Influence of Failures in Flexible Printed Cables with Single Modal Reservation on the Attenuation of an Ultra-Short Pulse

This paper considered the ability of flexible printed cables (FPCs) with single modal reservation (MR) to attenuate ultra-short pulses in various types of failures. We investigated four FPC structures by modifying modal filters (MF) on a double-sided printed circuit board (PCB). We considered five cases that simulate failures, including short circuit (SC) at the output, open circuit (OC) at the output, SC at both input and output, OC at both input and output, and SC at the input together with OC at the output. The simulation was performed with the real structure dimensions. The simulation results showed that for each structure, in the case of failure at one end only, the attenuation became greater (for three structures) or equal (for one) to the attenuation before failure. The FPC was constructed using a double-sided PCB with an arrangement of signal and reference conductors that employed broad side and edge coupling. This configuration was modified by adjusting the MF to achieve the desired performance and resulted in a maximum attenuation of 5 times (U
max
=0.195 V at OC-50, whereas before failure U
max
=0.4 V). In addition, the attenuation was also observed when failure was at both ends at the same time (SC-SC and OC-OC), although it was much smaller (1.3-1.9 times). In some cases, the attenuation at SC-OC was even greater than in the before failure case and in the case of failure at one end only.