Application Note: Mixed-Signal Active Load Pull: The Fast Track To 3G And 4G Amplifiers

The current trend towards increased data rates in mobile services has direct implications for the power amplifiers operating in these systems, which now need to be not only efficient but also wideband and, above all, linear. To operate efficiently, an amplifying device needs to see its optimum terminations at the input and output. Although basic amplifier theory suggests that an almost infinite number of harmonics need to be controlled to establish a particular device class of operation (such as (inv.) Class B, E, F),1 in practice, control of the fundamental, second and third harmonic is most of the time sufficient to achieve high performance.

Reprinted with permission of MICROWAVE JOURNAL® from the September 2010 issue. ©2010 Horizon House Publications, Inc.