1、Rec. ITU-R BO.1296 1RECOMMENDATION ITU-R BO.1296REFERENCE RECEIVE SPACE STATION ANTENNA PATTERNS FOR PLANNINGPURPOSES TO BE USED FOR ELLIPTICAL BEAMS IN THE REVISION OFTHE APPENDIX 30A (Orb-88) PLANS OF THE RADIO REGULATIONSAT 14 GHz AND 17 GHz IN REGIONS 1 AND 3(Question ITU-R 218/11)(1997)Rec. ITU
2、-R BO.1296The ITU Radiocommunication Assembly,consideringa) that Resolution 531 (WRC-95) (World Radiocommunication Conference (Geneva, 1995) invites the ITU-R tostudy the possibilities to improve the efficiency of the Appendix 30A (Orb-88) Plans of the Radio Regulations (RR) bytaking due account of
3、the technological progress;b) that for the feeder link of the broadcasting-satellite service planning purposes a simple receive space stationantenna reference pattern is necessary;c) that the existing RR Appendix 30A (Orb-88) Regions 1 and 3 receive space station antenna patterns are nolonger approp
4、riate due to technological improvements;d) that measured data in support of an improved receive antenna reference pattern is available;e) that the use of antennas with the best achievable radiation pattern will lead to the most efficient use of theradio-spectrum and the geostationary-satellite orbit
5、,recognizing1 that the adoption of improved reference receive space station antenna patterns for planning purposes does notprevent the use of other antennas that have been coordinated or will be coordinated in the future on the basis of differentpatterns;2 that these patterns may become part of the
6、Plan,recommends1 the use of the circularly polarized reference antenna co-polar and cross-polar patterns given in Fig. 1 togetherwith their associated formulae provided in Annex 1, for elliptical beams for planning purposes in the revision ofthe RR Appendix 30A (Orb-88) Plans in Regions 1 and 3.2 Re
7、c. ITU-R BO.12961296-010 10 20 30 405011010210125 2525FIGURE 1Receiving space station circularly polarized antenna co-polar andcross-polar reference patterns for elliptical beamsRelativegain(dB)Relative angle, /0Curves A: new receive space station Co-polar (same as Curve A*, Fig.B,RR Appendix 30A (O
8、rb-88) Regions 1 and 3)B: new receive space station cross-polarC: curve C (minus the on-axis gain)B*: Fig.B, RR Appendix 30A (Orb-88), Regions 1 and 3, cross-polar* Curves included for information only.A and ABBCFIGURE 11296-01 = 17 cmANNEX 1Formulae associated to the curves of Fig. 1Curve A: co-pol
9、ar relative gain (dB):G = 12 (/0)2for 0 /0 1.3G = 17.5 25 log (/0) for 1.3 /0After intersection with Curve C, as Curve C.Rec. ITU-R BO.1296 3Curve B: cross-polar relative gain (dB):G = 35 for 0 /0 1.75G = 40 40 log (/0 1) for 1.75 /0After intersection with Curve C, as Curve C.Curve C: minus the on-a
10、xis gain (Curve C in the above figure illustrates the particular case of an antenna with anon-axis gain of 44.44 dBi),where: : off-axis angle (degrees)0: cross-sectional half-power beamwidth in the direction of interest (degrees).The relationship between the maximum gain of an antenna and the half-power beamwidth can be derived from theexpression:Gmax(dB) = 44.44 10 log a 10 log bwhere a and b are the angles (degrees) subtended at the satellite by the major and minor axes of the ellipticalcross-section of the beam.
