Effect of a shielding plane connected to ground plane of a PCB in EMI reduction

Effect of a shielding plane used for suppressing emission from a PCB is experimentally studied in this paper. The shielding plane is connected to some points of a ground plane contained in the PCB. In many cases of products, cables extend out of the shielding area and signal traces exist outside of this area. These cables and signal traces cancel the effect of shielding the devices inside of the shielding area. Moreover, in these cases, an extended shielding plane increases radiation level from the PCB.