Radiation mechanism and solution of cable attached differential signals

A common-mode radiation problem induced by cable-attached structure will be discussed and simulated. We will focus on how a cable-attached structure radiates, and how its victim, a Wi-Fi antenna, is affected. Mechanism of common-mode radiation will be showed, and verified by simulated results. Also, a solution using a common-mode filter (CMF) will be proposed, and it will largely suppressed the common-mode radiation from the cable-attached structure. To be more practical, PRBS signals with 212 bit stream are inserted into the system, and the signals received by the Wi-Fi antenna will show that the voltage spectrums in frequency domain are well-suppressed around 2.4 GHz. It proves the usefulness of the CMF.