Accuracy improvement of approximate noise temperature calculations of offset Gregorian reflector systems

Calculation of the antenna noise temperature for an offset Gregorian reflector system is computationally intensive. The main reflector masking technique, where the main reflector is removed from the calculation domain, considerably reduces the computation cost. This technique, however, is less accurate for electrically smaller systems. Recently an improvement to the technique was proposed by introducing a diffraction compensated correction factor. In this case the error on receiving sensitivity can be in the order of a few percent. This paper further improves on the technique by introducing a power dependence to the inverse frequency diffraction compensation. The technique reduces the error of the receiving sensitivity to well below a percent.