There is provided a heat dissipation device comprising at least one inlet plenum, at least one outlet plenum and chambers, in which the chambers communicate directly with the inlet plenum and with the outlet plenum. Also provided is a heat dissipation device comprising at least two inlet plenums, at least two outlet plenums and at least two chambers, the first chamber communicating directly with a first inlet plenum and a first outlet plenum, the second chamber communicating directly with a second inlet plenum and a second outlet plenum. Also provided are methods of dissipating heat, comprising passing fluid across and/or through such devices. Also provided are radar antennas comprising radar electronic components mounted on such devices.