EMC and signal integrity design considerations for flexible printed interconnects in automotive data-bus applications

Flexible printed circuits (FPCs) are already widely used to connect printed circuit boards in compact systems such as smartphones, tablets and laptops, where weight and space are at a premium. The latter are also increasingly important issues in the automotive industry, suggesting that flexible printed interconnects could also offer advantages in vehicle applications. This paper therefore discusses various considerations that are important in designing FPCs that could replace the unshielded twisted pair cables that are conventionally used to implement differential signalling data networks in vehicles. The parameters considered here include the differential mode impedance characteristics, electromagnetic compatibility and signal integrity performance, as well as mechanical flexibility.