An electronic device including a sealed enclosure, the electronic components arranged inside the sealed enclosure and including high-loss high-temperature components, a main heat sink including ribs, wherein the high-loss high-temperature components are attached to the main heat sink and the ribs of the main heat sink are arranged outside the enclosure, a cavity formed inside the enclosure and divided into a plurality of channel-like sections, the channel-like sections configured for providing air flow guidance inside the enclosure and being interconnected at their ends, wherein at least one channel-like section contains the electronic components and at least one other channel-like section contains an air-to-air heat exchanger extending from inside the sealed enclosure to outside of the sealed enclosure, wherein the electronic components inside the at least one channel like section are adapted to be cooled by air flow inside the sealed enclosure.