Ultra-Wideband and Wide-Scanning Dual-Linear Polarized Phased Array with High Polarization Isolation and Low Cross-Polarization

High performance ultra-wideband phase array antennas are critical to the success of future multifunction communication. This paper presents a novel dual-linear polarized phased array with low profile and 7:1 bandwidth. The overall geometry consists of orthogonal oriented tightly coupled dipoles with overlapping patch in order to reinforce the mutual couple between the adjacent elements. Notably, feeding Marchand balun is optimized not only for better impedance transformation, but also providing feedline with excellent electrical shielding. Double layers of dielectric are placed above the dipoles to achieve wide-scanning in each principle plane across the working band. Finally, the proposed antenna array, with total height less than $\lambda_{1\mathrm{o}\mathrm{w}}/10$ can realizes VSWR< 2.5 across operating band (2.5-18GHz) at broadside. Simulation for infinite array indicates the design can achieve Tx/Rx isolation around 50dB at broadside, isolation better than 30 dB can be achieved when scan to $45^{\mathrm{o}}\mathrm{i}\mathrm{n}$ E-/H-planes. Due to the low profile, the dual polarized array is demonstrated to have good polarization isolation of -50dB for most of the band at broadside, below -30dB when scan to scan to 45° in E-/H-planes. With outstanding features above, the proposed antenna array can find its application in wideband simultaneous transmit and receive (STAR) monostatic systems and those wireless electronic systems with multiple functions.