A compact wideband slot antenna for universal UHF RFID reader

Abstract

In this letter, a new wideband circularly polarized antenna for Radio Frequency Identification (RFID) readers is proposed. A prototype operating in the Ultra-High Frequency (UHF) band is successfully realized and tested using a defected Ground Structure (DGS). This antenna consists of an L-shaped metal strip and a DGS with four tuning stubs. The overall size covers 90 ∗ 90 ∗ 1.6 mm3. The measured −10 dB reflection coefficient S11 bandwidth is 27% (800–1020 MHz), and a good radiation pattern and suitable gain coefficient about 3.7 dB have been achieved. Also, an excellent agreement was noticed between simulation and measurement results demonstrating the good performance of the proposed antenna.