This paper presents an array antenna with wide bandwidth for tunnels under construction. The antenna is composed of eight sequential-fed patch antenna elements and a broadband feeding network capable of power division and phase shifting. By loading rectangular branches and arc-shaped chamfer parasitic elements, the performance of circular polarization is improved. Furthermore, to reduce the diagonal cross-polarization effectively, the eight antenna elements are rotationally laid out. The proposed antenna array achieves a simulated -10 dB impedance bandwidth of 73.3% (1.32-2.85 GHz), a 3dB AR bandwidth of 65.1%(1.45-2.85 GHz), and a peak gain of 15 dBic, which justify the applicability of the proposed antenna array for tunnels under construction.