Optimization of Protective Devices with Modal Phenomena Using Global Optimization Algorithms

The article discusses approaches to conducting comprehensive optimization of devices that protect against ultrawideband interference, known as modal filters. These devices can take the form of strip N-conductor structures with a various number of conducting layers, as well as cables. Optimization is one of the important stages of their design. Often, during optimization, developers need to simultaneously consider several factors that the final product must satisfy. Additional complexity in the optimization of such structures is due to the variability of geometric and schematic models of modal filters. This article combines the latest research in the field of their optimization using evolutionary and stochastic global optimization algorithms. Also, for the first time, optimization of cable structures according to two criteria simultaneously is presented. As algorithms, we consider simple a genetic algorithm, evolutionary strategies, and random search algorithms. In addition, we modify a classical evolutionary strategies algorithm to enable correct optimization of modal filters, and employ amplitude, frequency, and matching criteria to perform single and 2-criteria optimization. As the structures to be optimized, we take strip modal filters based on 3-conductor microstrip lines and 2‑conductor structures with broad-side coupling, as well as cable structures based on 3-conductor round and 2-conductor flat cables. Finally, we compare three algorithms, highlighting their strengths, weaknesses, peculiarities, and limitations in optimizing strip and cable modal filters.