A Dual-Linear Polarized Ultrawideband TCDA with Low-Profile

In this paper, we propose a dual-linear polarized ultrawideband tightly coupled dipole array antenna (TCDA) based on the strong mutual coupling effect, The overall geometry consists of cross-located tightly coupled dipoles integrated with a folded Marchand balun that serves as an impedance transformer to achieve a wideband feeding network. The design achieves VSWR< 3.5 across 5.2 - 38.8 GHz at broadside, and VSWR< 3 across 5.7 - 39.6 GHz when scanning down to 60° in the E-, H- and D-planes except 6.8-8.3GHz when scanning to 60 °in the E-plane. For radiation performance, a resistance plane is added to eliminate short-circuit resonance. A strong resonance generated by the 60° scan of the E - plane is moved out of the working frequency band by adding a short-circuit line. The unit cell's total height is only $0.12 \ \lambda_{low} \ (\lambda_{low}$ is the vacuum with the lowest frequency wavelength).