Real-Time Amplifier Optimization Algorithm For Adaptive Radio Using A Tunable-Varactor Matching Network

Fast load impedance tuning of a varactor diode matching network to maximize amplifier gain in real-time reconfigurable circuitry is demonstrated. A published tunable varactor-diode matching topology is designed for operation at 1.3 GHz to provide significant Smith Chart coverage. A steepest-ascent algorithm is applied for fast optimization, and measurement results indicate excellent convergence from multiple starting points within the Smith Chart. Algorithm data compares well with traditional load-pull results measured with both a commercially available tuner and the tunable-varactor network, and searching with the varactor tuner search is much faster than a traditional mechanical tuner.