It is known in the field that conventional single-port antennas cannot provide both advantages of high gain and broad angular coverage. It is also known in the field that, for modern mobile communication systems, the transmitted signals generally include not only information data, but also pilot signals, which are used for both estimating real time channel responses and facilitating signals reception. Therefore, through a proper baseband signal processing arrangement, it is possible to effectively combine sub-arrays output signals of a multi-port antenna to substantially enhance interested signals. The present invention therefore makes use of the resources provided by the pilot signals to construct a novel antenna structure having multi-port sub-arrays and a baseband signal processing function unit, to simultaneously offer the advantages of high gain and broad angular coverage. In addition, the present invention is particularly suitable for use in millimeter wavelength antennas.