Millimeter-wave properties of the atmosphere: Laboratory studies and propagation modeling
Abstract
Laboratory measurements were performed at 138 GHz of water vapor attenuation alpha x for pure vapor (H2O) and its mixtures with air, nitrogen (H2), oxygen (O2), and Argon (Ar). A computer-controlled resonance spectrometer was employed. The results are interpreted in terms of underlying absorption mechanisms. A substantial amount of the self-broadening terms proportional to the square of vapor pressure is left unaccounted. The negative temperature coefficient of the excess absorption is consistent with a dimer (H2O2) model. An empirical formulation of the experimental findings is incorporated into the parametric propagation model MPM that utilizes a local (3ox H2), 48x O2) line base to address frequencies up to 1000 GHz. Details of MPM are given in two Appendices. Predictions of moist air attenuation and delay by means of the revised MPM program generally compare favorably with reported (10 to 430 GHz) data from both field and laboratory measurements.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- October 1987
- Bibcode:
- 1987STIN...8821387L
- Keywords:
-
- Atmospheric Models;
- Millimeter Waves;
- Predictions;
- Wave Propagation;
- Absorptivity;
- Attenuation;
- Dimers;
- Water Vapor;
- Communications and Radar