Fujitsu Laboratories Ltd. announced the development of circuit technology that enables industry-leading electrical efficiency (the ratio between output power and consumed power) for wireless transmission power amplifiers used in radio-frequency wireless devices, such as mobile phone base stations.

In recent years, due to the widespread adoption of smartphones, there has been a constant rise in the number of mobile phone base stations. These base stations and other radio-frequency wireless equipment typically consume a substantial amount of electricity. Transmitter power amplifiers, which are used to amplify transmission signals, consume a particularly large amount of power, which has led to a need for improved electrical efficiency. By applying outphasing(1) in a transmitter power amplifier, Fujitsu Laboratories has developed a compact, low-loss power combining circuit and a high-precision phase error compensation technology based on digital signal processing. These technologies enable high-efficiency transmissions across more than 95% of the transmission duration, compared with 65% for existing amplifiers. In addition, Fujitsu Laboratories succeeded at developing a prototype transmitter power amplifier with a peak output power of 100 W. This development improved average electrical efficiency during transmission, from the current rate of around 50%, to 70%(2).

The new technology will help pave the way toward lower energy consumption for mobile phone base stations and other radio-frequency wireless equipment.

Details of the technology will be announced at a monthly Institute of Electronics, Information and Communication Engineers' Technical Group on Microwave Engineering conference, to be held on October 24, 2013 at Tohoku University in Sendai, Japan.