Microwave network analysis transitions from lumped-element circuit theory (Kirchhoff's laws) to distributed field descriptions by defining terminal voltages and currents via surface integrals of electric and magnetic fields, respectively. The core principle involves characterizing multi-port networks using scattering matrices (S-parameters), which relate incident and reflected wave amplitudes at defined reference planes where multiple modes can be represented as distinct ports. This domain specifically addresses high-frequency electromagnetics where circuit dimensions are comparable to wavelengths, necessitating a hybrid approach that combines Maxwell's equations with network theory concepts such as reciprocity and losslessness for system characterization.
Prerequisite chain context: requires Frequency Domain Analysis versus Time Domain Concepts in Signal Processing.