Energy Harvesting From 5G Using Reshaped Grid Antenna Arrays

Abstract

The Internet of Things (IoT) connects physical devices, vehicles, household appliances, and other objects through embedded electronics, software, sensors, actuators, and network connectivity, enabling them to communicate and exchange data. This interconnected ecosystem has revolutionized industries ranging from smart homes and wearable technology to healthcare and manufacturing. However, the rapid expansion of IoT devices has introduced significant challenges, particularly in terms of energy consumption. To address this issue, energy harvesting systems have been explored as a viable solution. These systems capture ambient energy from sources such as solar, thermal, vibrational, and radio frequency (RF) environments to power IoT devices sustainably. This thesis focuses on harnessing the high data transfer capabilities of 5G mm-wave networks to optimize energy harvesting for IoT applications. A redesigned grid antenna array was developed, leading to a new antenna theory aimed at enhancing both performance and energy harvesting efficiency. A circularly polarized grid array antenna was designed, achieving a gain of 13.8 dBic across a broad frequency range (28.4–33.4 GHz). To further improve efficiency, a new approach called "Octa Sequential Rotation" was proposed. Unlike traditional sequential rotation methods, this technique uses only eight antennas instead of sixteen, resulting in better gain performance and a more compact design. The implementation of this approach requires an 8-port feeding network, offering significant advantages over conventional designs, which typically require five separate 4-port networks. In addition, a high-efficiency rectifier was designed to complement the antenna system. Operating between 28 GHz and 33 GHz, the rectifier achieves an efficiency of 30% at an input power of 20 dBm. It plays a crucial role in converting captured RF energy into usable DC power, enhancing the overall effectiveness of the energy harvesting system. By combining circularly polarized antenna design, 5G network utilization, and efficient RF-to-DC conversion, this thesis offers a promising solution to the energy challenges faced by IoT devices. The developed system lays the groundwork for more sustainable and autonomous IoT ecosystems.