Ya. S. Shifrin

Factors that stimulated creation of the statistical antenna theory (SAT) at the beginning of the sixties of the last century are discussed. Considered as such are: a) the necessity of the statistical tolerances theory development; b) a problem of generalization for the statistical theory of focusing system diffraction images; c) a problem of the analysis and adequate performance interpretation for the antenna working in the field of long-distance tropospheric radio wave propagation. It is noted that these three problems under solution each necessitated building a rather general theory of the randomness influence of antenna performance at arbitrary randomness parameters. Along with this, already at the initial stage, the significant difference in these problems allowed to a considerable degree judging about the possibilities of the SAT under development, and a circle of problems being possible to be solved with its help. Further, SAT peculiarities, its distinctions from the deterministic (ordinary) antenna theory are analyzed. It is noted that in SAT, a number of habitual concepts of the ordinary theory need to be corrected and redefined. New notions and new effects inherent in SAT have appeared. Considered among the latter are a) the limiting directive gain and minimum attainable wave length in reflector antennas; b) limitations imposed on large antennas directive gains by the atmosphere inhomogeneities; c) the minimum attainable side radiation level; and d) transformation of the superdirectivity effect in SAT. All these effects, as well as other SAT results, show that the sources fluctuations, being unavoidably present in antennas, introduce significant corrections in the results of the ordinary antenna theory. Therefore, it is not by chance that for the last decades, consideration of SAT results has become an obligatory component when designing, developing and exploiting large expensive antenna systems.