Description of Microwave Circuits via the Reduced-Basis Method Giving Physical Insight

A description of electromagnetics by means of the reduced-basis method (RBM), which gives physical insight, is detailed. Contrary to what has been previously done to get further insights from the electromagnetic behavior, a reliable reduced-order model completely describing a microwave circuit in a frequency band of interest is carried out. Following a theoretical analysis starting from time-harmonic Maxwell’s equations, we identify the dominant contributions to electromagnetics in a band of analysis. Making use of the reliable reduced-order model, we present the electromagnetic information in that reduced-order model in a more insightful manner, using a specific dynamical system representation of electromagnetics. As a result, a full-wave coupling matrix completely describing electromagnetics in the band of analysis is identified, where no narrowband approximation is considered, such as it is the case in classical coupling matrix circuit theory. No approximation is taken into account other than carrying out the analysis in a given frequency band, which can be arbitrarily large. The proposed approach provides a way to understand electromagnetics, where a full-wave coupling matrix allows the description of electromagnetics in a band of interest as a simple physically insightful circuit, and not the other way around. Finally, several real-life microwave circuits, such as a dual-mode filter and diplexer, will illustrate the capabilities and efficiency of the proposed approach.