Simulations to characterize a passive microwave blackbody design

This paper discusses the design of a microwave blackbody to be used as a primary laboratory standard for passive remote sensing applications. This temperature adjustable design is required to operate and be fully characterized from 10 to 220 GHz. We discuss the challenges involved in designing this type of calibration source and address how improvements can be made to increase performance over blackbodies typically flown on airborne and space-borne instruments. A simplified electromagnetic model for absorber layer optimization is introduced as the precursor to a finite-element, full-wave solution for the calculation of emissivity. A temperature simulation predicts the physical temperature of the blackbody and surrounding chamber. The simulated data are used as inputs to a rigorous calculation of the microwave brightness temperature radiated by the blackbody source. This calculation provides an estimate of the offset between measured physical temperature and radiometrically measured brightness temperature.