Patent ID: 9041611
Filing Date: 2015-05-26
Classification: H03F,H03H

Abstract:
1. An automatic impedance matching method for a radiofrequency transmission channel comprising at least one amplifier, an antenna, a calculation processor, and an impedance matching network between the amplifier and the antenna, the impedance matching network comprising several impedances some of which have adjustable numerical values, the amplifier having a nominal load impedance for which the channel has the desired performance, the method comprising the following steps: measurement of an output current and an output voltage of the amplifier; calculation of a complex impedance defined by the ratio between the voltage and the current taking into account their phase difference, the complex impedance representing a current load impedance of the amplifier; calculation of an impedance of the antenna as a function of the current load impedance and as a function of known current values of the adjustable impedances of the impedance matching network; calculation of new values for the adjustable impedances of the matching network which allow an overall load impedance of the amplifier to be obtained as dose as possible to the nominal load impedance, based on the calculated impedance of the antenna; and control of the impedance matching network for adjusting the adjustable impedances to the new values, wherein the output current is measured by means of a measurement impedance which is an adjustable impedance placed in series between an output of the amplifier and the impedance matching network, and adjustment of this measurement impedance is controlled by the processor as a function of a desired operating frequency for the channel and of the nominal load impedance of the amplifier.