Wideband circularly polarised planar monopole antenna array

A simple design for a wideband circularly polarised planar monopole antenna array is presented. The attractive characteristics of the proposed antenna array are the wide impedance bandwidth of 87.3% (1 to 2.55 GHz), the 3 dB axial ratio (AR) bandwidth of 95% (1.05 to 2.95 GHz), and the maximum gain within the 3 dB AR bandwidth of about 4 dBi.