A Wideband Endfire Circularly Polarized Antenna for Millimeter-Wave Application

This paper introduces a wideband circularly polarized (CP) endfire antenna for millimeter-wave application. The proposed antenna derived from a modified dipole structure with expanded bandwidth. Hence, broadband endfire CP radiation is formed. To further improve the gain, a 3D-printed polarizer is introduced on the end of the proposed dipole structure, forming dielectric polarizer loaded dipole (DPLD) antenna. The proposed endfire antenna can achieve axial ratio (AR) bandwidth of 30.2% from 66.4 to 90 GHz and a peak gain of 12.3 dBic. In addition, the proposed endfire antenna yields the characteristics of planar structure, low-cost and wide bandwidth, rendering it suitable for high-speed millimeter-wave applications.