Analysis of Asymmetric Structures with Triple Modal Reservation

Introduction. An original approach to electrical circuit reservation, referred to as modal reservation (MR), is developed with the purpose of increasing the reliability and functional safety of radio electronic equipment (REA). A specific feature of this method consists in the use of strong electromagnetic coupling between the conductors, thereby increasing the reliability and ensuring the electromagnetic compatibility of the device under development. Printed circuit boards (PCBs) with MR are conventionally constructed using a structure designed to maintain mirror symmetry along the vertical, and, in some cases, along the horizontal axis. Meanwhile, asymmetrical options for PCB layouts with MR have not been previously considered. Aim. To compare triple MR PCBs constructed using symmetrical and asymmetrical layout options to identify beneficial effects in the time domain. Materials and methods. Simulations were carried out in the TUSUR.EMC software environment without considering losses in the conductors and dielectrics. A mirror-symmetrical four-wire transmission line with edge and broad-side couplings was selected as the initial triple MR design. Results. No asymmetric sets of parameters that would attenuate the interference pulse of more symmetric sets (1 and 2) were found for all possible failure scenarios. However, sets 8, 9, and 12 allowed 2.38, 2.75, and 2.22 times higher ∆τ min values to be achieved compared to set 1 (whose ∆τ min value was greater than with symmetric set 2). Conclusion. The discovered sets 8, 9, and 12 show that the arrangement w1 = w2 ≠ w3 = w4, s1 = s2 can be used to reduce the probability of pulse overlap on actual devices, as well as to implement shorter-length PCBs compared to the symmetrical option without the risk of pulse overlap. The data obtained can be used when tracing PCB layouts in situations requiring an increase in the delay difference.