1. A method for radio reception with multiple antennas in a given frequency band, using N antennas, where N is an integer greater than or equal to 2, the method comprising the steps of: amplifying n electrical signals, where n is an integer greater than or equal to 2 and less than or equal to N, using a multiple-input-port and multiple-output-port amplifier comprising n input ports, m output ports, where m is an integer greater than or equal to 2, and p adjustable impedance devices, where p is an integer greater than or equal to m, each of the adjustable impedance devices having a reactance at a frequency in the given frequency band, the input ports presenting, at said frequency in the given frequency band, an admittance matrix referred to as the admittance matrix presented by the input ports, the reactance of any one of the adjustable impedance devices having an influence on the admittance matrix presented by the input ports, the reactance of any one of the adjustable impedance devices being adjustable by electrical means, each of the output ports delivering a signal; processing m digital signals, each of the digital signals being mainly determined by one and only one of the signals delivered by the output ports, to estimate one or more quantities representative of a channel matrix between a plurality of signals sent by a transmitter and the m signals delivered by the output ports, and to deliver a tuning instruction as a function of said one or more quantities representative of a channel matrix; using the tuning instruction to obtain one or more tuning control signals, the reactance of each of the adjustable impedance devices being mainly determined by one or more of the tuning control signals.