Specific Absorption Rate Values Research Articles

A dual‐band dual‐polarized omnidirectional patch antenna for on‐body application

AbstractAiming at the 3.5 GHz world interoperability for microwave access band and 5.8 GHz industrial scientific medical band, a dual‐band antenna operating in omnidirectional mode is proposed. The antenna uses a single‐layer dielectric substrate made of FR‐4, which is cheap and easy to process. It uses circular patches and metal branches to generate orthogonal electric fields to achieve circular polarization. At the same time, the upper patch is symmetrically slotted in a T shape, so that the patch produces two resonance frequencies. The measured impedance bandwidth of the antenna in circular polarization on‐body mode and linear polarization on‐body mode is 110 MHz (3.41–3.52 GHz) and 460 MHz (5.42–5.88 GHz), respectively. In addition, the antenna shows good performance under bending conditions and close to human tissue. At the same time, the low specific absorption rate value proves that the antenna is safe to wear on the human body.

Implanted Rhombus Ring Partial Inset-Fed Circularly Polarized Microstrip Monopole Antenna for WBAN Applications

In the present article, a design approach to accomplish circular polarization-based rhombus ring microstrip-fed monopole antenna working at 5.8 GHz for wireless body area network (WBAN) applications is proposed. The input impedance calculation using an electromagnetic theory of transmission line in a travelling wave coupled to the parallel-plate inductor model is conducted. Radiated electric field pattern calculation of the conventional square ring microstrip patch antenna (MSPA) using Biot and Savart’s law is reported. The circular polarization of the proposed antenna is accomplished by loading the radiating path with a capacitive element sectioned in the neighbourhood of the feed line. The proposed planar monopole antenna of volume 0.38λ0×0.38λ0×0.029λ0 (λ0 is evaluated at the resonant frequency of 5.8 GHz) achieves a -10 dB impedance bandwidth of 86.20% in the band (3-8 GHz) with a stable real gain of 8.29 dBic in circular polarization at the resonant frequency of 5.8 GHz and axial ration bandwidth of about 32.75% in the (5-6.9 GHz) band. Specific absorption rate (SAR) evaluation of the studied antenna is computed numerically on a part of the human phantom model to justify its use in WBAN applications. It is noted that the maximum amount of radiation absorbed by a part of the human phantom model is limited to a maximum SAR value of 1.45 W/kg and 0.754 W/kg on 1 g and 10 g of tissue mass, respectively. The prospective design has been fabricated and tested, and the experimental results are in good agreement with the simulation outcomes.

Design and Analysis of a Quad-Band Antenna for IoT and Wearable RFID Applications

The role of antennas in wireless communication is critical for enabling efficient signal transmission and reception across various frequency bands, including those associated with IoT (Internet of Things), X-band, S-band, and RFID (radio-frequency identification) systems. This paper presents a small quadruple-band antenna with 25 × 40 × 1.5 mm3 dimensions designed for diverse wireless applications. It is adept at operating in the S-band (2.2 GHz), wireless local area network (WLAN) (5.7 GHz), microwave RFID frequency band (5.8 GHz), and X-band (7.7 GHz and 8.3 GHz). While the majority of existing research focuses on antennas covering two or three bands, our work stands out by achieving quad-band operation in the proposed antenna design. This antenna is constructed on a semiflexible Rogers RT5880 substrate, making it well-suited for wearable applications. Computer Simulation Technology (CST) Microwave studio (2019) simulation package software is chosen for design and analysis. The antenna design features a comb-shaped radiating structure, where each “tooth” is responsible for resonating at a distinct frequency with an appropriate bandwidth. The antenna retains stability in both free space and on-body wearability scenarios. It achieves a low specific absorption rate (SAR), meeting wearable criteria with SAR values below 1.6 W/Kg for all resonating frequencies. The proposed antenna demonstrates suitable radiation efficiency, reaching a maximum of 82.6% and a peak gain of 6.3 dBi. It exhibits a bidirectional pattern in the elevation plane and omnidirectional behavior in the azimuth plane. The antenna finds applications across multiple frequencies and shows close agreement between simulated and measured results, validating its effectiveness.

