Design of 24–40 GHz Ultra-Wideband Circularly Polarized Monopole Antenna with a Defected Ground Plane

A new design method for an ultra-wideband circularly polarized microstrip-fed monopole antenna with a ground defect is proposed in this paper. To achieve circular polarization performance, parallelogram-shaped employed the bottom layer. The analysis of axial ratio (AR) and impedance bandwidth performed both top layers. semi-circular aperture designed to matching 24–40 GHz frequency range. Then, AR discussed considering surface current distribution produced by rote each orthogonal phase. prototype 50% ultra-wide (from 24 40 GHz), 10-dB return loss, 3-dB was fabricated measured. 6-dBic right-hand gain also achieved.