Optimal Switching Order of a Reflection-Symmetric Flexible Printed Cable with Multiple Modal Reservation

The increase of functional reliability of radio-electronic equipment is achieved through redundancy of its most vulnerable blocks, nodes and interconnections. However, well-known redundancy methods have low interference immunity. Modal reservation (MR) can solve this problem. To minimize interference as much as possible, in this paper we propose to implement MR in flexible printed cables (FPC), and then in printed circuit boards (PCB). This implementation of MR will minimize the influence of interference. We estimated the attenuation of ultra-wideband (UWB) interference in a reflection-symmetric FPC after a simultaneous failure of two and three conductors. In fact, after the failure of two conductors, there are 2 possible options for switching to the reserving conductors. However, the variant of switching will depend on the second conductor that failed. Therefore, we determined the optimal switching order that allows us to achieve greater attenuation of UWB interference. The results showed that after the failure of the reserved and lower left reserving conductors, the maximum attenuation was 2.9 time. The optimal switching order is to switch to the lower right reserve conductor. When the reserved and right upper or lower reserving conductors failed, the maximum attenuation was 3.9 and 4.1 times, respectively. For both cases, switching to the lower left reserving conductor is optimal. After the simultaneous failure of three conductors, the attenuation was maximum and achieved 4.2 times. Thus, we demonstrated that after the simultaneous failure of two and three conductors in a reflection-symmetric FPC, the UWB interference can be attenuated to an acceptable level.