摘要 |
The present invention relates to a method and an arrangement for optimizing the efficiency of a power amplifier ( 1 ) that is utilized for transmission of radio signals in a portable radio communication device, such as a mobile phone. The impedance loading the power amplifier ( 1 ) is controlled by a controller ( 5 ) in dependence on a transmission power of the portable radio communication device, wherein the radiating impedance of an antenna element ( 2 ) loading the power amplifier is controlled in dependence of the desired load impedance. Preferably, the changing of radiating impedance is performed by changing a capacitive coupling between the antenna element and a ground element or by changing the size of the antenna element. Better efficiency and bandwidth are thereby attained. |