Near-Field WPT using Defected Ground Structures for UHF RFID Applications

Abstract

Wireless Power Transfer (WPT) has gained importance in the 21st century for its potential applications in Radio Frequency Identification (RFID), and Internet of Things (IoT) based wireless sensors. This technology removes the need for batteries on the RFID tag, thereby increasing its shelf life and reducing its cost. There are mainly two types of wireless power transfer-near-field $(\approx$ mm, cm) and far-field $(\approx$ km). In this work, a compact H-shaped Defected Ground Structure (DGS) has been used to design a notch filter and a WPT system for Ultra-High Frequency (UHF) RFID applications(860-960 MHz). The WPT efficiency of the proposed design is 70 % over a distance of 8 mm and resonates at 880 MHz. The DGS has been designed using CST Microwave Studio and fabricated on an FR-4 PCB making for a compact design for applications in passive RFID systems.