CPW-fed slot antenna with fractal tuning stub for wideband circular polarization

Based on the use of the fractal tuning stub and slot radiator, a wideband circularly polarized coplanar waveguide (CPW)-fed slot antenna with fractal tuning stub is presented. The fractal tuning stub has been designed to enhance widely the impedance bandwidth. Moreover, in order to achieve the extended axial ratio bandwidth, the slot radiator is etched and verified on the upper slot. The proposed antenna attains an overlapped bandwidth (axial ration ≤ 3 dB and return loss ≤ 10 dB) of 45% (2.25-3.57 GHz) in measurement.