Ferrite-covered open stub as lossy resonator filter for suppressing noise propagation in power bus

A lossy resonator filter with frequency selectivity and low loss, which suppresses noise propagation in the power-ground plane pair of a printed circuit board (PCB) at high frequencies (over 1 GHz), was fabricated and evaluated. A ferrite-covered open stub was formed on a PCB as a lossy resonator filter, and its characteristics were verified by measurement using a vector network analyzer as well as full-wave simulation. The measurement and simulation results show that the noise in the power bus of the PCB at frequencies over 1 GHz is suppressed. Even in the case that the power bus is inside the board, noise propagation in the power bus was suppressed by connecting the inside ground plane and the ground plane of the lossy resonator filter by vias in order to conduct the noise to the filter.