An integrated wideband power amplifier for cognitive radio

This paper presents the development of the wideband power amplifier (PA) for application to intelligent cognitive radios. The load-tracking based on the frequency-varied load-pull technique is proposed for the PA design. The load impedance tracking is realized by filter network synthesis. A 3-7.5-GHz broadband PA is demonstrated in 0.15-[micro]m InGaAs pseudomorphic HEMT technology. Operated at 3.5 V, the [P.sub.1 dB] and power-added efficiency of the PA are better than 21.4 dBm and 20%, respectively. Index Terms--Cognitive radio (CR), frequency agile, load-tracking, power amplifier (PA), pseudomorphic HEMT (pHEMT), software-defined radio (SDR), wideband.