Analysis of noise immunity and signal integrity for two differential transmission lines with non-reflective fnchs

The rapid development of digital technologies and the miniaturization of devices exacerbate the challenge of electromagnetic compatibility (EMC) at high frequencies and in dense component layouts. Differential transmission lines (DTLs) require efficient solutions to suppress electromagnetic interference without compromising signal integrity. This study analyzes the impact of an absorbing-type low-pass filter (LPF) on the noise immunity and signal characteristics of microstrip DTLs. The DTL structure was designed with 100-ohm differential-mode impedance matching, and simulations were conducted in both the time and frequency domains. The LPF implementation increased the attenuation of ultra-wideband and narrowband interferences by 6.69 and 7.41 times, respectively, while maintaining the signal bandwidth. Reflection coefficients at the output were reduced in the stopband, and eye diagrams demonstrated minimal LPF impact on signal integrity. The results confirm the proposed method's effectiveness in enhancing DTL EMC, making it promising for high-speed interfaces.