An Off-Broadside Zero Beam-Squinting Leaky-Wave Antenna Based on NRI-TL Metamaterials

A planar, off-broadside zero beam-squinting leaky-wave antenna operating at 5.5 GHz is presented. It consists of two oppositely-directed branches of negative-refractive-index transmission-line (NRI-TL) leaky wave antennas (LWAs), one operating in the left-handed region and another operating in the right-handed region. The two NRI-TL LWAs are fed through a 50 Ohm transmission line. The two antenna branches each radiate their main beam in opposite directions, and the combination of the two beams results in an off-broadside beam. The antenna maintains its fixed-beam operation for a wide bandwidth of 0.75 GHz, with a gain in excess of 5 dBi and radiation efficiencies greater than 70%.