2 to 18 GHz ultra-wideband dual-linear polarized phased array with 60° scanning

In this paper, we present for the first time a novel dual-linear polarized phase array based on tightly coupled dipole topology. The array operates across an impressive 9:1 impedance bandwidth spanning 2-18GHz with scanning capability down to 60 ^o from boresight. Importantly, the array is extremely low profile, with a total height less than 12mm (λ _low /10). The overall geometry consists of cross-located tightly coupled dipoles integrated with a folded Marchand balun that serves as an impedance transformer and a feeding network. The traditional dielectric superstrate is replaced with double layers of frequency selective surfaces (FSS) to enable scanning down to 60 ^o in both E and H plan across the entire band. Notably, the polarization and port-to-port isolations are kept at least 40dB at broadside and 30dB with scanning cases. Such high isolation makes this array great candidate for Simultaneous Transmit and Receive (STAR) systems.