A Millimeter-Wave Dual-Polarized Endfire Antenna With Ultrawideband and High Isolation for 5G Multibeam Systems

A ultrawideband, high isolation dual-polarized endfire antenna is presented in this article. Based on the high isolation of the substrate integrated waveguide (SIW) and stripline, we innovatively developed an SIW-fed magnetoelectric (ME) dipole as the vertically polarized (VP) endfire antenna and a stripline-fed tapered slot antenna (TSA) as horizontally polarized (HP) endfire antenna. These two antennas realize ultrawide bandwidth and can share a radiation aperture. Meanwhile, the ME dipole acts as a parasitic structure, which greatly improves the impedance matching of the TSA in the working band. Due to this innovative design, the proposed dual-polarized endfire antenna realizes an operating bandwidth of 60% and a port isolation level exceeding 35 dB. To satisfy the requirements of 5G communication systems, we designed a multibeam antenna system composed of seven dual-polarized endfire antennas and a 3-D-printed Luneburg lens. The measured results indicate that the multibeam antenna achieves an overlapped bandwidth of 58% and a maximum gain of about 20.5 dBi. The gain variation within the scanning range of ±66° was less than 1 dB. With the merits of low cross-polarization, wideband, and high isolation, the presented dual-polarized antenna is an ideal candidate for 5G millimeter-wave (mmWave) systems.