Superdirective antennas with passive reflectors

A brief introduction to the problem of superdirective radiation in antenna theory, and a solution to the problem of wave scattering from a structure, formed by resonant scatterers, is presented. The paper describes construction of a two-dimensional superdirective antenna with one active element, and a reflector made of resonant scatterers-unclosed cylinders proposed by Veremey and Shestopalov (see Radio Science, vol.26, no.2, p. 631-636, 1991). Physical phenomena, which cause the effect of superdirective radiation, are studied in detail. It is shown that the interaction between the resonant elements leads to the possibility of exciting a mode characterized by a high level of reactive power, in the vicinity of a passive structure. Particular attention is paid to the sensitivity of the superdirective antenna, and to tolerance constraints. It is shown that changes of the angular width of a slot in an unclosed cylinder (or in several unclosed cylinders), within ±1%, do not lead to the destruction of the superdirective resonance