Novel concentric hexagonal-shaped RFID tag antenna with T-shaped stub matching
This paper presents a unique concentric hexagonal-shaped ring antenna for radio frequency identification (RFID) tags. The rings are excited with a common microstrip feedline. The radiation characteristics of the antenna is improved by locating a horizontal a parasitic element in the vicinity of the hexagonal-shaped rings. The proposed antenna was used in the implementation of a 3×1 antenna array. The impedance match of the 3×1 RFID tag was enhanced by incorporating a T-shaped stub. The antenna is designed to operate at the UHF band from 800 MHz to 960 MHz. It was implemented on FR-4 substrate with dielectric constant and thickness of 4.3 and 1.6 mm, respectively. The size of the RFID tag antenna is 36×10 mm 2 . Its impedance was matched to Alien Higgs RFIC chip of impedance 10 – j 82.5 Ω at 895 MHz. Measured results show the proposed RFID tag antenna provides an impedance bandwidth, maximum gain and radiation efficiency of 160 MHz, 2 dBi, and 66.5%, respectively. With effective isotropic radiated power (EIRP) limited to 36 dBm to comply with FCC regulations for UHF band RFIDs it radiates in the broadside direction over a range of 9 m making it desirable for various applications including supply chain management, logistic control, and vehicle identification. ; This project has received funding from Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant 801538. Also, this work is partially supported by RTI2018-095499-B-C31, Funded by Ministerio de Ciencia,Innovación y Universidades, Gobierno de España (MCIU/AEI/FEDER,UE). Additionally, it received funding from the Researchers Supporting Project number (RSP-2021/58), King Saud University, Riyadh, Saudi Arabia.