CPW-fed sqaure ring slot antenna with circular polarization radiation for WiMAX/WLAN applications.

ABSTRACT The design of a small size 50 × 50 mm2 coplanar waveguide-fed square ring slot antenna is studied. To attain circular polarization (CP) radiation with broad 3-dB axial ratio (AR) bandwidth that can cover the worldwide interoperability for microwave access 2.3 GHz (2305-2320 MHz, 2345-2360 MHz) and wireless local area network 2.4 GHz (2400-2480 MHz) bands, a novel technique of extending a C-shaped branch from the vertical monopole is proposed. Good impedance matching and CP performance was achieved by further extending a vertical tuning strip from the C-shaped branch. From the measured results, 10-dB impedance bandwidth and 3-dB AR bandwidth of 63.89% and 7.93% were achieved. Furthermore, stable gain variation of approximately 2.7 dBic and radiation efficiency of more than 85% were also exhibited across the bands of interest. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:886-891, 2015 [ABSTRACT FROM AUTHOR]