The relationship between S21 properties and far-field radiated emission has been experimentally characterized for various types of power bus structures. As design parameters of power bus structures in printed circuit boards, the effects of VDD plane configuration, insulator thickness between VDD plane and ground plane, on-board capacitors, and signal routing were investigated. First, S21 properties of solid and electromagnetic band-gap (EBG)-type VDD planes were measured for both with and without on-board capacitors. Then, far-field radiated emission was measured for the combination of these design parameters. On-board capacitors induced stop-band in the low frequency range. It has been found that high level of far-field radiated emission was excited at the almost same frequencies of S21 peaks.