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Microwave radiometer for subsurface temperature measurementA UHF radiometer, operating at a frequency of 800 MHz, was modified to provide an integral, three frequency voltage standing wave ratio (VSWR) circuit in the radio frequency (RF) head. The VSWR circuit provides readings of power transmission at the antenna-material interface with an accuracy of plus or minus 5 percent. The power transmission readings are numerically equal to the emissivity of the material under observation. Knowledge of material emissivity is useful in the interpretation of subsurface apparent temperatures obtained on phantom models of biological tissue. The emissivities of phantom models consisting of lean beefsteak were found to lie in the range 0.623 to 0.779, depending on moisture content. Radiometric measurements performed on instrumented phantoms showed that the radiometer was capable of sensing small temperature changes occurring at depths of at least 19 to 30 mm. This is consistent with previously generated data which showed that the radiometer could sense temperatures at a depth of 38 mm.
Document ID
19770017513
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Porter, R. A. (Radiometric Technology, Inc. Wakefield, MA, United States)
Bechis, K. P. (Radiometric Technology, Inc. Wakefield, MA, United States)
Date Acquired
September 3, 2013
Publication Date
May 1, 1976
Subject Category
Instrumentation And Photography
Report/Patent Number
NASA-CR-137827
Accession Number
77N24457
Funding Number(s)
CONTRACT_GRANT: NAS2-8337
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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