A novel Tightly Coupled Array(TCA) is proposed in this paper. The array element is made of bow-tie dipole, and the array realizes ultrawideband by increasing the coupling between the units. By loading Resistive Frequency Selective Surface(RFSS) between array and ground plane, the antenna short-circuit point can be suppressed, and the impedance matching bandwidth can be increased significantly. In addition, the parasitic layer is designed to replace traditional dielectric-slab wide-angle matching layer, which makes the height and weight of the antenna are greatly reduced and the scanning characteristics of the array are improved. The simulation results show that the antenna achieves 1.5-14 GHz bandwidth for Voltage Standing Wave Ratio(VSWR)<2, and realizes 45°scanning range at E-plane and H-plane.