The study of PCB ground area and location on EMI reduction effectiveness

The ground technique is often proposed for suppressing and controlling the noise of EMI emissions. The signal grounds are defined as a low-impedance path for current flowing into the source which can be divided into different modes of ground plane. Nowadays, all the electronic products have already intend to the smaller and thinner size, therefore, the area of ground on PCB will be limited. The R&D and EMI engineers have to face the less and less ground plane which can be utilized. In this paper, the EMI reduction effectiveness for the area of ground plane and location on the PCB is studied by radiated measurement results. The coupling behaviors of the electric or magnetic fields between the traces of harmonic signal and ground plane are investigated to suppress the EMI interferences. The main contributions of this work are the experimental verification and analysis that can be used for the EMI reduction effectiveness. The area of ground plane and location will determine the effectiveness of capacitive coupling and return currents path. The designer can use this concept to achieve the best EMI performance with limited PCB ground plane.