technique to reduce the specific absorption rate

Opt. In 2016 International Conference on Advances in Electrical, Electronic and Systems Engineering (ICAEES) 563566 (2016). The initial review displays that a powerful electric field distribution (EFD) that happened for nine resonance frequencies was displayed nearly the whole MSM design. A challenging problem that arises in this domain is how to decrease the SAR values at the desired resonance frequencies that comply with these guidelines. A vital discovery arises that the permittivity values of both substrate material and copper structures contribute significant advantages to gain distinct results. Although the proposed metamaterial designs in these earlier research works possess great properties, obtaining a left-handed behaviour at all resonance bands are remains limited. Commonly, the relationship between magnetic and electric responses is related to the physical characteristic of the electromagnetic field. & Cheng, Z. Terahertz perfect absorber based on InSb metasurface for both temperature and refractive index sensing. The defected ground structure technique and corrugations are used to increase the bandwidth and to reduce the specific absorption rate. The numerical simulations were comprised of three stages, namely MSM simulation, SAR reduction (in CST), and MSM simulation (in High-Frequency Structure Simulator 15.0 (HFSS)27). The preliminary analysis of this research work indicates that the bigger substrate materials can manifest lower resonance bands for the square-shaped metamaterial design. Overall, six distinct square-shaped metamaterials were constructed on 0.25mm thick Rogers RO3006 substrate material to reach the target of this investigation. Although, the SAR averaged over a 10g contiguous tissue region is essential in ICNIRP 1998, while the latest guidelines require it to be averaged over a 10g cubic region. Therefore, fulfilling the conflicting goals of lightweight design, lower bands with multi-frequency band operation, and high EM absorption values is a challenging task, requiring a unique and compact metamaterial design structure. A novel and effective technique to reduce electromagnetic - PubMed The retrieval equations of impedance (z), refractive index (n), permittivity (), and permeability () using the Robust method are defined in Eqs. Although previous studies regarding this issue possess substantial contributions in decreasing the SAR values discharged from mobile phones, the rising latest technologies require a progressive method or structure to better minimize the radiation effect. Google Scholar. At the L-band, the frequency ranges from 1.230 to 1.270GHz, 1.500 to 1.518GHz, and 1.596 to 1.692GHz have the negative permittivity behaviour with tolerable below-zero amplitude values of 63.019 to 4.294dB, 30.326 to 4.104dB, and 7.946 to 0.756dB, respectively. Commonly, the relationship between magnetic and electric responses is related to the physical characteristic of the electromagnetic field. The authors declare no competing interests. Cheng Y, Zou Y, Luo H, Chen F, Mao X. official website and that any information you provide is encrypted & Kwon, J. Specific absorption rate - Wikipedia For both tissue volumes, the metamaterial Positions 1 to 3 as in Fig. An investigation on specific absorption rate reduction materials with Finally, the obtained data accomplished the aim of this investigation where the SAR values of the proposed metamaterial structure reduced extraordinarily and have superior characteristics. The 5.872GHz resonance frequency has a higher MFD compared to the other resonance frequencies. Express 19(8), 69906998 (2011). At this frequency, the SAR reduction percentage value slightly increased in the 10mm distance. The performance of double-layer metamaterial structure was first investigated to identify whether the stacking affects the resonance frequencies. At the L-band, the frequency ranges from 1.230 to 1.270GHz, 1.500 to 1.518GHz, and 1.596 to 1.692GHz have the negative permittivity behaviour with tolerable below-zero amplitude values of 63.019 to 4.294dB, 30.326 to 4.104dB, and 7.946 to 0.756dB, respectively. SAR reduction values for 1g of tissue volumes at various metamaterial positions. Evaluation and Optimization of the Specific Absorption Rate for and transmitted securely. The proposed compact metamaterial design helps to reduce the Specific Absorption Rate (SAR) value that exposed to the human head. 16, 839847 (2020). Besides that, the proposed metamaterial is suitable for EM absorption reduction applications. The main disadvantage is some smearing of the slice profile that can lead to spatial blurring in the image. In. The preliminary outcome of this research work indicates that the multi-layered metamaterial structure has a great influence on the SAR reduction values. These square-shaped rings were built accordingly to obtain multi resonance frequencies. Saturation pulses of all types. A similar simulation