Dynamic Load Modulation Power Amplifier Using Tunable Impedance Transformer

power amplifiers are of great practical interest for wireless technology frontends. The design of the microwave power amplifier with load modulation network is discussed. The original design of the tunable impedance transformer allows load modulating at the output of a transistor is proposed. The proposed tunable impedance transformer is based on J-invertor where the transformation impedance are varied by tuning capacitors. A load-pull procedure for a GaN HEMT transistor is used to achieve optimal impedance range providing high-efficiency operation. Results of analysis of the proposed design of the load modulated power amplifier that contain proposed tunable impedance transformer demonstrates that load modulation technique allows enabling high-efficiency operation over 60% in a wide output power dynamic range (7 dB) at 5 GHz operation frequency.