Journal of Magnetism and Magnetic Mat at e

A magnetic field tunable, broadband, low-loss, negative refractive index metamaterial is fabricated using yttrium iron garnet (YIG) and a periodic array of copper wires. The tunability is demonstrated from 18 to 23GHz under an applied magnetic field with a figure of (Þ and permeability (mÞ constants coincident in frequency various frequencies, one would have to change the periodicity and size of the elements. Additionally, it is structures have been proposed [12–14]. We demonstrate a scheme by which continuous fre-quency tuning of the negative index is possible by using a YIG film or slab. The effect of the YIG film is to provide a ARTICLE IN PRESStunable negative m over a continuous range of frequencies on the high-frequency side of the ferrimagnetic resonance. Complementary negative is achieved using a single 0304-8853/ $- see front matter r 2007 Published by Elsevier B.V. doi:10.1016/j.jmmm.2006.12.031 Corresponding author. Center for Microwave Magnetic Materials an