Simulated Specific Absorption Rate Research Articles

A Wearable All-Printed Textile-Based 6.78 MHz 15 W-Output Wireless Power Transfer System and Its Screen-Printed Joule Heater Application

While research in passive flexible circuits for Wireless Power Transfer (WPT) such as coils and resonators continues to advance, limitations in their power handling and low efficiency have hindered the realization of efficient all-printed high-power wearable WPT receivers. Here, we propose a screen-printed textile-based 6.78 MHz resonant inductive WPT system using planar inductors with concealed metal-insulator-metal (MIM) tuning capacitors. A printed voltage doubler rectifier based on Silicon Carbide (SiC) diodes is designed and integrated with the coils, showing a power conversion efficiency of 80-90% for 2-40 W inputs over a wide load range. Compared to prior wearable WPT receivers, it offers an order of magnitude improvement in power handling along with higher efficiency (approaching 60%), while using all-printed passives and a compact rectifier. The coils exhibit a simulated Specific Absorption Rate (SAR) under 0.4 W/kg for 25 W received power, and under 21 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C increase in the coils' temperature for a 15 W DC output. Additional fabric shielding is investigated, reducing harmonics emissions by up to 17 dB. We finally demonstrate a wirelessly-powered textile-based carbon-silver Joule heater, capable of reaching up to 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C at 2 cm separation from the transmitter, as a wearable application which can only be wireless-powered using the proposed system.

Terahertz Microstrip Patch Antenna for Breast Tumour Detection

Breast cancer is one of the most common cancers among Malaysian women. It is critical to discover strategies to detect the tumour early on. Terahertz (THz) frequency provides excellent qualities for detecting tumours such as low photon energy and non-ionising radiation as compared to prior methods such as mammography, ultrasound, and magnetic resonance imaging (MRI) that use optical to X-ray frequencies. The purpose of this work is to analyse and locate a breast tumour as well as to compute the maximum specific absorption rate (SAR) value. It was designed a THz rectangular microstrip patch antenna with an inset feed. To improve the antenna's performance, graphene was used for the patch and polyimide for the substrate. This antenna covered a bandwidth of 31.6 GHz and worked in the frequency range of 0.283-0.599 THz. To identify the location of a tumour, compute the SAR value, and localise the tumour, SAR simulation was used. The maximum SAR shifted to the tumor's position due to greater absorption rate around its tissue due to higher dielectric constant features. It was calculated that 1e-05g of average mass is required to be less than total tissue mass, which is 2.0063e-05g. SAR study revealed a maximum SAR value of 2.49391e+06 W/kg, which was not more than the overall absorption rate for human body safety. The SAR calculation result revealed that the tumour is within the range of the tumor's initial location.

Multiband and Low-Specific-Absorption-Rate Wearable Antenna With Low Profile Based on Highly Conductive Graphene Assembled Film

A flexible tri-band antenna with low profile and low specific absorption rate (SAR) based on highly conductive graphene assembled film (GAF) is proposed. The antenna incorporates GAF with polydimethylsiloxane (PDMS) to provide the flexibility for wearable applications. To reduce the effect of backward radiation on human body, a new multi-band artificial magnetic conductor (AMC) reflector is proposed, which consists of several circular patches. The measured operating bandwidths of GAF antenna include 2.26-2.46 GHz (WiFi band), 3.52-3.68 GHz (5G n77 band) and 4.94-5.26 GHz (5G WLAN band). Correspondingly, the realized gain varies from 5.7-7.9 dBi. The proposed GAF antenna shows good flexibility and radiation stability when loaded on human body. The simulated SAR peak value is 0.51 W/kg at 2.36 GHz, 0.61 W/kg at 3.6 GHz and 0.562 W/kg at 5.1 GHz when the tissue is 1 g, which meets the international standard. All results demonstrate that the proposed flexible GAF tri-band antenna is suitable for integrating in wireless wearable communication system.

