Wideband Circularly-Polarized 3D Antenna Array for Millimeter-Wave Applications

This paper presents a novel millimeter-wave wideband circularly-polarized 3D helical array antenna that works at 30 GHz. To design an antenna with wide circular polarization (CP) bandwidth, a 2 x 2 axial-mode helical structure is fed by using a sequential phase feeding network. The antenna array covers a wide frequency band from 26.4 GHz to 34 GHz with an achieved maximum gain of 11 dB and an axial ratio of less than 3 dB in the whole band. Moreover, the radiation pattern of the proposed antenna has a right-handed circular polarization (RHCP) with side-lobe level below -10 dB. Subsequently, the proposed antenna array can be a good candidate for millimeter-wave communication systems around 30 GHz.