Phase and amplitude dispersion for Earth-satellite propagation in the 20- to 30-GHz frequency range

Amplitude and phase dispersion have been measured for over a year on a 19- and 28-GHz earth-space propagation path. In the experiment amplitude and phase differences were compared for a 28-GHz carrier with±264-MHz sidebands and a 19-GHz carrier, all transmitted from a COMSTAR satellite. No dispersion (frequency selective fading) was found of the type caused by multipath propagation with a large spread in time delay or by resonances in the propagation medium. The only frequency dependences evident were due to the bulk properties of water in rain. The conclusion from this investigation is that amplitude and phase dispersion should not pose a problem for wideband (on the order of 1 GHz) satellite communication systems operating at frequencies greater than 10 GHz with elevation angles from the earth terminals of greater than15.