A dual-polarised broad-band array antenna with high gain is presented for base transceiver station applications. The structure of the proposed antenna consists of four radiating elements and L-shaped feed lines. Each radiating element includes two suspended copper plates. The electromagnetic waves have been coupled to radiating elements through feed lines. The ports’ isolation is obtained using a cubic isolator between two L-shaped feed lines. The high gain of the proposed antenna is obtained using the sum of four elements placed at a specified distance from each other. A prototype of the proposed antenna is fabricated on a flame retardant-4 substrate. Through experiments carried out within the frequency range of 1.6–2.3 GHz, the bandwidth, return loss, isolation between ports, and the gain of this prototype are obtained to be 66%, <−10 dB, better than −15 dB, and almost 11 dBi, respectively. In addition, within the frequency range of 3.4–3.7 GHz, the values of the same parameters are obtained to be 8.4%, <−10 dB, better than −15 dB, and almost 5.8 dBi, respectively.