Method and apparatus for automatically tuning an impedance matrix, and radio transmitter using this apparatus

摘要

The invention relates to a method and an apparatus for automatically tuning an impedance matrix, for instance the impedance matrix seen by the power amplifiers of a radio transmitter using a plurality of antennas simultaneously, and to a radio transmitter using this apparatus. An apparatus for automatically tuning an impedance matrix has 4 user ports and 4 target ports, and comprises: 4 sensing units; a signal processing unit, the signal processing unit estimating real quantities depending on the impedance matrix presented by the user ports, using the sensing unit output signals obtained for 4 different excitations applied successively to the user ports; a multiple-input-port and multiple-output-port tuning unit comprising adjustable impedance devices; and a tuning control unit delivering tuning control signals to the multiple-input-port and multiple-output-port tuning unit, the reactance of each of the adjustable impedance devices being mainly determined by one or more of the tuning control signals.