Zero loss magnetic metamaterials using powered active unit cells

Zero loss magnetic metamaterials using powered active unit cells.

We report the design and experimental measurement of a powered active magnetic metamaterial with tunable permeability. The unit cell is based on the combination of an embedded radiofrequency amplifier and a tunable phase shifter, which together control the response of the medium. The measurements show that a negative permeability metamaterial with zero loss or even gain can be achieved through ...

Microstrip Antenna Gain Enhancement using Near Zero Refractive Index Metamaterials

Some useful features of microstrip patch antennas are low profile, low weight and easy fabrication. However this type of antenna suffers from having a low gain, caused by propagation surface waves. In this paper, a new near zero refractive index metamaterial (MTM) unit cell is designed and fabricated as a superstrate over a Rectangular Microstrip Patch Antennas (RMPA). In order to obtain a maxi...

Active Magnetic Bearing Control with Zero Steady-State Power Loss

In this paper, we address the problem of controlling an active magnetic bearing with reduced ohmic power losses. A solution is proposed which introduces an exponentially decaying bias ßux in the nonlinear control law. To avoid control singularities, the closed-loop system is exponentially stabilized at a faster rate than the bias decay. In the steady state, the proposed controller has zero bias...

Loss-compensated and active hyperbolic metamaterials.

We have studied the dispersion relations of multilayers of silver and a dye-doped dielectric using four methods: standard effective-medium theory (EMT), nonlocal-effect-corrected EMT, nonlinear equations based on the eigenmode method, and a spatial harmonic analysis method. We compare the validity of these methods and show that metallic losses can be greatly compensated by saturated gain. Two r...

Loss-compensated broadband epsilon-near-zero metamaterials with gain media