Dual-polarized magnetic-current array antennas with high gain and low profile

Two sets of feeding networks are usually needed to achieve a dual-polarized high-gain planar antenna, not only leading to a complicated configuration but also to reduced efficiency. A simple feed structure and strategy are therefore in high demand for dual-polarized high-gain planar antennas. Directed at this requirement, we first present a series-fed dual-polarized slot array with a single-layered substrate. Two orthogonal magnetic-current arrays were positioned at the opposite sides of a single-layered substrate, leading to high gain and high port isolation. A novel scheme to achieve dual-polarized, high-gain, and low-profile antennas using the higher-order-mode microstrip antenna was then demonstrated. By loading half-wavelength slots at the electric-field nulls of a higher-order-mode microstrip antenna, a multiple-element in-phase magnetic-current array was constructed within a low-profile cavity with a simple feeding strategy. As a proof of the concept, two dual-polarized high-gain microstrip magnetic-current array antennas, utilizing the TM 50 and TM 90 modes of a microstrip antenna were investigated. These magnetic-current array antennas had the merits of having a low profile, simple feeding, and high isolation, promising a huge potential in diversity and MIMO applications.