GHz twisted differential line structure on printed circuit board to minimize EMI and crosstalk noises

The concept of twisted pair on the cable interconnection can be readily applied to the differential lines on printed circuit board (PCB), which enables enhanced immunity against crosstalk and radiated emission. In this paper, twisted differential line (TDL) is implemented on PCB and fully characterized. First, the transmission characteristics of TDL including propagation constant and differential impedance are extracted by using 3D full-wave analysis. The potential of TDL for the transmission of over GHz signal and enhanced immunity against crosstalk and radiated emission is clearly shown. Second, the measurement results reconfirm TDL's capability as a good transmission line structure over several GHz. Also, it is modeled by a simple equivalent circuit, based on measurement results. Third, the enhanced immunity of TDL against crosstalk and radiated emission is clearly demonstrated by measurement results. TDL is compared with other transmission line structures showing its superiority. Finally, several ideas to improve TDL's performance are suggested and verified to be useful.