A passive equalizer based on a stub and broadside coupled lines for high-speed data transmission

With the demand of signal integrity in high-speed digital communication systems, a passive equalizer is proposed to enhance the quality of eye diagram for long-distance data transmission. It is designed with a stub for reflections and broadside coupled lines for tight coupling, which result in de-emphasis of low frequencies and pre-emphasis of high frequencies, respectively. The geometric and resistance parameters are optimized. In comparison with the conventional T-shaped counterpart, the frequency-domain magnitude flatness and the time-domain eye diagram characteristics are both improved, which have been demonstrated by simulations and measurements.