Development of experimental device for inductive heating of magnetic nanoparticles

Inductive heating using magnetic nanoparticles is a critical process extensively investigated for cancer treatment. However, the high cost of commercially available equipment hinders its accessibility for many research groups. In response, this paper introduces a simple electronic circuit with low-cost components, making it easy to construct even for non-electronic experts. Operating within the 50–200 kHz range, the circuit employs a parallel inductor-capacitor configuration, providing a maximum induction magnetic field of 23.6 mT. Ltspice software simulations align well with oscilloscope measurements. Using commercial iron oxide nanoparticles (∼16 nm) in water suspensions (1–10 mg ml−1), the device exhibited a concentration-dependent reduction in specific absorption rate values, consistent with literature findings. Hyperthermia temperatures were achieved in a few minutes at 52.5 kHz and 23.6 mT in the highest concentration. At 81.9 kHz and 21.5 mT, a temperature of 93 °C was achieved after 22 min at 10 mg ml−1. Additionally, the device demonstrated stable and safe operation over a 100 min period, as validated by an ice-melting experiment. These results highlight the device’s efficacy for hyperthermia experiments in both biological and non-biological systems, particularly advantageous for larger nanoparticles in a blocked state. The proposed device holds significant potential for contributing to hyperthermia studies across diverse research groups. Future development will focus on frequency adjustment without reducing the alternating magnetic field amplitude and a thorough investigation of field homogeneity inside the coils.

Preparation of stable colloidal dispersion of surface modified Fe3O4 nanoparticles for magnetic heating applications

The effect of surface modification on enhancing the magnetic heating behavior of magnetic nano fluids were investigated, for this purpose Fe3O4 nanoparticles were synthesized using co-precipitation method and surface modification was done using citric acid, ascorbic acid, tetraethyl orthosilicate (TEOS), polyvinyl alcohol (PVA) and polyethylene glycol (PEG). Experimental heating tests using AC magnetic field were done in the frequency of 100 kHz and different magnetic field (H) intensities. Theoretically the specific absorption rate (SAR) in magnetic nano fluids is independent of nanoparticles concentration but the experimental results showed different behavior. The theoretical SAR value @ H = 12kA.m–1 for Nano fluids containing bare Fe3O4 nanoparticles was 11.5 W/g but in experimental tests the obtained value was 9.72 W/g for nano fluid containing 20,000 ppm of dispersed nanoparticles. The experimental SAR calculation was repeated for sample containing 10,000 ppm of nanoparticles and the results showed increase in experimental SAR that is an evidence of nanoparticles agglomeration in higher concentrations. The surface modification has improved the dispersion ability of the nanoparticles. The Ratio of SAR, experimental, 20000ppm to SAR, experimental, 10000ppm was 0.85 for bare Fe3O4 nanoparticles dispersion but in case of surface modified nanoparticles this ratio has increased up to 0.98 that shows lower agglomeration of nanoparticles as a result of surface modification, although on the other hand the surface modification agents were magnetically passive and so it is expected that in constant concentration the SAR for bare Fe3O4 nanoparticles to be higher than this variable for surface modified nanoparticles. At lower concentrations the dispersions containing bare Fe3O4 nanoparticles showed higher SAR values but at higher concentrations the surface modified Fe3O4 nanoparticles showed better results although the active agent amount was lower at them. Finally, it should be noted that the nanoparticles that were surface modified using polymeric agents showed the highest decrease in experimental SAR amounts comparing theoretical results that was because of the large molecules of polymers comparing other implemented surface modification agents.

A very low-profile CPW based conformal antenna for wearable/implantable applications.

