Measurement of load-pull performance in the power smith tube using a tunable varactor matching network

Future radar transmitters will require a fast reconfiguration of their radio-frequency circuitry in order to adapt to changes in operating frequency and spectral output while maintaining high power-added efficiency. In this paper, transistor load-pull measurement results are displayed in the Power Smith Tube using measurements from a tunable-varactor matching network. Measuring load-pull characteristics and plotting them in the Power Smith Tube is a preliminary step toward the implementation of the Power Smith Tube in real-time optimization using the tunable-varactor network. Visualization of the tunable-matching network load-pull results can be used as an aid in designing for optimum power-added efficiency while meeting adjacent-channel power ratio requirements.