Statistical Gain Characteristics of Radar Antennas at Very Short Fresnel Zone Distances

This paper extends the existing knowledge of statistical gain characteristics of radar antennas to include very short Fresnel zone ranges. The data indicate that the median gain and the standard deviation remain essentially the same as those observed in the Fraunhofer zone until the range begins to approach the physical dimensions of the antenna; however, as the range is decreased closer toward physical contact, the median gain decreases and the standard deviation increases. The site-effects tests which were conducted in the Fresnel zone indicate that the geometrical configuration of an object, the position of an object, and the clear-site median gain of an antenna help to determine the magnitude of the effects of objects on the clear-site statistical gain characteristics.