Apparatus for receiving and transmitting electromagnetic signals are disclosed herein. In some embodiments, an apparatus includes a positive refractive index (PRI) medium; a negative refractive index (NRI) medium having a first side and a second side disposed in the PRI medium; a plurality of first transmission lines, each first transmission line having a first end extending toward the first side of the NRI medium; and a plurality of second transmission lines, each second transmission line having a second end extending toward the second side of the NRI medium, wherein a plurality of electromagnetic signals travelling in a first direction, enters the PRI medium and travels along the plurality of first transmissions lines and exits into first side of the NRI medium, passes through the NRI medium and exits through the second side of the NRI medium into the PRI medium along a first one of the second transmission lines.