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Cooling  down low noise amplifiers (LNAs) is a great way to reduce the thermal noise of the transistors that are used for amplification, however most cooling implementations are expensive for 24/7 operation and introduces thermal interfaces and trade-offs that affect noise performance negatively.

Miniature thermo-electric peltier modules, that are used to stabilize the temperature of high performance lasers for optical links, have a large ΔT and can be used to cool the chip directly when integrated in the LNA design.

This cooling implementation is more energy and cost efficient than cryogenic setups and can lower the noise contribution of the LNA to the receiver noise, increasing sensitivity of our radio telescopes with negligible power draw.

The image shows the latest prototype of an LNA, that uses the same indium phosphide transistors (pHEMTS) as the ALF project, with 'spot cooling' using a cooler of 1.5 x 1.8 mm.

It achieved an improvement in the minimum achieved noise temperature of 15% w.r.t. room temperature using only 1 Watt of cooling power, which is more than 200x as efficient per Kelvin as the MFFE cryostat.

We are investigating the possibilities to improve the heatsink for the thermo-electric cooler using microfluidics and Advanced Additive Manufacturing technology aiming at full integration with the horn antenna in an active OMT to bring down the noise below what is possible at room temperature.