Designing power amplifiers? Use good excitation signals

The performance of any communication front-end depends largely on the efficiency and the linearity of the power amplifier. Power amplifiers are difficult to design since the available design techniques are not valid for the more complex modulation schemes used nowadays. Therefore, one needs to include information about these complex signals in the design strategy. But this information should be used such that it allows the designer to take good design steps. We reviewed the traditionally used load-pull design technique for power amplifier designs using multi-tone excitation signals to MIMIC the real excitation signals. This approach is illustrated on the loadpull characteristics of a 5 GHz power amplifier in 0.13 ¿m CMOS technology. This example shows the difference in design choices when using the correct excitation signals. Therefore, it illustrates the importance of these methods and the excitation signal used.