A Dual-Band Dual-Output Power Amplifier for Carrier Aggregation

This paper demonstrates a high-efficiency dualband RF power amplifier (PA) for sub-6 GHz 5G carrier aggregation. The dual-band PA is tested with modulated signals generated by a new algorithm designed to provide realistic waveforms for carrier aggregation scenarios, allowing flexible complex (IQ) modulated sequences with arbitrary peak-to-average power ratio (PAPR), bandwidth, and band distribution. A single-stage PA is designed with a packaged 6-W transistor and a diplexer-like output matching network that separates the two bands into two outputs. It achieves an output power of 36.7 and 37.1 dBm and a power-added efficiency (PAE) of 40.4% and 39.9% at 3.5 and 5.5 GHz, respectively. Under concurrent, dual-band drive with 10-MHz, 6-dB PAPR signals and with digital predistortion applied to varying frequency notch bandwidths, an average PAE of 25.6%, a normalized mean square error of 2.4%/1.0%, and an adjacent channel power ratio of -46.8/-48 dBc in the two bands (3.5/5.5 GHz) is measured.