A low-profile circularly polarized patch antenna with wide axial ratio bandwidth

Abstract This paper proposes a circular-shaped patch antenna with wide circularly polarized bandwidth (CPBW). A circular-shaped patch has been designed on a low loss substrate having a complete ground. A pair of parallel slots with different lengths is etched on the patch to achieve wider CPBW. These offset-based parallel slots are incorporated purposefully to redistribute the electric fields on the patch surface, which tunes the two orthogonal far field components across a wide frequency range and controls axial ratio (AR) of the CP antenna. The gap between the parallel slots plays an important role for tuning the electric field distributions. The measured results of the proposed antenna provide the impedance bandwidth (≤−10 dB) (IBW) of 27.11% (5.1–6.70 GHz) , CPBW (AR ≤ 3 dB) of 36.22% (5.2–7.5 GHz) and realizes its effective overlapping CPBW of 25.21% (5.2–6.7 GHz). A left-handed circular polarization (LHCP) radiation with a peak gain of 6.7 dBic has been achieved across the CP band. A good agreement is observed between the simulation and measured results.