Circularly Polarised RFID Reader Antenna with an Integrated Power Divider

In modern times, Ultra High Frequency (UHF) Radio Frequency Identification (RFID) systems have been widely utilized for tracking across various applications, including human surveillance, healthcare, library management, inventory control and the Internet of Things (IoT). Various antennas have been developed for RFID applications in previous studies; however, they come with certain limitations. Some exhibit a lower bandwidth percentage, while others have reduced gain. To address these issues, this paper proposes an RFID reader antenna with enhanced gain. The proposed RFID antenna operates within the 846 - 950 MHz frequency band, offering a 11.58 % bandwidth and a gain of 9.05 dBi. Additionally, it possesses 1.2 dB axial ratio and is circularly polarised. The antenna design includes an aluminium ground measuring 296 mm x 296 mm x 1.6 mm and a stainless steel patch with 165 mm x 146 mm x 0.8 mm dimensions. The designed antenna is analysed through simulations using Ansys High Frequency Structure Simulator (HFSS).