A low-profile CPW-fed broadband antenna for WLAN and RFID applications

This paper presents a novel compact broadband circularly polarized slot antenna fed by a co-planar waveguide (CPW), suitable for use in WLAN and RFID applications. The antenna is only 20 × 24 mm in size. Measured impedance bandwidth (VSWR < 2) at center frequency of 5.8 GHz is 24% and the 3 dB axial-ratio (AR) bandwidth is 3.1%. The antenna has an omnidirectional radiation pattern with a maximum gain of −0.5 dB.