Circularly Polarized Antipodal Curvedly Tapered Slot Antenna with Circular Radiation Pattern

The aperture field and radiation characteristics of the wideband circularly polarized (CP) antipodal curvedly tapered slot antenna (ACTSA) is proposed in this paper. The simulated radiation characteristics is in agreement with the measurement, the small simulated differences (less than 7.2°) of the half power beam width (HPBW) between x-z and y-z plane are achieved from 50 to 75 GHz and the measured one are less than 4° at 50, 69 and 75 GHz. The measured results show that the antenna can achieve a 40% bandwidth for both axial ratio (AR) <3 dB and $\vert \mathrm{S}_{11}\vert \lt -10$ dB from 50 GHz to 75 GHz.