In this article, the Signal Integrity performance analysis of mutual coupling reduction with defective ground structures (DGS) in high speed PCBs has been investigated. The performances of these structures are analyzed, in terms of Time domain, Error Vector Magnitude (EVM), eye pattern and timing jitter. A NRZ test signal with Quadrature Phase Shift keying modulation, with a carrier frequency of 3.5 GHz is used for the EVM measurements. From the EVM measurements, it is observed that the PCB with Circular DGS has the lowest EVM of 1.195 % rms compared to other techniques. Further, the eye pattern and jitter analysis show that the circular DGS has the lowest jitter value of 8 ps at 1Gbps data rate. Finally, the electromagnetic compatibility of proposed method is checked with the surface current distribution and radiated emission analysis. These investigations show that the adoption of the circular DGS in the high speed PCB design, reduces the spacing between two traces without degrading the signal quality. © 2016, Springer Science+Business Media New York.