In wireless communication standard 4G and 5G, the body centric network plays an important role for the wireless communication between various devices. This research relates to a wide-band conformal co-planar waveguide (CPW) antenna for wearable applications. The proposed CPW antenna is printed on 0.1 mm thick bio-compatible polymide substrate whose dielectric constant and permittivity are 3.5 and 0.02 respectively. The total area of the antenna is around 17.5 × 15 mm2 which is significantly smaller than the wearable antennas proposed in literature. The proposed antenna is designed to operate in new ISM band 5.8 GHz with the bandwidth of 5.3-6.3 GHz with 2:1 Voltage Standing Wave Ratio (VSWR). The antenna is printed on the flexible substrate and hence robustness of device is evaluated by bending analysis. It reveals the superior performance of the designed CPW antenna over the desired spectrum of operation. Specific Absorption Rate (SAR) is calculated after placing the antenna at various places of human phantom model and showed that SAR values are below 1.6 W/Kg which is the maximum margin recommended by Federal Communication Commission (FCC), i.e when tested with 1 g and 10 g of human tissue of phantom model, for the test frequency range of 5.5-6.1GHz, SAR value falls between 0.9987 and 0.921 W/Kg respectively. The antenna also shows the radiation efficiency around 92% with overall realized gain 5.2 dBi which are substantial values for wearable applications. The outcomes of this research revealed the feasibility of the recommended antenna becoming a major contender of future Internet of Things (IoT) applications.

Opto-magnetic nanoparticles with upconverting properties for optical imaging and photothermal therapies

Multifunctional opto-magnetic nanoparticles (NPs) with upconverting properties were designed for cancer detection and treatment. The upconversion was achieved from NaYF4 doped by 20 %Yb and 2 % Er nanoparticles (UCNPs). The UCNPs were coated by a thin SiO2 shell and decorated with 6 nm magnetic Fe3O4 that resulted in the formation of NaYF4:Yb,Er@SiO2@Fe3O4 multifunctional nanoplatform. The connection between UCNPs and Fe3O4 NPs was proved by SEM, TEM, SQUID, absorption, and luminescence techniques. The specific absorption rate (SAR) values for prepared colloids were calculated for colloidal suspension of heterostructures after 808 and 880 nm laser irradiation as a function of lasers power. The highest conversion effectiveness was obtained for an 880 nm light source with 1600 mW (SAR = 87 W/g). The low MDA-MB-231 cells cytotoxicity of NaYF4:Yb,Er@SiO2@Fe3O4 NPs was observed (up to 500 µg/ml). At the same time, a strong upconverting signal after 980 nm of excitation was observed from the sites of the cells without autofluorescence from its components. This phenomenon with relatively good SAR parameters suggested that multifunctional nanoconstructs for simultaneous cancer detection (imaging) and photothermal therapy have been successfully obtained.

On the Evaluation of the Hyperthermic Efficiency of Magnetic Scaffolds.

Goal: Deep-seated tumors (DST) can be treated using thermoseeds exposed to a radiofrequency magnetic field for performing local interstitial hyperthermia treatment (HT). Several research efforts were oriented to the manufacturing of novel biocompatible magnetic nanostructured thermo-seeds, called magnetic scaffolds (MagS). Several iron-doped bioceramics or magnetic polymers in various formulations are available. However, the crucial evaluation of their heating potential has been carried out with significantly different, lab specific, variable experimental conditions and protocols often ignoring the several error sources and inaccuracies estimation. Methods: This work comments and provides a perspective analysis of an experimental protocol for the estimation methodology of the specific absorption rate (SAR) of MagS for DST HT. Numerical multiphysics simultions have been performed to outline the theoretical framework. After the in silico analysis, an experimental case is considered and tested. Results: From the simulations, we found that large overestimation in the SAR values can be found, due to the axial misplacement in the radiofrequency coil, while the radial misplacement has a lower impact on the estimated SAR value. Conclusions: The averaging of multiple temperature records is needed to reliably and effectively estimate the SAR of MagS for DST HT.

