BROADBAND CIRCULARLY POLARIZED ANTENNA WITH HIGH GAIN AND WIDE AXIAL RATIO BEAMWIDTH

A broadband circularly polarized (CP) antenna with simple structure and wide angular coverage is proposed. The interlaced coplanar dipole is excited by a coaxial cable to achieve the CP wave. To obtain a high gain and low backward radiation, a rectangular cavity-backed reflector is used. An initial design at around 6.0 GHz is presented to show the performance of this configuration. An impedance bandwidth and axial ratio bandwidth of about 35.6 and 33.5% can be achieved at this frequency. Also, a stable gain of about 10 +/- 0.5 dBi and a wide axial ratio beamwidth of about 200 degrees over the frequency of interest are obtained. Then, a parametric analysis is conducted to estimate the significance of the design parameters that affect the antenna's performance. Finally, a prototype at 11.0 GHz is fabricated to validate the design. The measured results are in good agreement with the simulated ones, which shows that the design can be easily applied to other frequency and that the design may be a good candidate for the CP antenna family. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:377-381, 2015