Corrections to published information about atmospheric attenuation between 10 GHz and 1 THz

摘要

Atmospheric attenuation is one of the most significant factors in limiting the performance of millimeter-wave and terahertz systems. Although atmospheric propagation is fairly well understood up to 1 THz, major errors have been published in numerous locations showing atmospheric propagation at frequencies from 10 GHz to 1 THz. Some of these errors have been reported in the past by the present author. The topic was also reviewed in an invited plenary presentation by Bruce Wallace at the 2006 SPIE Defense and Security Symposium in Orlando. Several cases are discussed here, involving clear-air conditions, rain, and fog. In one example, the attenuation at 4 km elevation has been mislabeled as 9150 m (or 30,000 feet) for the 10 to 400 GHz range. This error has appeared in several journal articles, vendors' catalogs, short-course notes, and a recently-published book. In another case the attenuation peak near 22.3 GHz (due to water vapor absorption) has been plotted at 20 GHz. The third case deals with errors pertaining to attenuation in fog for frequencies between 10 and 1000 GHz. Specific information and corrections will be given for all three cases. The net result of these errors is that development of sensor and communications applications has been impeded because the errors usually make atmospheric losses appear to be greater than they really are.