Square Slot Antenna for Wide Circularly Polarized Bandwidth and Axial Ratio Beamwidth

摘要

The article proposes design investigation andexperimental results of a coplanar waveguide (CPW) fed squareslot antenna that gives wideband circular polarization. Thiscircular polarization characteristic is achieved by embedding asquare shape stub to left bottom corner and an L-shaped strip tothe right upper corner of the slot. A high impedance bandwidth of87.8 % (3.6–9.0 GHz), a wide axial ratio bandwidth of 73.05 %(4.2–9.0 GHz) and wide 3-dB axial ratio beamwidth of 90° in theentire frequency range of interest are achieved with this antennastructure. To improve the 3-dB axial ratio bandwidth, threeslots (two horizontal and one vertical) are scratched at the exteriorperiphery of the ground plane. These perturbation assemblies areaccountable to excite orthogonal modes and help increase an axialratio bandwidth. The designed antenna displays the constant andsteady radiation patterns in the complete frequency range ofconcern. The overall dimension of the presented compact antennais 0.24λ × 0.24λ × 0.01λ.