Omnidirectional Circularly Polarized Antenna with Wide Bandwidth and Axial-Ratio Beamwidth Using Conformal Dielectric Polarizer

An omnidirectional circularly polarized (CP) antenna with wide bandwidth and axial-ratio (AR) beamwidth is proposed for millimeter-wave applications. The wideband (WB) and wide AR beamwidth (ARBW) performance is realized by a novel conformal dielectric polarizer design. Each curved slab of the polarizer is conformally tilted 45° to the incident electric field of the linearly polarized (LP) spherical wavefront. Apart from the conformal polarizer, the proposed CP antenna utilizes a bicone antenna as the omnidirectional LP radiator. Two additional anti-reflection layers are used on the inner and outer surfaces of the conformal polarizer to reduce reflections. Simulation results show that the antenna has an ARBW of more than 60° from 27 to 33 GHz.