A theoretical and experimental investigation on a volume coil with slotted end-rings for rat MRI at 7 T

ObjectiveA volume coil with squared slots-end ring was developed to attain improved sensitivity for imaging of rat’s brain at 7 T.Material and MethodsThe principles of the high cavity resonator for the low-pass case and the law of Biot-Savart were used to derive a theoretical expression of B_1/i. The slotted-end ring resonator showed a theoretical 2.22-fold sensitivity improvement over the standard birdcage coil with similar dimensions. Numerical studies were carried out for the electromagnetic fields and specific absorption rates for our coil and a birdcage coil loaded with a saline-filled spherical phantom and a digital brain of a rat.ResultsAn improvement of the signal-to-noise ratio (SNR) can be observed for the slotted volume coil over the birdcage regardless of the load used in the electromagnetic simulations. The specific absorption rate simulations show a decrement for the digital brain and quite similar values with the saline solution phantom. Phantom and rat’s brain images were acquired at 7 T to prove the viability of the coil design. The experimental noise figure of our coil design was four times less than the standard birdcage with similar dimensions, which showed a 44.5% increase in experimental SNR.DiscussionThere is remarkable agreement among the theoretical, numerical and experimental sensitivity values, which all demonstrate that the coil performance for MR imaging of small rodents can be improved using slotted end-rings.

A design of dual band wearable MIMO antenna using Organza fabric for medical applications

A novel wearable dual-band MIMO antenna featuring good conformal characteristics under bending conditions is presented. The dielectric part of the antenna is built on a flexible substrate using layered lightweight plain weave fabric Organza with a relative permittivity of 1.63 to achieve a low-light and flabby textile. A defected ground structure (DGS) is employed for improving diverse parameters such as narrow bandwidth and resonant adjusting. The DGS part of the antenna is a resonant slot in the ground layer, placed directly under the patches. The electromagnetic energy is transmitted to the radiating slots using a recessed microstrip line feed along with semi co-planar waveguide (CPW) structure with defective ground metal in the bottom layer. It is worthwhile to point out that using the highly flexible Organza fabric with the ability to change the substrate thickness provided acceptable antenna characteristics under the bending condition in different directions. To validate the design, a prototype antenna is fabricated and experimentally investigated. The effect of substrate thickness on antenna performance is investigated by changing the number of Organza layers in both simulation and experiments. A good agreement is attained between the simulation results and the measurement results. The antenna properties such as scattering parameters, radiation patterns, and SAR values are investigated under bending conditions. Results show that the maximum measured gain is 7.8 dB at 2.4 GHz and 7.3 dB at 5 GHz. The simulated specific absorption rate (SAR) values are less than 0.336 W/Kg and 0.468 W/Kg at 2.4 GHz and 5 GHz for 1 g human body tissue, respectively. The SAR values for the bent antenna are less than 0.302 W/Kg and 0.458 W/Kg at 2.4 GHz and 5 GHz for 1 g human body tissue, respectively.

Tier-based formalism for safety assessment of custom-built radio-frequency transmit coils.

The purpose of this work is to propose a tier-based formalism for safety assessment of custom-built radio-frequency (RF) coils that balances validation effort with the effort put in determinating the safety factor. The formalism has three tier levels. Higher tiers require increased effort when validating electromagnetic simulation results but allow for less conservative safety factors. In addition, we propose a new method to calculate modeling uncertainty between simulations and measurements and a new method to propagate uncertainties in the simulation into a safety factor that minimizes the risk of underestimating the peak specific absorption rate (SAR). The new safety assessment procedure was completed for all tier levels for an eight-channel dipole array for prostate imaging at 7 T and an eight-channel dipole array for head imaging at 10.5 T, using data from two different research sites. For the 7 T body array, the validation procedure resulted in a modeling uncertainty of 77% between measured and simulated local SAR distributions. For a situation where RF shimming is performed on the prostate, average power limits of 2.4 and 4.5 W/channel were found for tiers 2 and 3, respectively. When the worst-case peak SAR among all phase settings was calculated, power limits of 1.4 and 2.7 W/channel were found for tiers 2 and 3, respectively. For the 10.5 T head array, a modeling uncertainty of 21% was found based on B1 + mapping. For the tier 2 validation, a power limit of 2.6 W/channel was calculated. The demonstrated tier system provides a strategy for evaluating modeling inaccuracy, allowing for the rapid translation of novel coil designs with conservative safety factors and the implementation of less conservative safety factors for frequently used coil arrays at the expense of increased validation effort.

