Control design in the harmonic domain for microwave and RF circuits

Different approaches for stability analysis of large-signal steady states in the harmonic domain have been developed in recent years. Particular efforts have been focused on microwave and RF circuit design, where harmonic balance (HB) techniques are used extensively. In this work, frequency-domain control-design techniques are proposed in order to improve the stability margins of large-signal steady states. The methodology is based on circuit linearisation around the steady state under study and the calculation of the corresponding linear model through frequency domain identification techniques. To validate the proposed approach, the stabilisation of a circuit based on a varactor diode is presented.