Radiation from an axially slotted antenna coated with eccentric layer of inhomogeneous medium embedded in metamaterial

Abstract The gain properties of an axially slotted cylindrical antenna coated with eccentric layer of inhomogeneous material placed in different metamaterials have been investigated. The slot is assumed to be infinitesimally thin such that it can excite TE mode only. The radiated fields in region filled by inhomogeneous material are written in terms of modified Bessel and Hankel functions of non-integer order and the eccentricity is mathematically incorporated by employing Graf’s addition theorem. Numerical results to describe the radiation characteristics of antenna are presented and discussed while taking different profiles for the inhomogeneity, values of the eccentricity parameter, operating frequency, and type of host medium. It is observed that the radiation pattern can be controlled, from isotropic (omnidirectional) to directive one, by selecting suitable choice of the inhomogeneity profile and value of the eccentricity parameter. Another interesting feature of the antenna is found when it is embedded in zero index medium, in that case the exponent of the profile function ψ ( κ ρ ) has direct relationship with the number of main lobes in the radiation pattern.