ENHANCING WEARABLE AND MEDICAL CONNECTIVITY: A NOVEL PRINTED TRIPLE-BAND METAMATERIAL ANTENNA FOR WBAN/MBAN APPLICATIONS

This paper presents a novel, compact, monopole apple-shaped, and triple-band metamaterial printed antenna for wireless body area network (WBAN) and medical body area network (MBAN) applications. The antenna is backed by a tri-band uniplanar compact electromagnetic bandgap (UC-EBG) structure that acts as a ground plane and incorporates metamaterial triangular complementary splitring resonators (TCSRRs). The proposed printed textile antenna operates at 2.45 GHz for wireless local area network (WLAN), 3.5 GHz for 5G new radio (NR), and 5.8 GHz for industrial, scientific, and medical bands. Implementing the UC-EBG structure resulted in a 99% decrease in the specific absorption rate (SAR) values over 1 g and 10 g of tissues and achieved gains of 5.45, 6.09, and 7.63 dBi at 2.45, 3.5, and 5.8 GHz, respectively. Due to its high performance, low SAR values, and compact size of 39 × 39 × 2.84 mm<sup>3</sup> (0.41 λ<sub>g</sub> × 0.41 λ<sub>g</sub> × 0.029 λ<sub>g</sub> ), the proposed antenna is an attractive candidate for wearable healthcare, fitness monitoring devices, and other WBAN/MBAN applications.

A 9.73 GHz wide-band off-body patch antenna for biomedical applications

<span>The primary goal of this study is to design a simple antenna that has a wide bandwidth and low return loss for biomedical applications. The paper shows the recommended antenna’s three-stage modeling, with the goal of assessing every important parameter while a Teflon or polytetrafluoroethylene (PTFE) polymer substrate is used. In order to better comprehend, a comparison with prior studies employing teflon and similar substrate materials is conducted for the proposed patch antenna. The analysis includes the phantom model, evaluating performance criteria such as specific absorption rate (SAR), return loss, bandwidth, and gain values relevant to biomedical applications. The antenna works at two different frequencies: 9.73 and 9.39 GHz, one in free space and another in a skin-cotton layer. The bandwidth of the antenna is 4.067 GHz in free space at the resonance frequency of 9.73 GHz, where the return loss is -62.18 dB. The performance of the proposed antenna in the field of biomedical applications, its underlying reasons, and its impacts are discussed in detail in this study.</span>

ADVANCED ULTRAWIDEBAND PATCH ANTENNA FOR WEARABLE AND WBAN APPLICATIONS

Present communication devices are adopting an application-centric approach with the integration of electronic gadgets into wearable accessories in recent years. This paper presents a wearable antenna with a flexible textile substrate. The design comprises a low-profile, textile-based UWB (3.1-10.6 GHz) antenna of 25 × 20 × 1 mm<sup>3</sup> size with a defected ground structure. Design antenna performance characteristics have been simulated in Computer Simulation Technology studio. It offers a gain of 4.204 dBi at 5.11 GHz frequency and 2.993 dBi at 7.39 GHz frequency using a cotton substrate with a 1.6 dielectric constant. A simulated testing of the design antenna on a human body phantom has resulted in a gain of 0.697 dBi with a return loss of -30.863dB and 1.058 VSWR at 5.3125 GHz frequency. A specific absorption rate value of 1.64 W/kg of the designed antenna for 10 g tissue shows that it is safe for the human body. The patch antenna of the paper is promising for wearable, medical imaging, tumor detection, and other wireless body area network (WBAN) biomedical applications.

Design and performance investigation of metamaterial-inspired dual band antenna for WBAN applications.

