Overview of Common-Mode Noise Suppression Techniques: From Reflection to Absorption

Today’s fast-growing wireless communication technology has greatly increased the demand for the transmission of high-quality signals with high data rates. Because of its intrinsic advantages of high immunity to external noise, lower electromagnetic interference, harmonic suppression, and better linearity, differential signaling is preferable to single-ended signaling for many applications, including high-speed digital circuits, RF systems, and integrated circuits based on CMOS technology
[1]

[2]
,
[3]
,
[4]
. However, in real-world circuit applications, differential signals are usually accompanied by destructive common-mode (CM) noise, which may be induced by asymmetric differential transmission paths with bending or length mismatch. On the other hand, imbalance of the differential signal channels, including amplitude swings and differences between rising and falling times, could also contribute to CM noise. In addition, the radiation emission caused by CM noise is much stronger than the differential signals, leading to a reduced system reliability
[5]
. Therefore, CM suppression has been an inevitable challenge for differential circuits and systems.