A Gain-Enhanced Outphasing Power Amplifier

A dual-input outphasing power amplifier (PA) is presented in this work. To overcome the gain limitations of conventional outphasing PAs, a gain-enhanced single-stage branch amplifier is used in which a unilateralization technique yields 12.6 dB gain in deep compression. First, the branch PA is characterized under load-pull to verify that the unilateralization technique is compatible with load modulation. Then, a combiner is designed using the generalized black-box technique and synthesized as stepped-impedance lines. The 37.9 dBm peak power PA demonstrates 18.5 percentage points of PAE benefit at 6-dB output back-off compared to operation without load modulation.