This paper presents the design and analysis of a metamaterial-based compact dual-band antenna for WBAN applications. The antenna is designed and fabricated on a 0.254 mm thick semi-flexible substrate, RT/Duroid® 5880, with a relative permittivity of 2.2 and a loss tangent of 0.0009. The total dimensions of the antenna are 0.26λo×0.19λo×0.002λo, where λo corresponds to the free space wavelength at 2.45 GHz. To enhance overall performance and isolate the antenna from adverse effects of the human body, it is backed by a 2×2 artificial magnetic conductor (AMC) plane. The total volume of the AMC integrated design is 0.55λo×0.55λo×0.002λo. The paper investigates the antenna's performance both with and without AMC integration, considering on- and off-body states, as well as various bending conditions in both E and H-planes. Results indicate that the AMC-integrated antenna gives improved measured gains of 6.61 dBi and 8.02 dBi, with bandwidths of 10.12% and 7.43% at 2.45 GHz and 5.80 GHz, respectively. Furthermore, the AMC integrated antenna reduces the specific absorption rate (SAR) to (>96%) and (>93%) at 2.45 GHz and 5.80 GHz, meeting FCC requirements for low SAR at both frequencies when placed in proximity to the human body. CST Microwave Studio (MWS) and Ansys High-Frequency Structure Simulation (HFSS), both full-wave simulation tools, are utilized to evaluate the antenna's performance and to characterize the AMC unit cell. The simulated and tested results are in mutual agreement. Due to its low profile, high gain, adequate bandwidth, low SAR values, and compact size, the AMC integrated antenna is considered suitable for WBAN applications.

Risk factors of congenital anomalies of the kidney and urinary tract (CAKUT): Exposure to mobile phones during pregnancy.

Congenital anomalies of the kidney and urinary tract(CAKUT) are the leading causes of childhood chronic kidney disease (CKD). The etiology of most of the cases is thought to be multifactorial. In this study, risk factors for CAKUT and the effect of mobile phone-related electromagnetic field (EMF) exposure during pregnancy were investigated. Fifty-seven cases and 57 healthy controls under 2 years of age were included and their mothers were subjected to a questionnaire. Groups were compared for parents' demographics, pregestational (chronic disease, body mass index, use of the folic acid supplements) and antenatal variables (gestational disease, weight gain during pregnancy,) and exposures during pregnancy. To assess mobile phone-related radiation exposure, all participants were asked about their daily call time, the proximity of the phone when not in use, and the models of their mobile phones. The specific absorption rate (SAR) of the mobile phones and the effective SAR value (SAR × call time) as an indicator of EMF exposure were recorded. Excess weight gain according to BMI during pregnancy was related to an increased risk of CAKUT (p=0.012). Folic acid use before pregnancy was protective for CAKUT (p = 0.028). The call time of mothers of the CAKUT group was significantly longer than the control (p = 0.001). An association was observed between higher effective SAR values and increased risk of CAKUT (p = 0.03). However the proximity of the mobile phone to the mother's body when not in use was not found as a risk factor. The etiology of CAKUT is multifactorial. Our results suggest that prolonged phone call and higher EMF exposure during pregnancy increases the risk of CAKUT in the offspring.

Design of Antipodal Vivaldi Antenna for Medical Imaging Application

The microwave imaging (MWI) system in medical applications is commonly used to detect abnormalities in the human body. The purpose of this study was to design an Antipodal Vivaldi Antenna (AVA) for medical imaging applications using MWI. The research method used is based on the AVA design simulation of the CST Studio Suite 2019 application using time and frequency domain methods, which has dimensions of 60x40 mm2 with an antenna structure that works in the frequency range of 6.3-9.6 GHz, the impedance for bandwidth is -10 dB, using Flame Retardant-4 (FR-4) thickness 1.6 mm (= 4.3, tan δ = 0.025) as substrate material. A linear array of antennas was utilized in the simulation, either with or without a phantom. The phantom options include an absence of a phantom (only antennas), a cube-shaped water phantom, and a water phantom containing an anomaly. The result of the simulation on the AVA design produces a bandwidth of 41.61%, a gain of 5.16 dB, a return loss of -26.73 dB, a Specific Absorption Rate (SAR) value of 0.26 W/kg and a graph of S-parameters (S21). It can be concluded that the MWI system using the AVA design in this study has the potential to properly detect the presence of anomalies.

