Design of Compact Defected Ground Structure for Differential Signal

In this paper, U-shaped defected ground structure to improve the signal integrity between the 500MHz and 1GHz frequency range is proposed. This structure is proposed to reduce the harmonic common-mode noise in the low voltage differential signaling (LVDS) system. Compare to other types of defected ground structure (DGS), the proposed structure has a wide stopband frequency range and small size, allowing less circuit area to be used. It is found that the proposed filter can reduce the common-mode noise from 0.5 to 1.2GHz over 10dB. But it occupies 94% less area compared to dumbbell-shaped DGS.