A Composite Right/Left-Handed Rectangular Waveguide with Tilted Corrugations for Millimeter-wave Frequency Scanning Antenna

A novel structure for a composite right/left-handed (CRLH) corrugated waveguide that operates in the millimeter-wave band is proposed. The CRLH waveguide is comprised of a rectangular waveguide which has tilted corrugations on its bottom broad wall. By operating both above and below the cutoff frequency of the dominant mode, the rectangular waveguide provides, respectively, an inherent series inductance and shunt capacitance, and an inherent shunt inductance, and the tilted corrugations provide a series inductance and capacitance, which can support CRLH propagation. A frequency scanning antenna using this CRLH waveguide was also studied numerically and experimentally. The results demonstrate that the antenna can provide backward-to-forward beam scanning, including the broadside direction. A scanning angle from -9.9 to + 2.2deg was achieved within a 1.8-GHz frequency range in the 60 GHz band.