate between potential biophysical effects and other potential effects from extensive use of wireless communication devices that may compete with healthy behaviour such as sleeping or physical activity. Future research needs novel and innovative methods to differentiate between these two hypothetical mechanisms.Interpretation: This is currently the best available evidence to underpin safety of RF-EMF. There is no indication that RF-EMF below guideline values causes symptoms. However, inherent limitations of the research results in substantial uncertainty. OtherFunding: This review was partially funded by the WHO radioprotection programme.Registration: The protocol for this review has been registered in Prospero (reg no CRD42021239432) and published in Environment International (Röösli et al., 2021)

Attrition in Psychological mHealth Interventions for Young People: A Meta-Analysis

AbstractPsychological interventions provided via mobile, wireless technological communication devices (mHealth) are a promising method of healthcare delivery for young people. However, high attrition is increasingly recognised as a challenge to accurately interpreting and implementing the findings of mHealth trials. The present meta-analysis consolidates this research and investigates potential methodological, sociodemographic, and intervention moderators of attrition. A systematic search of MEDLINE, PsycInfo, and Embase was conducted. Study reporting quality was evaluated (QualSyst tool), and attrition rates (proportions) were calculated and pooled, using both random- and mixed-effects models. The pooled attrition rate, sourced from 15 independent samples (Nparticipants = 1766), was 17% (CI [9.14, 30.13]). This increased to 26% (CI [15.20, 41.03]) when adjusting for publication bias. Attrition was significantly higher among application-based interventions (26%, CI [14.56, 41.86]) compared to those delivered via text or multimedia message (6%, CI [1.88, 16.98]). These data were, however, characterised by significant between-study variance. Attrition in mHealth trials with young people is common but may be mitigated by using message-based interventions. Taken together, the results can provide guidance in accounting for attrition across future mHealth research, clinical practice, public policy, and intervention design. However, sustained research focus on the effectiveness of different engagement strategies is needed to realise mHealth’s promise of equitable and efficient healthcare access for young people globally.

Magnetic field tunable piezoelectric resonator for MEMS applications

In this report, the Ni0.50Mn0.35In0.15/Pb0.96La0.04Zr0.52Ti0.48O3 (Ni-Mn-In/PLZT) bulk acoustic wave (BAW) resonator has been fabricated using the sputtering deposition technique. The magnetoelectric effect in the Ni-Mn-In/PLZT resonator has been investigated. The increase in magnetoelectric coupling coefficient (MECC) with the increment in the frequency of applied HAC is observed. The potential of the Ni-Mn-In/PLZT BAW resonator as a magnetic sensor is tested by measuring the shift in the resonant frequency of the reflective (S11 parameter) response in the presence of the externally applied magnetic field. The Ni-Mn-In/PLZT resonator exhibits a frequency shift of 730 MHz in the 1200 Oe magnetic field, among the largest magnetic field-induced frequency shifts in literature. The rarely reported complete dependence of acoustic velocity, coupling coefficients, magnetic sensitivity, and frequency peak shift on the strength of the external magnetic field is investigated. The acoustic velocity increases from 1237 m/s to 1394 m/s, and the electromechanical coupling coefficient increases from 0.0199 % to 0.0206 % after applying the 1200 Oe magnetic field. The reflective responses have been fitted using the Modified-Butterworth Van Dyke (MBVD) model in terms of hardly reported RLC equivalent circuits. The experimental results and extracted parameters from MBVD modeling exhibit high accuracy. This interaction between multiferroic orders and elastic resonance peaks opens a new window for highly sensitive future magnetic field sensors, wireless communication devices, and magnetic field tunable filters.

Hexagonal Microstrip Patch Antenna with Defective Ground Structure for Wideband Applications

The complexity and variety of modern wireless communication devices have resulted in an increase in the need for high-performance and wideband antennas. This research proposes an innovative approach for enhancing the bandwidth of hexagonal patch antennas using a microstrip line feed and the Defected Ground Structure (DGS) technology. The area of the hexagonal patch with defective ground structure wideband antenna is 32×24 mm2. The wideband ability and compact dimensions of the hexagonal patch antenna make it attractive. The DGS approach is used to change the resonant behavior of the antenna, resulting in a significant bandwidth enhancement. The simulation results demonstrate that combining DGS with the microstrip feed leads to significant enhancements in gain, radiation characteristics, and impedance bandwidth. The approach has potential for a range of wireless communication applications that demand wide performance in a compact antenna design.

High radiation performance and multi-band acoustically driven piezoelectric antenna based on energy trapping theory

The paper introduces a novel design method for an acoustically driven piezoelectric antenna with high radiation performance and broadband characteristics based on energy trapping theory. The reasonableness of the design method is demonstrated by analytically deriving the radiated magnetic field, radiated efficiency and resonant frequency, which are further validated by simulation analysis. Furthermore, a prototype is fabricated and measured, and the results indicate remarkable improvements compared to the non-energy trapping mode, the bandwidth is widened by 10%, the radiation efficiency is increased by 28%, the radiation magnetic field is increased by three times, the transmission distance is increased by 2.75 times. The radiation enhancement and multi-band capability of the proposed antenna has been successfully demonstrated. Additionally, we have successfully implemented amplitude modulation signals transmission using proposed antenna. These results highlight the significant potential of the proposed antenna for portable, miniaturized, and high-performance wireless communication devices.

4G based SAR analysis for anatomically based human head model using mobile phone antenna

Mobile phone handsets utilized by individuals of all ages been heavily grows popular as a wireless communication device. Every mobile phone produces electromagnetic radiation at radio frequencies (RF). The specific absorption rate is used to calculate how much of this energy is absorbed by the human skull. Standard guidelines state that sold phones must fall below a specified SAR. This paper aims to evaluate the Specific Absorption Rate (SAR) and E-field strength for mobile phone radiation exposure on a head model who is 40 years old and a 5-year-old child. The human skull is represented in this model as a six-layered sphere made up of the brain, CSF, dura, bone, fat, and skin. Various layers of the head's SAR distribution have been measured as an impact of radiation from mobile phones exposure using the 1800 MHz frequency. Earlier research were used to consider the dielectric properties of tissue layers. The human head and mobile phone antenna is modelled in this research using ANSYS HFSS. A hand-held mobile phone's dipole antenna type is considered for RF exposure. It is seen how EM absorption in various tissue layers for both adults as well as child head. SAR comparisons between the adult and child head reveal that the child head absorbs greater power due to the distinctive layerwise head shape, conductivity, permittivity, and permeability of the two head models. Excess EM absorption may have negative physiologic implications for human health specifically impact on child physical and mental health.