Active Load-Pull System in Doherty Power Amplifier

In general terms, power amplifiers used in communications systems must be large enough to amplify envelope peaks. This leads to amplifiers that are designed to offer the best efficiency at peak power, while actually spending most of the time operating inefficiently, amplifying smaller signals. With the advancement in next generation communication systems, which employ signals with ever increasing peak to average ratio, the pressures on the PA design continue to grow.

Techniques such as Doherty amplifier structures are therefore used to extend high efficiency device operation to lower power levels, allowing for significantly improved average power amplifier (PA) efficiency. This white paper explains how the Mesuro Active Load-Pull measurement system can be used to aid the design and optimization of Doherty power amplifiers, and shows how the Measurement system can offer new, useful information that can improve Doherty designs.