D.D. Gabrielyan, A.A. Ilatovsky, R.N. Korsun, V.M. Musinov, D.S. Fedorov
Using of special covers produced from magnetodielectric or metamaterials is one of the most interesting problem in antenna theory and important sphere from point of view of practical applications. Presence of such materials layer can lead to considerable changes on directivity characteristics of electric (dipoles) and magnetic (microstrip antennas, open waveguides) type of radiators.
Wide using of these effects in practice is restricted, because these materials are very complex and expensive. At the same time executed theoretical researches don´t allow to establish regularities of how parameters of magnetodielectric or metamaterial cover influence to antenna directivity characteristics.
In this paper the specified researches are spent for longitudinal slot on surface of ideal PEC circular cylinder covered by layer of magnetodielectric. The values of relative permittivity and permeability are more and less than one (the permeability of free space). Within the limits of strict model the received decision defines in analytical form interrelation of slot radiator directivity characteristics with parameters of magnetodielectric cover. The dispersive equation which defines a condition of occurrence of surface waves is received.
It is noticed, when the optical coefficient of refraction is more than one, magnetodielectric cover gets waveguide properties. This leads to occurrence of radiation pattern oscillations. Otherwise narrowing of considered radiator radiation pattern is observed. Physical interpretation of noticed effects based on geometrooptical method is offered for explanation arising regularities.
These regularities can be used in practice for expansion of variation antenna systems directivity characteristics possibilities, in particular receive narrower radiation pattern that allows rising of space selective properties of antenna system.