Ramachandran Tayaallen, Faruque Mohammad Rashed Iqbal, Siddiky Air Mohammad, Islam Mohammad Tariqul
Space Science Center (ANGKASA), Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
Sci Rep. 2021 Jan 29;11(1):2619. doi: 10.1038/s41598-021-82105-7.
This study aims to demonstrate the feasibility of metamaterial application in absorption reduction of 5G electromagnetic (EM) energy in the human head tissue. In a general sense, the radio frequency (RF) energy that received by wireless mobile phone from the base station, will emit to surrounding when the devices are in active mode. Since the latest fifth generation technology standard for cellular networks is upon us, the emission of radiation from any wireless devices needs to be taken into consideration. This motivation helps to prepare this paper that focuses on construction of novel and compact square-shaped metamaterial (SM) design to reduce electromagnetic exposure to humans. The commercially available substrate material known as FR-4 with thickness of 1.6 mm was selected to place the metamaterial design on it. The electromagnetic properties and Specific Absorption Rate (SAR) analyses were carried out numerically by utilising high-performance 3D EM analysis, Computer Simulation Technology Studio (CST) software. Meanwhile, for the validation purpose, the metamaterial designs for both unit and array cells were fabricated to measure the electromagnetic properties of the material. From the numerical simulation, the introduced SM design manifested quadruple resonance frequencies in multi bands precisely at 1.246 (at L-band), 3.052, 3.794 (at S-band), and 4.858 (C-band) GHz. However, the comparison of numerically simulated and measured data reveals a slight difference between them where only the second resonance frequency was decreased by 0.009 GHz while other frequencies were increased by 0.002, 0.045, and 0.117 GHz in sequential order. Moreover, the SAR analysis recorded high values at 3.794 GHz with 61.16% and 70.33% for 1 g and 10 g of tissue volumes, respectively. Overall, our results demonstrate strong SAR reduction effects, and the proposed SM design may be considered a promising aspect in the telecommunication field.
本研究旨在证明超材料应用于减少人体头部组织中5G电磁（EM）能量吸收的可行性。一般来说，无线移动电话从基站接收的射频（RF）能量，在设备处于活动模式时会向周围环境发射。由于最新的蜂窝网络第五代技术标准即将到来，任何无线设备的辐射发射都需要考虑。这种动机促使撰写本文，重点是构建新颖紧凑的方形超材料（SM）设计，以减少对人体的电磁暴露。选择厚度为1.6毫米的市售基板材料FR-4来放置超材料设计。利用高性能3D电磁分析软件计算机模拟技术工作室（CST）对电磁特性和比吸收率（SAR）进行了数值分析。同时，为了进行验证，制作了单元和阵列单元的超材料设计，以测量材料的电磁特性。从数值模拟结果来看，引入的SM设计在多频段精确地表现出四个共振频率，分别为1.246（L波段）、3.052、3.794（S波段）和4.858（C波段）GHz。然而，数值模拟数据与测量数据的比较显示，两者之间存在细微差异，其中只有第二个共振频率降低了0.009 GHz，而其他频率依次增加了0.002、0.045和0.117 GHz。此外，SAR分析在3.794 GHz时记录到较高的值，对于1克和10克组织体积，分别为61.16%和70.33%。总体而言，我们的结果表明有很强的SAR降低效果，所提出的SM设计可能被认为是电信领域一个有前景的方面。
