Future developments and technology options in Cellular Phone Power Amplifiers: from power amplifier to integrated RF front-end module

Millions of cellular phone power amplifiers (PA) are produced every day worldwide using a great diversity of technologies. This is true both for the active devices, where various silicon as well as GaAs transistors are being used, and for the PA design, in which MMIC, module and discrete solutions compete. This paper gives an overview of the various options for technological and architectural choices and their influence on PA performance, notably efficiency and linearity. It sketches the future of PA development towards more functional integration, which will be obtained by two paths: integration on chip and added functionality in modules.