Thermal profile measurements of a Luneberg lens

A Luneberg lens provides a low profile antenna design for 20 and 44 GHz BLOS communications on an aircraft. Measurements and analyses have been performed to quantify the thermal profile that a polystyrene Luneberg lens would experience when exposed to radiation at 44 GHz. Polystyrene, an excellent thermal insulator, is cured at a low temperature and could potentially experience permanent physical deformation after the lens has been "soaked" of temperature levels greater than 180°F (82°C). Not only must the antenna system operate while exposed to ambient surrounding temperatures up to 63°C to 71°C but it also must be able to accept additional RF heat loads due to radiation from the feed. This work includes the analyses and measurements of the lens thermal response and profile during operation at 44 GHz. The lens construction is defined and the test methodology outlined. Measurements and analyses are presented and compared. This information could be utilized for extrapolation to predict the thermal profile as a function of input thermal load that would be observed under potential operational conditions and environments.