Differential Trace Using Short-Circuited Slotline for Common-Mode Noise Suppression

In this article, a differential trace using the short-circuited slotline is proposed to efficiently suppress the common-mode noise induced by the differential trace bend. Since the short-circuited slotline is implemented on the ground plane of the differential trace, no space is occupied by the short-circuited slotline on the printed circuit board (PCB) surface, releasing more space for the differential traces routing on the PCB surface. As compared with the differential trace without the short-circuited slotline, the differential-mode transmission is increased from –6.94 to –4.6 dB. The differential-to-common-mode conversion is substantially reduced from –5.55 to –18.21 dB, and the differential-to-common-mode reflection is reduced from –14.96 to –19.46 dB. Besides, the time-domain common-mode noise is greatly reduced from 10% to 1.6%. To enhance the performance, a differential trace using the short-circuited slotline with the wide trace is proposed. The differential-to-common-mode conversion is further reduced from –18.21 to –20.72 dB, and the differential-to-common-mode reflection is further reduced from –19.46 to –21.19 dB. Besides, the time-domain common-mode noise is further reduced from 1.6% to 1.2%.