Hans J. Liebe

Abstract: This report describes a laboratory experiment which was conducted to find out if the absolute attenuation of a 35 GHz signal by the molecular species H₂O₂ (hydrogen peroxide), HNO₃ (nitric acid), NO₂ (nitrogen dioxide), N₂O (nitrous oxide) exceeds a threshold value of 0.2 dB/km for concentrations reaching 500 ppm/vol in 1 atm of air. A resonance spectrometer was operated with a detection sensitivity of 0.1 dB/km to obtain pressure scans of attenuation and refraction for the pure gases at low pressures (< 1 kPa) and for binary mixtures at atmospheric pressures (> 50 kPa) using nitrogen as the inert, loss–free host gas. Model calculations of attenuation over the frequency range 10 to 50 GHz were performed for natural moist air and hot air (< 500 K) under sea level conditions. The measurements of the identified trace gas species produced little (< 0.2 dB/km) additional attenuation.

Keywords: atmospheric attenuation; laboratory measurements; model calculations; trace gas absorption; 3.5 GHz band; sea level conditions

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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.

Back to Search Results