Basic Approaches to Optimization of Round and Flat Cable Structures for Protection Against Ultrawideband Interference

This letter discusses approaches to conducting comprehensive optimization of devices that protect against ultrawideband interference, known as modal filters, based on two criteria. These devices can take the form of strip N-conductor structures with a various number of conducting layers, as well as cables. When designing them, during optimization, developers need to simultaneously consider several factors (e.g., the level of interference attenuation in a 50- $\Omega $ matched path with minimal mass and dimensional parameters) 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 them. Thus, the work details the main approaches to optimizing cable structures, including simultaneously several criteria. As global optimization algorithms, we consider a simple genetic algorithm, evolutionary strategies, and a random search method. The criteria include the amplitude criterion (minimization of the interference voltage at the structure’s output) and the matching criterion with the electrical path (minimization of reflections of useful high-frequency signals at the modal filter input). As the structures to be optimized, we take cable structures based on 3-conductor round and 2-conductor flat cables. This letter compares three algorithms, highlighting their advantages, disadvantages, peculiarities, and limitations in optimizing cable modal filters. Finally, we present practical recommendations for the use of optimization algorithms that are useful for designers of noise-suppressing cable devices.