Highly Linear and Highly Efficient Dual-Carrier Power Amplifier Based on Low-Loss RF Carrier Combiner

This paper presents a novel power amplifier (PA) architecture for amplifying dual-carrier signals with simultaneous high efficiency and high linearity. This dual-carrier PA is based on two high-efficiency PAs and an innovative RF carrier combiner, which is a diplexer implemented with bandstop filters (BSFs). This special BSF diplexer is capable of combining two carriers with ultra-narrow frequency spacings, e.g., down to 0.25% fractional bandwidth, while maintaining a low combining loss of 1 dB. Compared to conventional diplexers implemented with bandpass filters, this new technology leads to minimized resource usage for achieving the same combining performance. The integrated PA exhibits excellent performance when amplifying dual-carrier signals in terms of linearity and efficiency. Specifically, third-order intermodulations of 40 dBc were measured with 70.2% (60.8%) power-added efficiency for carrier spacing of 10 MHz (5 MHz).