Techniques of designing a smart antenna system are described. An antenna system includes at least two integrated antenna units arranged with a predefined angular angle therebetween to form a desired antenna pattern without any significant nulls. According to one aspect of the techniques, at least two sets of antenna units are interlaced but polarized differently to form an integrated antenna unit. Each of the antenna units is formed with an array of antennas. The antennas in an array or the antenna units in an integrated antenna unit can be selectively energized to form a desired antenna pattern in accordance with a signal determined from radio frequency signals communicated between a device equipped with the antenna system and another device (e.g., a Wi-Fi router in communication with a mobile device), where the desired antenna pattern provides an optimized antenna pattern to facilitate seamless or QoS communication between the two devices.