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 0.14λ 0 are fabricated and measured, both of which show good impedance matching, high gain, and low cross polarization within the 5G mmWave band.