Investigation of Broadband Circularly-Polarized Unbalanced Dipole Antenna Consisting of Semicircular and Trapezoidal Elements

In this paper, a circularly-polarized antenna operating in a broadband has been studied by modifying the shape of the unbalanced dipole antenna consisting of semicircular and trapezoidal elements, well-known to have broadband characteristics. As a result, it was confirmed that the antenna studied in this paper operated with S
₁₁
<; -9.8 dB and axial ratio <; 3 dB over a broadband of 3.85 to 6.3 GHz.