A wideband planar dipole antenna comprises a substrate and two antenna bodies. Metal conductor is printed on the single surface/double surfaces of the substrate to form the antenna bodies. With a dipole antenna architecture, the antenna bodies are manufactured as loop structures similar to concentric circles. The loop structures can be of rectangular or circular shapes. Loops of metal conductors with different lengths resonate to obtain similar but different frequencies. Each path of every antenna body can be finally connected with a metal conductor sheet capable of changing to any shape. Every path can interfere with adjacent paths to achieve the wideband effect. An asymmetric mechanism can be added in one of the antenna bodies. Besides letting the antenna have the resonance effect of the symmetric part, the loop path at the signal source can also be increased to enhance the receiving performance of the antenna.