A wideband CP antenna by using 3D printing polarizer

A millimeter wave antenna with wideband circular polarization is presented in this paper. It consists of a feeding aperture and a cylinder polarizer. The feeding aperture is used to achieve a good matching performance. While a cylinder polarizer located in front of the aperture is utilized to realize circular polarization. A low-cost three-dimensional (3D) printing technology is applied to fabricate the proposed polarizer. The proposed antenna can operate from 45 to 75 GHz for reflection coefficient < −10 dB and from 49 to 66.5 GHz for axial ratio < 3 dB. Besides, the gain of the antenna can reach to 15 dBic. The height of the antenna is almost 1.2 λ
0
.