Circularly polarized metamaterial Antenna in energy harvesting wearable communication systems

Computer Science and Information Technologies Vol. 4, No. 2, July 2023, pp. 106~118 ISSN: 2722-3221, DOI: 10.11591/csit.v4i2.pp106-118  106 Circularly polarized metamaterial Antenna in energy harvesting wearable communication systems Bala Inuwa1, Olabode Idowu-Bismark2, Oluseun Oyeleke1, Jemitola Paul olugbeji3 1 Department of Computer Engineering, Nile University of Nigeria, Abuja, Nigeria Department of Electrical and Information Engineering, Covenant University, Ota, Nigeria 3 Department of Electrical and Electronic Engineering, Nigerian Airforce institute of Technology, Kaduna 2 Article Info ABSTRACT Article history: When battery powered sensors are spread out in places that are sometimes hard to reach, sustaining them become difficult. Therefore, to develop this technology on a large scale such as in the internet of things (IoT) scenario, it is necessary to figure out how to power them. The proffered solution in this work, is to get energy from the environment using energy harvesting Antennas. This work presents a wearable circular polarized efficient receiving and transmitting sensors for medical, IoT, and communication systems at the frequency range of WLAN, and GSM from 900 MHz up to 6 GHz. Using a cascaded system block of a circularly polarized Antenna, a rectifier and t-matching network, the design was successfully simulated. A DC charging voltage of 2.8V was achieved to power-up batteries of the wearable and IoT sensors. The major contribution of this work is the tri-band Antenna system which is able to harvest reflected Wi-Fi frequencies and also GSM frequencies combined in a miniaturized manner. This innovative configuration is a step forward in building devices with over 80% duty cycle. Received Dec 13, 2022 Revised May 28, 2023 Accepted Jun 7, 2023 Keywords: Circularly polarized antenna Green energy source Metamaterials antenna Radio frequency energy harvesting module Wireless sensors This is an open access article under the CC BY-SA license. Corresponding Author: Olabode Idowu-Bismark Department of Electrical and Information Engineering, Covenant University Canaan Land Ota, Nigeria Email: 1. INTRODUCTION Commercially available wireless sensors in the communication industry are battery powered with limited lifespan to a certain number of cycles. It is difficult to maintain such sensors in remote locations. With the boom in the internet of things (IoT) it then become necessary to find solutions for energy supplies to the billions of such remotely located sensors. Energy harvesting Antennas comes as viable solution to providing such energy which will eliminate the necessity for maintaining or replacing batteries for those sensors, thereby increasing the sensors lifetime. Wireless sensors are used for body implant in the medical field as well as industrial sensors for industrial automation [1], [2]. In the medical field, this will optimize the use of wearable technologies. One of the upcoming technologies that can help solve the above power feeding problem is radio frequency (RF) energy harvesting [3]. Energy harvesting devices offer renewable energy and may remove the need for daily battery replacements. It is critical to collect electromagnetic power for a wide range of wireless communication systems to utilise as such free space energy is feasible. In these instances, ultra-wideband Antennas should be used [4], [5]. A programmable array with multiple Antennas can harvest energy from 100 MHz to 18 GHz. Figure 1 shows energy harvesting resources versus requirement. Journal homepage: http://iaesprime.com/index.php/csit Comput Sci Inf Technol ISSN: 2722-3221  107 Figure 1. Energy harvesting As a result of low-power electromagnetic energy densities in free space, it is necessary that energy harvesting Antenna meet certain requirements which include high efficiency, definite frequency operation range and polarization. Also, a wide beam or omni-directional radiation pattern is required for the Antenna [2]. Wideband printed compact slot and notch Antennas are excellent in their application for wideband energy harvesting systems as they are compact, low cost, flexible, and efficient. The electronic devices that are used in our daily lives have undergone significant changes over the past several decades along with the advancement of sensor technologies. Many strategies for generating electricity from these many sources of energy have been researched and developed [1], [2]. It is crucial to harvest the electromagnetic energy for a wide range of wireless communication systems in order to utilize the maximum amount of free space energy. For energy collecting applications, several printed Antennas have been used [6]. In communication and medical systems, patch and slot Antennas are frequently employed, wideband printed small slot and notch Antennas became excellent solutions for wideband energy harvesting devices. The system RF components and the Antennas can also be integrated on the same substrate to create a small, low-cost energy harvesting network and matching network [7]. In this study, high efficiency circular polarized Antennas with energy collecting units are designed for communication, IoT applications, 5G applications, and healthcare sensors. In circular polarization, the electric field of the light contains two linear components that are perpendicular to one another, equal in amplitude, but differ by a phase of Π/2. This is known as circular polarization. The plane of polarization revolves in a corkscrew pattern, producing one full rotation for each wavelength in a circularly polarized Antenna. Energy is emitted by a circularly polarized wave in all planes, including the horizontal, the vertical, and any plane in between [8]. Right-hand circular (RHC) is the sense when the rotation is clockwise and looking in the direction of propagation. Left-hand circular (LHC) is the term for the feeling when the rotation is counter clockwise. Figure 2 shows the circular polarization pattern. Figure 2. Circular polarization pattern For 5G, IoT, and healthcare applications, wearable circular polarized patch Antennas with concentric complementary split ring resonators (CSRRs) were created [9], [10]. The new sensors' bandwidth ranges from 10% to 20% for voltage standing wave ratio (VSWR) better than 3:1. The Antennas with CSRRs have a gain of about 8 dB. The sensor's effectiveness is greater than 90%. Self-powered, effective, and small sensors are provided by the energy harvesting modules coupled to the sensors. Table 1 compares research on power-harvesting Antennas that has been published. The core concept of metamaterial design is to craft materials by using artificially designed and fabricated structural units to achieve the desired properties and functionalities. The use of metamaterials in Antenna design greatly reduce the size of the Antenna and also improve the Antenna characteristics, such as enhancing bandwidth, increasing gain, and helping (...truncated)