Epsilon-Zero Resonance Antennas with Modified Unit Cells

In this paper new epsilon-zero resonance (EZR) antennas using epsilon negative (ENG) transmission line (TL) are presented. In the proposed antennas, the unit cell of the ENG TL is implemented using a modified mushroom-like structure in which the via hole is placed at the patch edge. This configuration leads to a broadside radiation pattern and also results in the unit cell size reduction. These antennas are analyzed using transmission line based metamaterials and zeroth order resonators (ZORs) theories. A one unit cell compact size antenna and a nine unit cell high gain antenna using this new configuration are designed and fabricated. The measurement results including radiation pattern, maximum gain and return loss show good agreement with simulation results.