A 1.2 to 5.7GHz Multi-Mode Dual-Input Power Amplifier Using a Novel Sigmoid-Function-Based Power Splitter

We report a novel power splitting scheme for multi-mode dual-input power amplifier at sub-6GHz. The main novelty is the use of a sigmoid function to enable multi-mode load modulation over a wide frequency range with a modulated signal. One input signal is converted to two inputs based on the sigmoid function, which provides optimum signal magnitude and phase of dual input signals. The amplifier, using 0.15µm GaN HEMT FETs, achieved an averaged PAE of 36–56% with a modulated signal over 1.2–5.7GHz, which is 130% fractional bandwidth. This is a promising PA technology for 5G base stations, enabling operators to reduce their total cost of ownership.