An analysis about the effects of various bi-isotropic (BI) coatings and BI background media upon the gain characteristics of an axially slotted cylinder using numerical simulations is presented. It is investigated that chirality and Tellegen parameters of a coating and a background medium play a significant role in modifying the gain properties. It is further studied that an axially slotted cylinder when coated with a strong BI material and embedded in a free space background significantly enhances the gain in the forward direction. On the other hand, a strong Tellegen coating guides most of the radiated field from an axial slot toward rear side of the cylinder.
