Mathematical model of generalized radiation patterns of point-to-point and point-to-multipoint fixed service antennas for use in statistical interference assessment

Many of the satellite frequency allocations are based on the principle of sharing between terrestrial and space applications. To protect one sharing service from another, upper limits have been established by the ITU (International Telecommunication Union) on the amount of rf power that can be present at and interfere with a receiving station. To calculate the interference level at the fixed service (FS) receiver due to the broadcasting satellite service (BSS), antenna gain and sidelobe levels are the major factors to be determined. ITU Recommendation F.699-4 has suggested the maximum allowable gain and the side-lobe levels as a reference for antenna radiation patterns; however, this model overestimates the interference level. In a recent revised ITU model (ITU Recommendation CG9/6 Rev. 2-E), a more realistic reference antenna pattern has been proposed but in some cases it underestimates the interference levels. In this paper, a new model for generalized antenna radiation patterns is proposed using variable boundaries dependent on the antenna parameters.