High-Performance Balun for a Dual-Polarized Dipole Antenna

This paper proposes a detailed analysis on the operation of a high-performance balun for a dual-polarized dipole antenna. The main feature of this balun is to transform a coaxial feed into a differential feed which can enable very high performance for dual-polarized configurations. First, we identify the key factors that allow the new balun to achieve better differential properties respect to the feeding approach typically found in the literature. Second, we investigate the balun properties and the achievable antenna performance with extensive simulations. Next, we prototype and measure the antenna proving that very high port-to-port isolation and low cross-polarization level (XPL) can be achieved over a broadband operation by means of this balun. Finally, we further investigate the operation of the balun through its physical decomposition revealing the minimum requirement to achieve high port-to-port isolation in dual-polarized dipole antennas.