EMC comparison of unshielded twisted pair and shielded twist pair in automotive CAN-bus

EMC performance of transmission medium in real time on-board network is one of those important factors affecting the control property of the distributed system. Now twisted pair is the most commonly used transmission medium in vehicles. Twisted pair can be divided into shielded twisted pair and unshielded twisted pair. The difference between them is that the former one has a metallic tape which has some shielding effect. Theoretically shielded twisted pair should have better EMC performance, but in practical applications unshielded one may perform better. In order make a comparison of EMC performances for these two types of transmission medium used in automotive CAN-bus, firstly the paper develops testing plan and evaluation methods for EMC performance of twisted pair according to the existing standards. Then the testing plan is developed, afterwards test results are achieved and analyzed. Finally comparison is executed and suggestions of the selection of these two different twisted pair used in automotive CAN-bus are given.