Abstract: Negative permeability metamaterials and devices based on negative permeability metamaterials are described. The invention presents a new paradigm for realizing electromagnetic devices utilizing naturally available magnetic materials operating in their negative permeability spectrum. The superior advantages of negative permeability materials are utilized for providing unique electromagnetic devices including, for example, small antennas, array sensors and imaging devices. Since the property of the magnetic materials can be tuned by applying a DC magnetic field, the materials and devices of the present invention can be tunable.