A radar for decisive target detection and tracking requires wideband, high return loss, and high efficiency antenna array. In this paper, a 16 element staked-patch microstrip antenna array is presented at Ku-band with very low reflection coefficient for radar system. An aperture coupled feeding approach for a stack patch antenna is employed for wide bandwidth. A thin and low-loss tangent material, Taconic TLY-5, is used in the design of an antenna array to minimize the surface current loss and dielectric loss. Moreover, the antenna is designed with good impedance match, −30 dB, for high efficiency, by optimizing the stacked patches and utilizing reactive loading from u-slit on patch. For a low reflection coefficient antenna array over a wide bandwidth, an adequate feeding network consists of a compact and meandering stripline with metal-post around it is developed. The stripline configuration with metal-post minimizes crosstalk and lateral leakage. The feeding network developed has low reflection coefficient of −30 dB for the target band. The simulated feeding network loss is also low, 0.5 dB. The overall size of the 16 element array is compact, 295 mm × 30 mm (14λ × 1.425λ). The antenna array performance gives a reflection coefficient of −30 dB in the range of 14–14.5 GHz and total efficiency of 80%. The gain of the array is 21.5 dBi at 14.25 GHz.