Using Square Cross Structure for Far-End Crosstalk Reduction on Microstrip Signal Lines in DDR5

Far-end crosstalk (FEXT) becomes one of the most critical factors affecting signal quality (SI) in high-density and high-speed printed circuit boards (PCBs). In this paper, a new method of using square cross structure (SCS) is proposed to reduce FEXT for microstrip signal lines in DDR5. According to the simulated S-parameters results, with the utilization of this method, the FEXT can be suppressed to be less than −24 dB in a wide frequency range (0~16GHz). Moreover, the FEXT decreases by more than 20 dB around the main frequency (3.2 GHz) of DDR5, compared with the signal routing without the SCS. Then, the time domain simulated results also show that the peak of FEXT noise is below 2.0 mV. Therefore, it can be concluded that this method has a great potential in FEXT reduction for microstrip signal lines in DDR5.