LOCALIZED LNA COOLING IN VACUUM

In the Square Kilometre Array (SKA) telescope [1], [2], the noise temperature of the first LNA must be redu ced in order to reduce the necessary active area and the t otal system costs. Cooling the LNA locally would significantly decrease the noise figure but also the necessary power since not the whole system has to be cooled. For optimal thermal isolation, an LNA chip which only needs 6 bondwires has been chosen, 4 Ground and 2 signal wires. Biasing occurs on-chip. If the bondwi res are 1.5mm long, the total heat conduction of the 6 bond wires is 31 mW, which is added to the power consumption of the LNA (30 mW). With a power of 61 mW to cool, the