Exact radiation for slotted circular or elliptical antenna coated by a concentric isorefractive metamaterials

Exact solution to the electromagnetic radiation from a conducting slotted circular or elliptical cylinder coated by an Isorefractive metamaterials is derived by using the separation of variables technique. The fields inside and outside the dielectric layer are expressed in terms of Mathieu functions. No matrix inversion is required after obtaining expressions for the radiated field expansion coefficients by imposing the appropriate boundary conditions. Numerical results are plotted for the radiation pattern, aperture conductance and antenna gain. The results show that slotted antenna coated with Isorefractive metamaterials has more directive beam and lower side-lobes compared to that coated with conventional dielectric or metamaterials.