Wideband Fabric Antenna for Ultra Wideband Applications using for Medical Applications

Traditional cancer detection imaging techniques suffer high costs, high false negatives, high false positives,and pain. The microwave imaging techniques overcome the limitations, which depend primarily on antenna design. If an antenna is wearable and implantable, the imaging system gives better results with less pain and cost. A wide band fabric antenna that operates at the ultra-wideband frequency with a low specific absorption rate (SAR) on breast phantom is verified. The proposed design has Jeans material as a substrate and the copper patch as a radiating element. The patch is designed in a circular shape with an M-type slot to suppress the spurious modes. The designed antenna model is commonly used for monitoring microwave imaging and has dimensions of 28X30X1.6 mm3. The proposed antenna design covers 2.3-8 GHz frequency with a broadside radiation pattern. The gain over the operating frequency is about 2.3-4.5 dB, and the efficiency is 55 %–79 %. The antenna model was designed and simulated in CST microwave studio. The performance of an antenna is tested on breast cancer to detect the presence of tumor cells in the breast. The antenna analysis on the phantom was done by considering the tumor location and corresponding results are presented. By varying the sizes of the tumor the antenna performance is analysed. The simulated SAR values of the proposed antenna design on breast phantom are under the limits of FCC.

Glasses frame‐based wearable antenna design for ultrahigh frequency radio frequency identification and Internet of Things applications using characteristic mode analysis

A novel ultra-high frequency (UHF) radio frequency identification (RFID) passive tag antenna based on a glasses frame is proposed for Internet of Things (IoT) applications. The glasses frame structure is exploited using characteristic mode analysis (CMA) to explore different modes for both 900 MHz and 2.4 GHz frequency bands. The proposed design consists of a glasses metallic frame and a loop for conjugate matching with an RFID chip (Alien Higgs H4). First of all, an already manufactured glasses metal frame structure is simulated in Computer Simulation Technology (CST) Microwave studio using CMA to get CM modes in the required RFID band. After that, a small loop is used along with the RFID chip as a capacitive coupling element to excite modes at 900 MHz by placing it at current minima. Moreover, the proposed tag antenna is also simulated with the voxel head model in CST and there is no significant change in impedance and reflection coefficient. The simulated specific absorption rate (SAR) is 0.5 W/Kg. Furthermore, the tag design is simulated with different glass materials and also with different frame structures to prove the robustness of the proposed solution. This tag design covers the entire US UHF RFID band (902–928 MHz) and features a read range of 2 m, measured using a UHF RFID reader setup with 4 W EIRP. Therefore, this antenna design can be a good candidate for future IoT technologies such as RFID, long range (LoRa), and other IoT applications.

Creation of a Rigorous Human Head Model from MRI Images with Reports on SAR Caused by 2.6 GHz 5G Mobile Handset Radiation

This research work proposes a method to rigorously model a 3D human head from the informative data in magnetic resonance imaging (MRI). The approach is based on each slice of 53 MRI resized to a 64 × 64 grayscale image to enable a practical simulation. The optimized unit cell of 5.6 × 5.6 × 5.6 mm3 is identified as a particular type of tissue. It corresponds to the average size of an actual human brain. The material properties are assigned to various tissues of the entire structure of the human head. The computational model of this will then be used as a virtual object to study the specific absorption rate (SAR) with electromagnetic radiation (EMR) at 2.6 GHz as a 5G mid-band frequency. A commonly known finite-different time-domain (FDTD) method is used as a tool in the SAR simulation. The key results show that a handset with a power of less than 0.8 W (Watts), operating at a handset to head separation distance of 1.12 cm, will meet the FCC SAR 1g limit of 1.6 W/kg.

In vitro detection of skin cancer using an UWB stacked micro strip patch antenna with microwave imaging

The inherent advantages of microwave imagining (MWI) being noninvasive and nonionizing for cancer detection, has attracted the attention of researchers in this area. Therefore, the present research article proposes an UWB (ultra-wideband) stacked MSA (Micro-strip antenna) for MWI of skin cancer. The proposed research work precisely focuses on the diagnosis of skin cancer in human forearm using the designed MSA in mono-static radar based configuration to collect S parameter data and process it to form an image of the scanned body area. The proposed UWB SAMPA (stacked aperture coupled micro-strip patch antenna) has three layered stacked aperture coupled geometry with a defected ground structure with dimensions 36 × 30 × 4.85 mm3. A simulated and measured bandwidth of 6.23 GHz (6.14 to 12.37 GHz) and 5.28 GHz (5.72 to 11 GHz) are observed and a gain of 6.3 and 6.4 dB is reported respectively. The in vitro detection of skin cancer is done by fabricating a bio mimic of human forearm with same electrical properties as that of human skin. The proposed SAMPA is used to collect S parameter data from the scan of forearm phantom. This data is then processed in beamforming algorithms to create a 2D dielectric profile of the scanned forearm area. The multiply Delay and Sum with Coherent factor (CF-DMAS) beam forming algorithm is utilized for reconstruction of the 2D image of the cancerous effected area along with its locations and size in MATLAB. The proposed MWI procedure is validated experimentally with the prototype of proposed SAMPA and a human forearm phantom after simulations in CST MWS. The proposed SAMPA is also safe for the human exposure, as it has simulated specific absorption rate (SAR) on the forearm phantom of 1.013 and 1.09 at frequency 7.04 and 8.67 GHz respectively.

