Tunable negative refractive index metamaterial phase shifter

A novel waveguiding ferrite phase shifter utilizing negative refractive index metamaterial is demonstrated, which is the first device application of negative refractive index metamaterial of its kind. The negative index metamaterial is positioned at middle of the waveguide along the longitude direction, which is composed by a periodic copper wire pattern sandwiched by two pieces of high quality yttrium iron garnet (YIG) films. At the high frequency side of the ferrimagnetic resonance (FMR), the YIG films provide the negative permeability while the copper wires provide the concomitant negative permittivity. The wave strongly interacts with the biased ferrite and the copper wires resulting in a large phase shift over a short distance. A phase shift tuning of 160deg/kOe is achieved at 24 GHz. The insertion loss varies from 4.4 dB to 6.3 dB for the 12 mm long sample.