Fig. 2From: Metamaterials and imagingExamples of negative index materials. a The first demonstration of NIM by SRR array with metallic wires in microwave. [21] b SEM image of a fishnet structure which functions as a near-infrared (NIR) frequencies operating NIM [26]. c Polarization-independent NIM based on a single-layer coaxial waveguide structure [34]Back to article page