Wideband High-Gain Low-Profile Endfire Linearly/Circularly Polarized Antennas Based on Magnetic Dipole Directors for Millimeter-Wave Applications

Wideband high-gain low-profile endfire linearly polarized (LP)/circularly polarized (CP) antennas for 5G millimeter-wave (mmWave) applications are presented in this letter. The basic structure of the antennas include a stripline fed horn as the feeder and multiple magnetic diploe directors (MDDs) printed on a single layer substrate. The stripline fed horn exhibits a wide bandwidth and stable endfire radiation, and magnetic dipole directors help further improvement the endfire gain. A LP antenna based on a LP feeder and vertically polarized (VP) MDDs (supporting VP resonance) working at the 5G mmWave band is first designed. Then, on this basis, CP antenna based on a CP feeder and dual-polarized MDDs (supporting two orthogonal polarized resonances) working at the same band is designed. The two proposed antennas with the low profile of 0.14?(0) are fabricated and measured, both of which show good impedance matching, high gain, and low cross polarization within the 5G mmWave band.