Enhancement of radio frequency energy harvesting using embroidery conductive thread and improved power management circuit design

The global demand for remotely powering electronic devices without batteries, particularly for low-power electronics, through ambient RF (Radio Frequency) energy harvesting is increasing. However, several challenges must be addressed for Radio Frequency energy harvesting to achieve its full potential in wearable technology. These challenges include: 1. Maintaining continuous and steady conductivity of the antenna patch in RF energy harvesting (RFEH) devices. 2. Enhancing the efficiency of current rectification and power management circuits at extremely low power levels. This PhD project aims to overcome these obstacles by employing innovative embroidery conductive thread technology, which offers more uniform conductivity compared to traditional ink-based fabrication techniques. Additionally, the project focuses on designing an improved rectifier for the power management circuit. The proposed rectenna patch antenna is based on a 50-ohm impedance matching network. The design, simulation, optimization, and efficiency results of the rectenna patch antenna were recorded. The fabrication involved creating an efficient patch on both a textile substrate using conductive threads and a plastic substrate using liquid metal alloys. An embroidery machine was used for the textile design, while an inkjet printer was utilized for the plastic substrate. The harvested energy results were documented, demonstrating an improvement in the current wearable RF power harvesting system. This study provides valuable insights into materials, antenna design, and power management systems, advancing the state-of-the-art in RF energy harvesting and paving the way for further research and development.