A communication device includes a wideband antenna, a reflector, and at least one metal loop. The wideband antenna is configured to cover an operation frequency band. The reflector is configured to reflect the radiation energy from the wideband antenna. The metal loop is positioned between the wideband antenna and the reflector. The distance between the wideband antenna and the reflector is shorter than 0.25 wavelength of a central frequency of the operation frequency band.