A Novel Circularly Polarized Antenna with Enhanced Axial-Ratio Bandwidth for Millimeter-wave Application

A wideband circularly polarized (CP) antenna is proposed for millimeter-wave applications. The basic unit of the array is a novel CP ME-dipole. A differential feeding network composed of SICL is utilized for symmetric radiation pattern of the antenna. A new transition between SICL and rectangular waveguide is also designed for the feeding network. The simulated impedance bandwidth (|S
₁₁
| ≤ 15 dB) and 3-dB axial ratio (AR) bandwidth of the antenna array are 16.5% and 15%, respectively. Besides, the simulated gain of the antenna array is around 12.5 dBi over the operating band.