A compact broadband microstrip slot circularly polarized antenna using parasitic elements

ABSTRACT A new broadband circularly polarized (CP) microstrip slot antenna (MSA) is proposed in this study. The proposed CP MSA is comprised of a square-loop feed configuration, four rectangular patches as parasitic patches, and a square ground plane etched with four L-shaped slots as parasitic slots. The square-loop feed configuration, which can stimulate a 270° phase difference, comprises an arc-shaped strip and a square-loop. Rectangular patches and L-shaped slots as parasitic elements are together arranged and etched at the side of the square-loop feed configuration to excite multiple CP resonant modes using a capacitively coupled feeding technology. A prototype of the proposed antenna was simulated, manufactured, and measured in this study. The measured results depict that the CP MSA features a wide impedance bandwidth of 4.36–5.36 GHz (20.6%) for|S11| < −10 dB and broad axial ratio bandwidth (ARBW) of 4.53–5.30 GHz (15.7%) for AR < 3 dB. Thus, the proposed CP MSA would be an outstanding candidate in wireless communication systems.