Abstract
We proposed a broadband directional antenna array working at mobile communication frequency band, which achieves a relative bandwidth of 50.7%. This binary antenna array is fed by two branches of the balanced microstrip. To enhance the antenna bandwidth, we introduced a section of loading metal strip. The antenna prototype has a vertical bar S-11 vertical bar lower than -10 dB within the 1.5GHz to 2.52 GHz frequency band, particularly from 2.01GHz to 2.50GHz, the vertical bar S-11 vertical bar is lower than -15 dB. The gain varies with relatively small variation within the working band, which is 5.4 dBi to 8.7 dBi.