Flexible Metal-Dielectric metasurface for 3-Tesla MRI image enhancement

In this paper, we present a numerical investigation of metal-dielectric metasurface to improve the image quality of a 3-Tesla Magnetic Resonance Imaging system. The designed metasurface consists of non-magnetic copper strips placed in a circular fashion on a high dielectric substrate. The eigenmode analysis of the designed metasurface shows the fundamental eigenmode at a resonant wavelength of 127 Megahertz, which corresponds to the operating frequency of 3-Tesla Magnetic Resonance Imaging. When metasurface is investigated under the presence of an electromagnetic field, it is observed that the magnetic field redistributes at the centre of the metasurface and paves the way for better image quality. The three voxel simulation scenarios—the first with a metasurface, the second with just a dielectric pad, and the third with “no surface”—were compared in the numerical simulation. It is found that the proposed metasurface significantly reduces the Specific Absorption Rate value and increases the magnetic field in the area of interest by 1.5 times compared to the dielectric pad and by more than double compared to the “no surface” scenario.

The effect of frequency (64-498MHz) on specific absorption rate adjacent to metallic orthopedic screws in MRI: A numerical simulation study.

The imaging of patients with implanted electrically-conductive devices via magnetic resonance imaging at ultra-high fields is hampered by uncertainties relating to the potential for inducing tissue heating adjacent to the implant due to coupling of energy from the incident electromagnetic field into the implant. Existing data in the peer-reviewed literature of comparisons across field strengths of tissue heating and its surrogate, the specific absorption rate (SAR), is scarce and contradictory, leading to further doubts pertaining to the safety of imaging patients with such devices. The radiofrequency-induced SAR adjacent to orthopedic screws of varying length and at frequencies of 64 to 498MHz was investigated via full-wave electromagnetic simulations, to provide an accurate comparison of SAR across MRI field strengths. Dipole antennas were used for RF transmission to achieve a uniform electric field tangential to the screws located 120mm above the antenna midpoints, embedded in a bone-mimicking material. The input power to the antennas was constrained to achieve the following targets without the screw present: (i) E=100V/m, (ii) B1 + =2 μT, and (iii) global-average-SAR=3.2W/kg. Simulations were performed with a spatial resolution of 0.2mm in the volume surrounding the screws, resulting in 76-137 MCells, noting the maximum 1g-averaged SAR value in each case. Simulations were repeated at 128 and 297MHz for screws embedded in muscle tissue. The peak SAR, occurring at the resonant screw length, substantially increased as the frequency decreased when the input power to the dipole antenna was constrained to achieve constant electric field in background tissue at the screws' locations. A similar pattern was observed when constraining input power to achieve constant B1 + and global-average-SAR. The dielectric properties of the tissue in which the screws were embedded dominated the SAR comparisons between 297 and 128MHz. The study design allowed for a direct comparison to be performed of SAR across frequencies and implant lengths without the confounding effect of variable incident electric field. Lower frequencies produced substantially larger SAR values for implants approaching the resonant length for the worst-case uniform incident electric field along the screws' length. The data may inform risk-benefit assessments for imaging patients with orthopedic implants at the new clinical field strength of 7Tesla.

Interplay of Anisotropy Energy Barrier and Self-Heating Efficiency of Cobalt-Substituted CuFe2O4 Nanoparticles.

In this study, we delve into the intricate interplay between the anisotropy energy barrier and the self-heating efficiency of magnetic nanoparticles (MNPs). We embarked on this exploration by synthesizing Cu1-xCoxFe2O4 (x = 0, 0.1, 0.3, and 0.5) MNPs using a straightforward coprecipitation method. Our magnetic assessments, conducted at different temperatures, unveiled a notable trend as we traversed from x = 0.1 to x = 0.5. Specifically, we observed a consistent increase in saturation magnetization, coercivity, and remanence. This pattern also extended to the anisotropy energy barrier, which was derived from the effective anisotropy constant determined through the temperature dependency of the coercivity method. However, an intriguing twist emerged when we scrutinized the specific absorption rate (SAR), calculated via the Box-Lucas method. Contrary to much of the existing literature, our experimental results showcased a decline in SAR concerning x. This experimental work challenges the conventional understanding of the relationship between the anisotropy energy barrier and the SAR value of these nanoparticles. This study prompts us to reconsider the intricate mechanisms governing the relaxation of magnetic moments and subsequent heat release when subjected to an alternating magnetic field. By doing so, we aim to gain fresh insights into the self-heating properties of MNPs and optimize their utilization to better understand their heat-release properties and ensure that they are used as efficiently as possible in a variety of biomedical applications.

