Abstract: A dual-polarized antenna includes a ground plane, an inverted-F conductor unit with an inverted-F plane, an inverted-L conductor unit with an inverted-L plane and a stretched ground conductor unit with a T-shaped plane. The inverted-F plane is vertically connected to the inverted-L plane, the T-shaped plane and the ground plane respectively, and the T-shaped plane is vertically connected with the ground plane. Therefore, the inverted-F plane, the inverted-L plane and the stretched ground conductor unit correspond to each side of the ground plane respectively to form a dual-polarized radiation field.

Abstract: A data coupler includes an antenna substrate that is not electrically connected in a DC arrangement to an electric power line, is arranged adjacent to the electric power line, and is connected to a modem. A resonant circuit including an inductance element and a capacitance element is provided in the antenna substrate. In the resonant circuit, the inductance element is magnetically coupled to the electric power line. The resonant circuit transmits a radio-frequency signal superimposed on the electric power line to the modem. The resonant circuit also transmits a transmission signal from the modem to the electric power line.