method as in the CST software was adopted for this simulation process. The two-layered homogenous metamaterial structure exhibit nine resonance frequencies which are similar to the proposed MSM design, but has lower magnitude values at certain peak points. Furthermore, we discovered that the SAR values averaged over 1g and 10g of tissue volume reduced in a similar pattern and has a reduction percentage mean value of 88.931% and 88.828%, respectively. Concern about RF exposure to humans increases tremendously because of the fast growth in the usage of mobile phones. Usually, most materials fall under two classifications, for instance, dispersive and lossy materials. In addition, the introduced MSM structure manifests left-handed behaviour at all the resonance frequencies. 8d was selected because it manifested optimised SAR values. Described below is a simple method for the attachment by physical adsorption of avidin, streptavidin, BSA, other proteins or antibodies to IDC UltraClean latex beads. Ramachandran T, Faruque MRI, Ahamed E. Composite circular split ring resonator (CSRR)-based left-handed metamaterial for C- and Ku-band application. Therefore, in this research work, the author focused only on the metamaterial structure that can be integrated inside the mobile phone without disturbing any existing parts. The stated latest research works have shown that, although the proposed scope of applications is varied for each other, the distinctive qualities of metamaterial allow the researchers to gain extraordinary outcomes. The parametric studies in this section were focused on different positions of metamaterial inside the mobile phone, the various distances between mobile phone to the voxel human head, and radiation reduction using unit cell metamaterial. Dielectric properties of the phone material and SAM phantom. The simulation results of the unit cell metamaterial were further validated by the equivalent circuit model. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The second part focuses on strategies to efficiently reduce adsorption at components of the autosampler, column and mass spectrometer. 2a. Metamaterial techniques seem promising options to reduce the SAR in terms of low cost and ease-of implementation in mobile phones. Therefore, fulfilling the conflicting goals of lightweight design, lower bands with multi-frequency band operation, and high EM absorption values is a challenging task, requiring a unique and compact metamaterial design structure. For the electromagnetic absorption reduction application, the authors successfully introduced a shielding material to absorb radiation from the wireless device. 7c possesses capacitive effects (C1 to C20) are denoted for the gaps between rings, while the inductive effect (L1 to L41) is for metallic strips. S21 results of: (a) Unit cell MSM design, (b) Several substrate materials analyses for proposed MSM design, (c) Equivalent circuit. Therefore, the distance between the antenna and the human head model was roughly 20mm. Phi and theta of 0 to 45: (a) S11 Polarization, (b) S21 Polarization, (c) S11 Incident angle, (d) incident angle. MSM structure mostly was positioned all over the phone to find the variation in SAR reduction values. The simulation of the proposed metamaterial was carried out by adopting commercially available software known as Computer Simulation Technology (CST) Microwave Studio 201926. The second to fifth square rings have widths of 0.80, 0.20, 0.40, and 0.40mm, respectively. The studies on satellite application4,5 also become a hot topic in the scientific community. February 3, 2021 | American Journal of Roentgenology, Vol. The fundamental theory of the left-handed behaviour defined, besides the refractive index possesses negative amplitude values, the permittivity and permeability values as well have the same performance. Specific absorption rate analysis of broadband mobile antenna with In the S-band, negative permeability values were observed from 2.004 to 3.222GHz and 3.636 to 3.996GHz with the amplitude values moderately changed between 34.455 to 4.384dB and 20.900 to 14.318dB. In conclusion, the proposed MSM met the objectives of this research study and can be employed in EM absorption reduction applications. The centre point of the antenna structure in the mobile phone was aligned along the central right cheek area. [2] introduced a new triangular-shaped metamaterial for electromagnetic (EM) absorption reduction. In this section, using an imported cell phone model from CST, the simulation was done while operating at the highest power level for all the resonance frequencies. Appl. The MSM design possesses an optimised EMR value at 1.200GHz, which was decreased for the following resonance frequencies. The SAR exposure value of the mobile phone with and without the MSM attachment was calculated using a time-domain solver. All the frequency ranges of the left-handed characteristic are tabulated in Table 3. Article Therefore, the multi-layered metamaterial structure was introduced in this research work. The specific absorption rate (SAR) value measures the rate at which radiation is absorbed by the human body when exposed to radio waves. On the other hand, the following bands have two negative characteristics for each, respectively. 