To build a stable power distribution network for high-speed digital systems, simultaneous switching noise (SSN) should be sufficiently suppressed in multi-layer PCBs. In this paper, novel uni-planar compact electromagnetic bandgap (UC-EBG) structures with triangular-type unit cells designed on power/ground planes are proposed for the ultra-broadband suppression of SSN. The effect of the structural parameters on the EBG bandgap changing their parameter values is investigated. The SSN suppression performance of the proposed structure is validated both numerically and experimentally. A -30 dB suppression bandwidth for SSN is achieved, starting at 830 MHz and extending to 15 GHz and beyond, thereby covering almost the entire noise band.