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A negative-index slab of metamaterial can be formed by an electrical transmission line made of cells containing capacitors and inductors. When this is sandwiched between two positive-index transmission lines, the overall circuit forms a negative-index lens. (a) A map of the electric field over the circuit reveals what happens when an antenna source is placed in the medium (white spot on source plane): the near-fields build up across the slab, resulting in the "hot spot" on the far side (red). These fields then decay, producing an image that contains more near-field components than could be imaged with any positive-index lens. (b) This improvement can be seen in a "cut" of the electromagnetic field across the object (green curve) and the image (blue) planes. The red curve is the best image that could be achieved using a positive-index lens due to the diffraction limit.