Current-Injected Load-Modulated Outphasing Amplifier for Extended Power Range Operation

In this letter, the power range to be covered with maximized efficiency by a two-way outphasing amplifier (PA) is significantly extended, thanks proposed architecture injection of an external signal. Using reactively terminated quadrature hybrid coupler (QHC) as nonisolating combiner, Chireix topology transformed into slight variation in load-modulated balanced (LMBA) when auxiliary branch activated. This combined (LM) strategy provides nearly resistive loading individual PAs over wide range. An appropriate output network, approximating class-E/F2 operation selected GaN-HEMT device under such condition, leads remarkable drain figures at deep back off (OPBO). Values higher than 80%, 70%, and 60% have been measured levels 9.5, 13.3, 15 dB below its peak (45.7 dBm), respectively. A 5-MHz Long Term Evolution (LTE) signal peak-to-average ratio (PAPR) high 12.65 has reproduced average above 62% worst-case adjacent channel leakage (ACLR) −31 dBc.