Statistical processing method for sidelobe peaks for earth-station antennas

For coordination studies and for the assessment of mutual interference between radiocommunication-satellite systems and between earth stations and radio-relay stations sharing the same frequency band, the method which represents off-axis radiation characteristics of the earth-station antenna is desirable. For this purpose, International Radio Consultative Committee (CCIR) Report 391-4 describes a statistical processing method of sidelobe peaks which was adopted at the XVth Plenary Assembly in 1982. This statistical processing method is based on the slope of reference radiation pattern, while the old one, which has been used, is based on the absolute peak value. Therefore, the results of the statistical evaluation using the current (new) method may differ from that using the old method. According to the measured data on a Cassegrain antenna of 13 m in diameter at about 12 GHz, it is shown that the worst 10 percent value of sidelobe peaks of the new processing method, which is the level exceeded by 10 percent of the peaks, is statistically about 0.8 dB lower than that of the old method.