Application of photogrammetry reconstruction for hyperthermia quality control measurements

PurposeHyperthermia is a cancer treatment in which the target region is heated to temperatures of 40–44 °C usually applying external electromagnetic field sources. The behavior of the hyperthermia applicators (antennas) in clinical practice should be periodically checked with phantom experiments to verify the applicator’s performance over time. The purpose of this study was to investigate the application of photogrammetry reconstructions of 3D applicator position in these quality control procedure measurements. MethodsPhotogrammetry reconstruction was applied at superficial hyperthermia scenario using the Lucite cone applicator (LCA) and phased-array heating in the head and neck region using the HYPERcollar3D. Wire-frame models of the entire measurement setups were created from multiple-view images and used for recreation of the setup inside 3D electromagnetic field simulation software. We evaluated applicator relation (Ra) between measured and simulated absolute specific absorption rate (SAR) for manually created and photogrammetry reconstructed simulation setups. ResultsWe found a displacement of 7.9 mm for the LCA and 8.2 mm for the HYPERcollar3D setups when comparing manually created and photogrammetry reconstructed applicator models placements. Ra improved from 1.24 to 1.18 for the LCA and from 1.17 to 1.07 for the HYPERcollar3D when using photogrammetry reconstructed simulation setups. ConclusionPhotogrammetry reconstruction technique holds promise to improve measurement setup reconstruction and agreement between measured and simulated absolute SAR.

Textile Bandwidth-Enhanced Coupled-Mode Substrate-Integrated Cavity Antenna with Slot

A textile bandwidth-enhanced coupled-mode substrate-integrated cavity antenna with a slot is presented. The original coupled-mode substrate-integrated cavity antenna is of two close resonances for the odd and even coupled modes, and a rectangular slot is added on the top layer to introduce a third resonance. Parameters are optimized to merge the bands of the three resonances to realize a widened −10 dB impedance band to cover the Medical Body Area Network band, 2.45 GHz Industrial Scientific Medical band and Long-Term Evolution Band7. The proposed antenna can operate in a −10 dB impedance band of 2.32–2.69 GHz with a 14.9% fractional bandwidth according to the measurements on a fabricated prototype. Simulation and measurement results illustrate the robustness of the proposed textile antenna in the vicinity of the human body and cylindrical bending conditions. In addition, the simulated specific absorption rate of the antenna radiation in the human body is lower than the IEEE and EN limits.

A miniature dielectric loaded wide band circularly polarized implantable antenna with low specific absorption rate for biomedical applications

An aperture coupled miniature dielectric loaded wide band circularly polarized implantable antenna is designed in this article. The antenna is proposed to operate in industrial, scientific, and medical band (2.4–2.48 GHz) for implantable biomedical applications. A square alumina ceramic dielectric material is used for miniaturization which leads to improvement of antenna bandwidth and gain. All the parameters of antenna are evaluated in a homogeneous cubic skin box and measured in saline solutions and minced pork both. The designed antenna has a simulated impedance bandwidth (|S11| < −10 dB) and axial ratio bandwidth <3 dB of 22% (2.21–2.75 GHz) and 7.36% (2.35–2.53 GHz), respectively and maximum −28.96 dBi peak gain observed at resonance frequency of 2.445 GHz. The proposed antenna confirms to the safety guidelines of IEEE standards of specific absorption rate (SAR). The simulated SAR is showing a low value of 11.64 W/kg average over 1 g tissue when input power is set to 1 W. Circular polarization, wide band, and very low SAR are the key features of the designed antenna. To validate the proper communication and data telemetry range with receiver antenna, link budget calculation has been done for designed antenna at 7 and 100 kbps data rates.

