Pazynin V. Modeling and analysis of processes of passive and active compression of electromagnetic pulses of microwave and optical bands

An important scientific and applied problem of construction of rigorous mathematical models of transient processes under passive (dispersive) or active (resonant) compression of electromagnetic pulses (EMP) was solved in this thesis. The object of the study was the processes of propagation and scattering of electromagnetic waves in dispersion guide structures and in resonance structures, whose electrical parameters can change over time. The purpose of the work was to build rigorous and effective approaches to solving problems that arise during the analysis and synthesis of passive and active EMP compressors and to study with them the physics of the processes in such devices. Rigorous analytical and numerical methods were used – the time reversal method, the incomplete separation of variables method, the exact absorbing conditions method, the finite-differences time-domain method, as well as mathematical modeling and computational experiment. The exact absorbing conditions method was developed. This method with the finite-difference method made it possible to effectively build the rigorous solutions of the open initial-boundary value problems of electrodynamics with arbitrary geometry of sources and scatterers. For the first time, the time reversal method was adapted for rigorous modeling of passive EMP compression in guide structures with the group velocity dispersion. A step-by-step scheme of model synthesis of active EMP compressors based on the solution of initial boundary-value problems describing EMP transformations at corresponding electrodynamic units was developed. The results obtained can be applied in the design of electromagnetic pulse compressors.