Active tunable metamaterial transmission line based on lumped elements and negative differencial devices

To overcome the defects of metamaterials, such as high dispersion, the high loss, and the problem of homogenization, we design and implement an active tunable metamaterial transmission line, and measure the characteristics of active tunable metamaterial transmission line that is based on lumped elements and negative differential devices. From the measured results, it exhibits not only electronically tunable scattering parameters (electro-control tunable characteristic) but also the negative attenuation constant (the propagation amplification) in the left-handed frequency band (active characteristic).