Design of a metamaterial circular patch antenna loaded with an ε-negative core

In this paper, a circular patch antenna filled with a metamaterial epsilon-negative (ENG) core is presented and thoroughly studied. The proposed structure is initially designed and numerically tested for a core of a theoretically continuous isotropic material, which exhibits an ENG behavior, in order to add extra resonances. Then, the desired ENG core is realized using a set of properly devised and placed metamaterial electrical resonators to achieve an equivalent anisotropic medium that supports negative ε^´ values for the desired field modes. Comparisons between theoretical and practical implementations reveal a satisfactory agreement, thus indicating possible applications like miniaturized antennas, dual-band radiators and testing devices.