A smart antenna is provided, which may include a plurality of antenna units and a controller. The controller may be coupled to the antenna units. The controller may scan an angle range by a first angle interval according to a characteristic vector of the antenna units and an initial angle; if the power change between any two adjacent scanning points is negative, the controller may multiply the first angle interval by a number to generate a second angle interval, and keep scanning the angle range by the second angle interval; when the controller completely scans the angle range or the power change between any two adjacent scanning points is positive, the controller may generate a power spectrum.