3a. Table 4 demonstrates the EMR values for all resonance frequencies. The impedance value achieved a peak value in the L-band, for instance, 1.863, 0.720, 3.361 at 1.272,1.524, and 1.692GHz, respectively. Meanwhile, Fig. Meanwhile, the SAR values averaged over 1g and 10g of tissue volumes, calculated using the CST software, with and without the metamaterial structure at all nine resonance frequencies which fall in the L-, S- and C-bands are tabulated in Tables 5 and 6. Commonly, this type of metamaterial is composed of multi altering layers of substrate materials that are used in a wide range of applications such as sensors, absorption, perfect imaging, coatings for tailored emittance, etc. A material that has an extraordinary and superior accomplishment, referred to as a metamaterial, is responsible for the debate topic of conversation in the telecommunications field. 127, 214902. https://doi.org/10.1063/5.0002931 (2020). & Islam, M.T. Meanwhile, this numerical simulation data reveals acceptable magnitude values such as 25.208, 26.243, 22.194, 30.951, 23.203, 14.263, 24.422, 24.636, and 23.916dB. The unit cell metamaterial was simulated in CST software with a similar method as described in the computer simulation technique section. A multi-band closed-cell metamaterial absorber (CCMA) based on a low-permittivity all-dielectric structure. September 10 . 4. One of the most commonly used methods is the metamaterial structure where it will generally block or absorb the radiofrequency energy from entering the human body. Cheng, Y., Zou, Y., Luo, H., Chen, F. & Mao, X. The comparison of both simulation and measurement methods indicates a slight difference in the fourth resonance, while on the fifth peak point, the results majorly differ. Besides unique electromagnetic properties, unconventional material provides additional benefits likely, good elasticity, strength, or heat conduction. 6ad. A rectangular bar with a length and width of 5mm and 0.60mm was added after a gap of 0.40mm from the last ring. In general, these materials exhibit superior permittivity, permeability values and as well finest resonance frequencies. Both analyses indicate that the variations in angle have a major influence on the outcomes and manifest dependent characteristics. Besides that, the MSM design is small, unintentional flaws might have happened when removing excess copper from the substrate material. A Review: Methods to Lower Specific Absorption Rate for Mobile Phones 2c. Authors The physical and effective medium properties of the proposed MSM design are the main factors to utilise in a wide range of applications. . Fu, P. et al. This unconventional material is unable to find in a natural state and possesses unique effective medium parameters which are also difficult to gain in conventional materials3. Before measurement was carried, the VNA instrument was calibrated by using the Agilent N4694-60001 device. volume12, Articlenumber:1803 (2022) The SAR exposure value of the mobile phone with and without the MSM attachment was calculated using a time-domain solver. The specific absorption rate (SAR) reduction technique is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. 29(4), 514524 (2015). 5. Purpose: To improve image quality and reduce specific absorption rate in functional cardiac imaging at 3 T. Methods: Two high permittivity dielectric pads on the anterior and posterior sides of the thorax were numerically designed and implemented using an aqueous suspension of barium titanate. Results Phys. Int. The preliminary outcome of this research work indicates that the multi-layered metamaterial structure has a great influence on the SAR reduction values. The polarization-dependent values exhibit 25% discrepancies when compared to the proposed metamaterial S21 result. proposed a circular-shaped split ring resonator on an FR-4 substrate material of 1.60mm thickness. 7a. Passive Adsorption Protocol | Thermo Fisher Scientific - US Han, N. R., Chen, Z. C., Lim, C. S., Ng, B. Therefore, with a gap of 0.70mm, the last ring was built with a width of 0.50mm. Minimum SAR VERSE pulses are typically somewhat flat in their central region and amplified toward their periphery. A specific absorption rate reduction method for simultaneous - PubMed For the validation purpose, the fabricated unit cell metamaterial was undergone a measurement process by utilising Agilent N5227A Vector Network Analyser (VNA) as demonstrated in Fig. 7a. In these studies, the metamaterial design has satisfactory absorption reduction values, but we aimed to obtain resonance frequencies more than dual-band.
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