Abstract: –To realize X-band ultra-wide-angle scanning, the paper proposes a novel tightly coupled array antenna unit design, and combines the equivalent circuit to analyze and optimize antenna parameters. With the integrated Marchand balun, dipole and balun can be fabricated on the same PCB, thus reducing antenna’s weight and cost. Introducing the vertical parasitic superstrate and horizontal dielectric layer above the antenna aperture, the two work together to improve the impedance transformation during wide-angle scanning. The results show that the scanning angle ranges up to 80° in E-plane while 70° in H-plane, with an active VSWR<3, in X-band (8–12 GHz). The antenna is simple, compact and easy to fabricate.