March 1991 | Data

Attenuation and Delay Rates of Dry Air at V-band frequencies (50–75 GHz)

Hans J. Liebe, George A. Hufford, and Robert O. DeBolt

Abstract:

NTIA Technical Report TR-91-272, March 1991, describes measurements taken during an experiment to confirm modeled attenuation and delay rates of dry air throughout the V-band (50–75 GHz). Over 4,000 attenuation values are reported for measurements between 53.9 and 66.3 GHz in 0.1 GHz frequency increments at eleven pressure steps (1–100 kPa) for three temperatures (7, 30, 52 °C). These measurements constitute a unique data set with respect to their comprehensive extent in pressure, temperature, and frequency.

The file LIEBE_DATA.ZIP contains a description of the file format and multiple ascii files, each containing measurements of absorption in synthetic air at one temperature and pressure. Each file is in ascii (DOS or Windows format) and contains measurements of absorption in synthetic air at one temperature and pressure, from which the file name is constructed: e.g., 06H18.DAT contains data at 6 C and pressure equivalent to 18 km in the U.S. standard atmosphere. The composition of the test air was 20.45% O2, 79.55% N2, 2.1 ppm H2O, <1 ppm CO2, <1 ppm total hydrocarbon.

The experiment and its interpretation in terms of a model (MPM92) are described by H. J. Liebe et al., J. Quant. Spectros. Radiat. Transfer Vol. 48 (5/6), pp. 629–643, 1992.

The data can be thought of as an NxM matrix, where N is the number of measurement frequencies and M=6. The first line of each file contains N, M, Pressure (millibar), temperature (kelvin), separated by commas.

The next N lines contain 6 values, separated by commas:

  1. data(i,4) = Frequency(Ghz)
  2. data(i,5) = Absorption coefficient in test air (dB/km)
  3. data(i,6) = Standard deviation (dB/km)
  4. data(i,1-3) = Frequency, Absorption, Standard deviation for the vacuum baseline.

Keywords: attenuation; laboratory measurements; atmospheric oxygen spectrum; dry air; parametric studies

Related Links:

LIEBE_DATA.zip

For questions or information on this or any other NTIA scientific publication, contact the ITS Publications Office at ITSinfo@ntia.gov or 303-497-3572.

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