According to the invention, an electromagnetic radiation shielding cap is located over an electronic cartridge substrate. The electromagnetic radiation shielding cap includes an electromagnetic radiation shielding plate and an electromagnetic radiation shielding rim extending around a periphery of the electronic cartridge substrate. An edge of the electromagnetic radiation shielding rim contacts a thermally and electrically conductive heat plate located on an opposing side of the electronic cartridge substrate. The heat plate and the electromagnetic radiation shielding cap jointly define an electromagnetic radiation shielding enclosure around the electronic cartridge substrate.