Abstract
The Noise Project in the Electromagnetics Division of the National Institute of Standards and Technology (NIST) is developing standards for microwave brightness temperature (TB) for use in remote-sensing applications such as satellite-based weather observations. We have recently demonstrated a TB standard consisting of a NIST radiometer traceable to fundamental standards combined with an antenna, which is then used to measure the apparent brightness temperature of a black body calibration target. The initial measurements, performed in the 18 to 26.5 GHz (WR-42) band, lead to a TB uncertainty of about 0.7 to 1 kelvin. Complementary to the standard radiometer work is a new method for characterizing the target’s reflectivity, which is closely associated with emissivity. The technique involves a vector network analyzer calibration in free space, which is then used to measure the target reflectivity with full uncertainty statement. NIST is also working on a black body target TB standard and a high-frequency (110 to 500 GHz) antenna range, among other topics. Latest developments in these areas will be reported in the talk.
SI-Traceable Microwave TB Standards Development at NIST
The Noise Project in the Electromagnetics Division of the National Institute of Standards and Technology (NIST) is developing standards for microwave brightness temperature (TB) for use in remote-sensing applications such as satellite-based weather observations. We have recently demonstrated a TB standard consisting of a NIST radiometer traceable to fundamental standards combined with an antenna, which is then used to measure the apparent brightness temperature of a black body calibration target. The initial measurements, performed in the 18 to 26.5 GHz (WR-42) band, lead to a TB uncertainty of about 0.7 to 1 kelvin. Complementary to the standard radiometer work is a new method for characterizing the target’s reflectivity, which is closely associated with emissivity. The technique involves a vector network analyzer calibration in free space, which is then used to measure the target reflectivity with full uncertainty statement. NIST is also working on a black body target TB standard and a high-frequency (110 to 500 GHz) antenna range, among other topics. Latest developments in these areas will be reported in the talk.