Miniaturized circular waveguide probe antennas using ENNZ metamaterial liners

This paper investigates the miniaturization of circular open-ended waveguide (OEWG) probe antennas by lining their interior with thin epsilon-negative-and-near-zero (ENNZ) metamaterial liners. Comparisons are drawn between the radiation characteristics of the miniaturized and conventional-sized OEWG probes, focusing on their return loss, far-field patterns, and radiation efficiency.