On bandwidth of transmission-line-based and inclusion-based non-foster ENZ metamaterials

The bandwidth of recently introduced transmission-line-based and inclusion-based non-Foster active ENZ metamaterials is studied numerically and experimentally. It is shown that the inclusion-based non-Foster metamaterials exhibit narrower operating bandwidth (up to two octaves) comparing to the transmission-line-based non-Foster metamaterials (more than four octaves). This difference occurs due to frequency behavior of equivalent coupling network that connects neighboring unit cells.