A1 Refereed original research article in a scientific journal
Uncertainty of Radiometer Calibration Loads and Its Impact on Radiometric Measurements
Authors: Matti Kaisti, Miikka Altti, and Torsti Poutanen
Publisher: IEEE
Publication year: 2014
Journal: IEEE Transactions on Microwave Theory and Techniques
Journal acronym: MTT
Volume: 62
Issue: 10
First page : 2435
Last page: 2446
Number of pages: 12
ISSN: 0018-9480
DOI: https://doi.org/10.1109/TMTT.2014.2349873
Web address : http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6895175
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/1993438
We present an uncertainty analysis of radiometer calibration.
The procedure can be used to determine the uncertainty
in the nominal brightness temperature of the unknown scene. A
total power radiometer requires frequent calibration with known
reference loads that are connected to the radiometer. Our analysis
includes uncertainties from the radiometer calibration loads and
from the connecting network (CN) that is required to multiplex
calibration loads and scene to the radiometer input. We show the
design and analysis of three calibration loads and how their uncertainties
propagate from load terminals to the radiometer calibration
plane and to the scene. All three loads, including a cryogenic
load, are simple, inexpensive, and show great stability and
accuracy. We give an uncertainty calculation example for our three
calibration loads and for the CN. We validate our model and the
long-term stability of the loads through measurements. The analysis
is done at 52 GHz, but the analysis and the construction of the
loads are generic and easily scalable to other frequencies.
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