State-space modelling of slow-memory effects based on multisine vector measurements

Non-linear microwave devices and circuits often exhibit slow-memory effects. When subjected to two-tone, or more general multisine excitations, the characteristics of these devices and circuits depend on the offset frequency between the tones. Since modulated excitations are an integral part of telecommunication systems, models aimed for circuit and system design should be able to accurately represent slow-memory behaviour. In this work, we develop a modelling procedure based on the state-space modelling approach to accurately incorporate these slow-memory effects. The technique is experimentally demonstrated on a high electron mobility transistor (HEMT).