Abstract: A new type of flip-line coplanar electromagnetic band-gap (EBG) power supply layer structure was proposed in this paper, and the SSN suppression characteristic simulation analysis and practical application test were carried out. Maintaining the metal connection line gap width of 0.2 mm unchanged, four coplanar EBG power supply layer structures were designed with the design width of 0.1, 0.2, 0.3, 0.4 mm respectively. The simulation results show that the cutoff frequency of the coplanar EBG power supply layer with the width of 0.2 mm is the lowest, and the relative band width is higher and the relative characteristic is the best. A coplanar EBG power supply layer with a metal cable width of 0.2 mm was used to fabricate a PCB based on the printed circuit board process. And the actual test was carried out by the vector network analyzer (VNA). The suppression characteristic curve obtained is basically consistent with the trend of the simulation curve, verifying the validity of the design.