Ka band system and propagation effects on system performance

Abstract

Abstract-The Advanced Communication Technology Satellite (ACTS) is an experimental communications satellite system launched in September 1993. ACTS introduces many new technologies, including operation in the Ka frequency band. ACTS uses multiple hopping narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for a bit-error-rates of 5x10 -7 or better over the continental United States. In order to maintain a minimum system availability of 99.5% over all US rain zones ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of system and sub-system characterization considering the statistical effects of system variances due to thermal and propagation effects over 6 years of ACTS operation including inclined orbit.

Channel Attenuation Models over Ka Band Satellite Systems at Venezuelan Amazonian Area

“…The attenuation model mostly depend of frequency, geographic location and elevation angle [5]. For elevation angles bigger than 10 degree, only Attenuation by atmospheric gases, Attenuation by rain and possibly Scintillation and multipath effects, could be considered [9], the rest of the losses can be neglected.…”

“…The ITU-R methods, are normally used in satellite circuits to find the fade margin that must be included in the link budget. Rain attenuation mainly depends on: frequency, location, polarization and rainfall rate [1,2,3,5,6]. The depth of attenuation in decibels for the Venezuelan location can be calculated from: The rainfall rate "R", for a 0.1% of excess rain, mean a 99.9% of service availability.…”

“…The demand in satellite communications services increases in an exponential way, for that reason the lower bands as C and Ku are saturated of users [5]. Thus the Ka-band is suitable in order to install several applications.…”