Biosynthesis, characterization, magnetic hyperthermia, and in vitro toxicity evaluation of quercetin-loaded magnetoliposome lipid bilayer hybrid system on MCF-7 breast cancer

Novel biocompatible and effective hyperthermia (HT) treatment materials for breast cancer therapeutic have recently attracting researchers, because of their effective ablation of cancer cells and negligible damage to healthy cells. Magnetoliposome (MLs) have numerous possibilities for utilize in cancer treatment, including smart drug delivery (SDD) mediated through alternating magnetic fields (AMF). In this work, magnesium ferrite (MgFe2O4) encapsulated with liposomes lipid bilayer (MLs), Quercetin (Q)-loaded MgFe2O4@Liposomes (Q-MLs) nano-hybrid system were successfully synthesized for magnetic hyperthermia (MHT) and SDD applications. The hybrid system was well-investigated by different techniques using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), Energy dispersive X-ray (EDX), Vibrating sample magnetometer (VSM), Transmission electron microscope (TEM), and Zeta Potential (ZP). The characterization results confirmed the improving quercetin-loading on the MLs surface. TEM analysis indicated the synthesized MgFe2O4, MLs, and Q-MLs were spherical with an average size of 23.7, 35.5, and 329.5 nm, respectively. The VSM results revealed that the MgFe2O4 exhibit excellent and effective saturation magnetization (MS) (40.5 emu/g). Quercetin drug loading and entrapment efficiency were found to be equal to 2.1 ± 0.1% and 42.3 ± 2.2%, respectively. The in-vitro Q release from Q-loaded MLs was found 40.2% at pH 5.1 and 69.87% at pH 7.4, verifying the Q-loading pH sensitivity. The MLs and Q-MLs hybrid system as MHT agents exhibit specific absorption rate (SAR) values of 197 and 205 W/g, correspondingly. Furthermore, the Q-MLs cytotoxicity was studied on the MCF-7 breast cancer cell line, and the obtained data demonstrated that the Q-MLs have a high cytotoxicity effect compared to MLs and free Q.

Design and Analysis of Fabric Antenna for Medical and Wireless Applications

This study aimed toward the wearability of the antenna by inspecting the probability of designing and fabricating a wearable microstrip antenna operating from 2 to 6 GHz, centered at 2.5 GHz and 5.3 GHz. The antenna is fabricated from jeans material with dielectric constant εr = 1.7 and a thickness of 1 mm. The proposed design is simulated on High-Frequency Simulation Software (HFSS) version 2015, followed by fabrication using a 50-µm copper film on a jeans substrate. Anritsu MS2038C VNA Master then tests the fabricated design. Also, specific absorption rate (SAR) values are computed for medical applications to account for tumor detection in human breast tissue.

Investigation of SAR reduction and gain enhancement using an all-textile antenna with metamaterial structure for wireless body area network applications

This work presents a wideband, low-profile, and flexible antenna that incorporates metamaterial (MTM) structures and textile materials. The antenna design is simulated using CST Microwave Studio, incorporating flexible textile elements such as a felt substrate and conductive fabric. The developed antenna's performance was examined numerically in free space and on a human body. The antenna with MTM technology operates in the ultra-wideband (UWB) with a bandwidth ranging from 3.86 to 13 GHz. It possesses a low profile with a thickness of 5.34 mm, making it suitable for applications in wireless body area networks (WBAN). Through the integration of metamaterial structures, the antenna's gain is enhanced, reaching 8.85 dBi compared to the initial gain of 5.34 dBi. Notably, the gain consistently exceeds 6 dBi across the entire UWB range, indicating focused power in a specific direction. For applications on the human body, specific absorption rate (SAR) values were calculated and found to be well within safety limits defined by European standards. This ensures minimal back radiation when the antenna is worn on the body, enhancing signal transmission range in WBAN applications.