Personalized local SAR prediction for parallel transmit neuroimaging at 7T from a single T1-weighted dataset.

PurposeParallel RF transmission (PTx) is one of the key technologies enabling high quality imaging at ultra‐high fields (≥7T). Compliance with regulatory limits on the local specific absorption rate (SAR) typically involves over‐conservative safety margins to account for intersubject variability, which negatively affect the utilization of ultra‐high field MR. In this work, we present a method to generate a subject‐specific body model from a single T1‐weighted dataset for personalized local SAR prediction in PTx neuroimaging at 7T.MethodsMulti‐contrast data were acquired at 7T (N = 10) to establish ground truth segmentations in eight tissue types. A 2.5D convolutional neural network was trained using the T1‐weighted data as input in a leave‐one‐out cross‐validation study. The segmentation accuracy was evaluated through local SAR simulations in a quadrature birdcage as well as a PTx coil model.ResultsThe network‐generated segmentations reached Dice coefficients of 86.7% ± 6.7% (mean ± SD) and showed to successfully address the severe intensity bias and contrast variations typical to 7T. Errors in peak local SAR obtained were below 3.0% in the quadrature birdcage. Results obtained in the PTx configuration indicated that a safety margin of 6.3% ensures conservative local SAR estimates in 95% of the random RF shims, compared to an average overestimation of 34% in the generic “one‐size‐fits‐all” approach.ConclusionA subject‐specific body model can be automatically generated from a single T1‐weighted dataset by means of deep learning, providing the necessary inputs for accurate and personalized local SAR predictions in PTx neuroimaging at 7T.

Bandwidth-Enhanced Compact Circularly-Polarized Wearable Antenna With a Magneto-Electric Dipole

A compact broadband circularly-polarized wearable antenna is presented for wireless body area network (WBAN) off-body communications. The proposed antenna comprises two substrates, a semi-rigid substrate with low loss-tangent and a textile substrate, that can boost the antenna performance while maintaining wearer comfort. Initially, a crossed-dipole as a fundamental radiator that radiates a circularly polarized (CP) wave is printed on the semi-rigid substrate. A pair of L-shaped slits are loaded into crossed-dipole arm, which significantly miniaturizes the antenna size. A magneto-electric dipole as a parasitic element is loaded to widen axial ratio bandwidth (ARBW) and impedance bandwidth (IBW). A conductive textile is attached to the textile substrate as the ground plane to minimize the specific absorption rate (SAR). The simulated SAR at 5.85 GHz is below the US and EU limit standards. The proposed antenna has solved typical issues in wearable antenna design such as low gain, low radiation efficiency, large size, and narrow IBW and ARBW, while still providing comfortability to wearers.

Design and SAR assessment of three compact 5G antenna arrays

In this paper three different multi stub antenna arrays at 27–29.5 GHz are designed. The proposed antenna arrays consist of eight single elements. The structure of feeding parts is the same but the radiation elements are different. The feeding network for array is an eight way Wilkinson power divider (WPD). To guarantee the simulation results, one of the proposed structures is fabricated and measured (namely the characteristics of S11, E-, and H-plane patterns) which shows acceptable consistency with measurement results. The simulation results by CST and HFSS show reasonable agreement for reflection coefficient and radiation patterns in the E- and H- planes. The overall size of the proposed antenna in maximum case is 29.5 mm × 52 mm × 0.38 mm (2.8 {{varvec{lambda}}}_{0}× 4.86{{varvec{lambda}}}_{0} × 0.036{{varvec{lambda}}}_{0}). Moreover, for Specific Absorption Rate (SAR) estimation, a three-layer spherical human head model (skin, skull, and the brain) is placed next to the arrays as the exposure source. The simulation results show that the performance of proposed antennas as low-SAR sources makes them ideal candidates for the safe usage and lack of impact of millimeter waves (mmW) on the human health. In all three cases of SAR simulations the value of SAR1g and SAR10g are below the standard limitations.

