The invention relates to an antenna system for reception of channel signals from the UHF band by a receiver, comprising an electrically small antenna.The system also comprises, connected between the port connected to the antenna and that of the receiver, an active impedance matching device controlled by command signals depending on the quality of the signal received by the receiver to compensate for the impedance variations due to the environment associated with the antenna and to reject the frequencies of interfering channels adjacent to the reception channel without interfering with the active impedance matching of the antenna.