Characteristics of Coupled Differential Pairs from the Perspective of Increasing their Immunity to Intentional Electromagnetic Interference

Radio electronic devices operating in differential mode, such as those used in automatic control systems, can be adversely affected by electromagnetic interference. This is particularly relevant for interfaces like USB and LVDS, which are commonly employed in such systems. Ensuring the reliable operation of these systems requires measures to protect against unwanted interference. This work aims to develop a method for tracing two differential pairs that increases their immunity to electromagnetic interference, thereby enhancing system reliability. This paper presents the results of electrodynamic simulations of single and coupled differential pairs using COMSOL Multiphysics software. Time-domain analysis, frequency response analysis, and signal integrity analysis were performed to assess the impact on reliability. Results indicate that adding a second differential pair significantly improves electromagnetic interference suppression, leading to more robust and reliable system operation. Ultra-wideband interference attenuation increased by more than two times, and narrowband interference attenuation by more than five times. The optimal distance between the pairs ensures the best signal integrity, further contributing to reliable data transmission.