Antenna Diversity in the Presence of Multipath Fading at 6 GHz

Multipath fading is of particular concern in digital radio systems because of the effects of a dispersive channel on the digital signal. Independent microwave monitoring experiments are presently being conducted at both ends of a 6 GHz radio hop in Southern California. The microwave path crosses irrigated land and desert and is plagued by multipath phenomena. Fade depth and dispersion data are being collected in real time using three equally spaced filters within a 22 MHz channel. The data are analyzed in order to characterize the time dynamics of dispersive fades. Long term statistics of fade depth and in-band power differences are also being collected. The measurements are made for unprotected, space diversity, and angle diversity antenna configurations at both ends of the hop. Time below level plots of single tone fade and in-band power difference are shown for the three antenna configurations at each receiving station in order to characterize the long-term behavior of each antenna system in the presence of fading.