Identifying Multiple Reflections in Distributed-Lumped High-Frequency Structures

A method for precise identification of reflections in mixed distributed-lumped high-frequency structures is proposed. The system structure that can be described by this model class is a cascade of transmission lines tapped by lumped elements. Here, multiple reflections are allowed to occur and they are identified. Reflections can be closely spaced and there is no restriction imposed by the model on the magnitude of the reflections. Note that most models in the literature are restricted to reflections with small magnitudes. Using a finite sum of delayed damped complex exponentials (Cisoids) to attain the initial delay values and modeling each reflection with a rational model allows to identify reflections with high values of magnitude. When applied on a measurement example, the method identifies all the reflections that are present, whereas the order of the model remains reasonably low.