Single Modal Reservation of Flexible Printed Cables

Abstract

This paper considers a way to simultaneously ensure functional safety and electromagnetic compatibility using single modal reservation (MR) of flexible printed cables (FPCs). For this purpose, modal filters (MF) implemented in FPCs and on double-sided printed circuit boards (PCB) were analyzed. The analysis allowed us to choose structures that can be used to implement single MR in FPCs. For example, in these cables, the attenuation of ultra-wideband interference (UWB) depends on the conductors between which the action is applied. Additionally, the two-layer structure of FPCs allows for the UWB interference attenuation. The analysis includes the results of simulating three MF structures on the PCB. The possibility of attenuating the UWB interference in these MFs was demonstrated experimentally. The symmetry of the three MF structures allows them to be used for single MR, and a decrease in h allows for greater attenuation of the UWB interference. The three FPC structures formed by modifying the PCB MF were simulated with the real structure dimensions. We also investigated the effect of the distance between FPCs (from 10 to 250 μm) on the per-unit-length mode delay and the decomposition pulse amplitudes. In all structures, when the distance between the FPCs increases, the per-unit-length mode delays and the attenuation of the UWB interference decrease. The maximum attenuation was 4 times half the e.m.f.