Cloud attenuation modelling for SHF and EHF applications

Abstract

SUMMARYTropospheric propagation impairments that a!ect earth}space communication signals increase in severity with the increase of frequency. Introduction of satellite services using higher frequency bands such as Kaand V-band requires the characterization of propagation factors that are normally considered negligible at lower frequency bands. Cloud attenuation is considered one such factor. Clouds are present during a large fraction of an average year and cloud attenuation, together with gaseous absorption, will determine the system performance under non-rainy conditions. A cloud attenuation model that has global applicability is presented in this paper. The model is based on average properties of four cloud types and their occurrence probabilities. The occurrence probabilities are derived from long-term observations of cloud cover carried out by several thousand meteorological stations throughout the world. Predictions made with the model are compared with cloud attenuation data gathered using Ka-band beacon signals and radiometers.

Simulation of discrete electromagnetic propagation model for atmospheric effects on mobile communication

“…Cloud attenuation depends on frequency, liquid water content of the cloud, elevation angle, types of the cloud, shape and size of the cloud, cloud base height, and the present weather. Moreover, attenuation increases as temperature decreases [7]. Since cloud attenuation depends on many factors that are hard to observe and identify or classify, modeling of cloud attenuation is relatively more complex.…”

Cloud Attenuation in Millimeter Wave and Microwave Frequencies for Satellite Applications over Equatorial Climate

“…Ice clouds, by virtue of the low dielectric constant of ice and the small size of the constituent particles, are not expected to cause appreciable attenuation to radiowaves in the frequency range below 50 GHz [2]. It has been reported by researchers [5] that clouds density and concentration varies from 0.15 g/m 3 to 1 g/m 3 and 70 per cm 3 to 450 per cm 3 , respectively.…”

“…However, many projected Ka-band and V-band services uses small terminals and, for these, rain effects may only form a relatively small part of the total propagation link margin. But cloud attenuation, that may cause deep fades in these band, is one of the components that need to be considered for low availability satellite links owing to its higher probability of occurrence [1,2]. A number of experimental studies of atmospheric attenuation at millimeter wave have been conducted.…”

Cloud Attenuation for Satellite Applications Over Equatorial Climate

“…Ice clouds, by virtue of the low dielectric constant of ice and the small size of the constituent particles, are not expected to cause appreciable attenuation to radiowaves in the frequency range below 50 GHz [2]. It has been reported by researchers [5] that clouds density and concentration varies from 0.15 to 1…”