Frequency-Scanned Leaky-Wave Antenna from Negative Refractive Index Transmission Lines

A microstrip frequency-scanned leaky-wave metamaterial-based antenna is presented in this paper. It is built from two negative refraction index transmission lines fed with opposite phase using an integrated balun. The microstrip leaky-wave antenna is a two-layer structure without any vias. The antenna works well at C band from approximately 3.5 GHz to 5.5 GHz, in which the main beam scans from -40deg (backfire) to 40deg (endfire). As it does not include any interdigital capacitors or vias, it can be easily extended to millimeter-wave frequency bands.