One embodiment of the invention sets forth a technique for using a resonator as a common-mode filter for attenuating unwanted common-mode frequencies in a differential signal. Filtering these unwanted frequencies may reduce electromagnetic interference from the differential signal pair in nearby electronic devices. Since common-mode filtering is employed, the resonator reduces the unwanted common-mode noise at specific frequencies without distorting the information-carrying differential signals. Further, since the filter is implemented as a PWB resonator, the incremental cost of including this filter on the PWB is relatively small.