Machine Learning-Based Prediction of MRI-Induced Power Absorption in the Tissue in Patients With Simplified Deep Brain Stimulation Lead Models

Interaction of an active electronic implant such as a deep brain stimulation (DBS) system and MRI RF fields can induce excessive tissue heating, limiting MRI accessibility. Efforts to quantify RF heating mostly rely on electromagnetic (EM) simulations to assess individualized specific absorption rate (SAR), but such simulations require extensive computational resources. Here, we investigate if a predictive model using machine learning (ML) can predict the local SAR in the tissue around tips of implanted leads from the distribution of the tangential component of the MRI incident electric field, Etan. A dataset of 260 unique patient-derived and artificial DBS lead trajectories was constructed, and the 1 g-averaged SAR, 1gSARmax, at the lead-tip during 1.5 T MRI was determined by EM simulations. Etan values along each lead's trajectory and the simulated SAR values were used to train and test the ML algorithm. The resulting predictions of the ML algorithm indicated that the distribution of Etan could effectively predict 1gSARmax at the DBS lead-tip (R = 0.82). Our results indicate that ML has the potential to provide a fast method for predicting MR-induced power absorption in the tissue around tips of implanted leads such as those in active electronic medical devices.

Inductive Power Transfer Link at 13.56 MHz for Leadless Cardiac Pacemakers

Inductive power links are most viable for the long-term powering of cardiac pacemakers. Designing an inductive power link without surpassing the specific absorption rate (SAR) for modern leadless cardiac pacemakers (LCPs) remains a challenging task because of its size and implantation depth. The inductive power link employed in the conventional works is either designed at a high frequency or based on the size, shape, weight, and implantation depth of conventional cardiac pacemakers. Here, a 3-coil inductive power transfer link with a circular transmitter coil and solenoidal receiver coil is designed at 13.56 MHz to provide uninterrupted power to the modern LCPs. Considering the food and drug administration approved term for implant size of modern LCP, the receiver coil is designed with 6 mm diameter and 6.5 mm length. The performance of the link has been verified through simulations and measurements under perfect alignment, lateral and/or angular misalignments, and distance variation between the coils. At a 50 mm horizontal distance between transmitter and receiver coils, the transmission coefficient is −30.9 dB. The maximum simulated average SAR at heterogeneous phantom is 0.30 W/kg, which is lower than the limit set by the Federal Communications Commission for radiation threshold exposure. Experiments conducted on pork’s heart verified the reliability of the simulated results. At a 50 mm distance between the coils, the measured transmission coefficient is −34 dB, and at an input power of 1 W, the power delivered to the load is 0.7 mW.

Design of a wide bandwidth and high gain wearable antenna based on nonuniform metasurface

AbstractA metasurface (MS) antenna for the 5 GHz wireless local area network (WLAN) band is presented in this paper. The antenna is feed by a modified aperture‐coupled structure with an optimized rectangular nonuniform MS to widen the bandwidth and improve the gain. The proposed antenna has a thickness of 4 mm and occupies an area of 50 mm × 50 mm. The operating frequency range of the antenna is 4.72–6.19 GHz, covering the 5.15–5.825 GHz band used by the 5 GHz WLAN. The measured average gain is 7.23 dBi. The simulated specific absorption rate values under 1 g and 10 g standard are lower than the limitation of U.S. and European. Due to its simple structure, wide bandwidth and small size, the proposed MS antenna has great potential in the wearable applications.

A compact dual-band semi-flexible antenna at 2.45 GHz and 5.8 GHz for wearable applications

In this work, a compact dual-band semi-flexible antenna operating at 2.45 GHz and 5.8 GHz for the industrial, scientific and medical (ISM) band is presented. The antenna is fabricated on a semi-flexible substrate material, Rogers Duroid RO3003™ with a low-profile feature with dimensions of 30×38 mm2 which makes it a good solution for wearable applications. Bending investigation is also performed over a vacuum cylinder and the diameters are varied at 50 mm, 80 mm and 100 mm, that represents the average human arm’s diameter. The bending investigation shows that reflection coefficients for all diameters are almost similar which imply that the antenna will operate at the dual-band resonant frequencies, even in bending condition. The simulated specific absorption rate (SAR) in CST MWS® software shows that the antenna obeys the FCC and ICNIRP guidelines for 1 mW of input power. The SAR limits at 2.45 GHz for 1 g of human tissue is simulated at 0.271 W/kg (FCC standard: 1.6 W/kg) while for 10 g is at 0.0551 W/kg (ICNIRP standard: 2 W/kg. On the other hand, the SAR limits at 5.8 GHz are computed at 0.202 W/kg for 1 g and 0.0532 W/kg for 10 g.