A Coupler-Feedback Technique for Power Amplifier Gain Enhancement

This work presents a gain enhancement technique for power amplifier (PA) design that uses a coupler around the core device to null its in-band S12. As a result, in-band stability is achieved without introducing resistive loss, and therefore a higher gain is achieved. A reference design using conventional matching and stabilization circuit topologies is also developed to serve as a performance benchmark. The two PAs have comparable saturated output power of 34 – 35 dBm over the approximately 2.65 – 3.10 GHz characterization range, but the coupler-feedback PA has on average a 6-dB gain improvement compared to the conventional design, and its large-signal gain at saturation is above 15 dB.