Regulate drain‐shield relative positioning and contact for mitigating radiated emission from USB cables

Abstract

This letter delves into the influence of drain wire design on electromagnetic radiated emission (RE) from a commercial universal serial bus (USB) cable operating in a high‐speed data transfer mode. The investigation involves an experimental comparison of measured RE across various retrofitted cables. Notably, it is demonstrated that the distribution of contact points on the drain‐shield has negligible effects on RE. Conversely, relocating the drain wire externally to the shields and minimizing the distance with respect to the grounding connector leads to a significant reduction in RE, particularly within the sub‐MHz frequency range. Consequently, regulatory proposals are put forth to diminish overall RE and enhance the RE compliance of USB cables.