A NRI-TL Metamaterial Leaky-Wave Antenna Radiating at Broadside With Zero Beam-Squinting

An implementation of a planar fixed-beam leaky-wave antenna that radiates at broadside is presented, consisting of a periodic arrangement of negative-refractive-index transmission-line (NRI-TL) metamaterial unit cells. Using an experimental prototype of the antenna, it is shown that each branch of the antenna radiates a beam in opposite directions, and the combination of the two beams results in a symmetric broadside beam over a wide measured zero-beam-squinting bandwidth of 1.1 GHz (23%) around the design frequency of 5 GHz. This is well within the 80% measured -10 dB reflection coefficient bandwith. Furthermore, the antenna has a size of 3.42λ
₀
× 0.125λ
₀
× 0.025λ
₀
at 5 GHz.