A finite element thermal simulation of a microwave blackbody calibration target

摘要

We introduce a method to determine the gradient between measured physical temperature and true radiating surface temperature of a passive microwave calibration target (load or blackbody). An empirical cooling-curve fit is employed to determine heat-transfer coefficients that then allow commercial finite-element software to solve for the physical temperature at the surface of the target. Only gradients in the direction parallel to the target's pyramidal structures are determined. Two target insulation thicknesses are investigated and a mean surface radiating temperature is determined. This surface temperature differs from the internally measured physical temperature by a maximum of 0.3 K in an ambient environment. Use of a thicker insulation assembly decreases this temperature bias by 0.1 K.