Fast Leaky-Wave Antenna With Enhanced Frequency Scanning Rate by Dispersive Metamaterial Waveguide

A fast leaky-wave antenna (FLWA) with improved beam-scanning (BS) capability is proposed. The FLWA is made by a modified rectangular waveguide utilizing an array of metallic rods to enhance the spectral dispersion. In analysis, enhanced spectral dispersion is realized by mixing the Drude and Lorentz dispersions, which are determined by the waveguide and the rods. In simulation, the FLWA's BR rate is tailored by changing the metal rods, and enhanced spectral dispersion is realized below the cutoff of the original hollow waveguide. To realize impedance matching with the WR-90 waveguide, a gradient structure is designed. In experiments, a prototype is fabricated and measured. It is shown that the FLWA has a beam-scanning range from 12° to 72°, in the band from 7.15 GHz to 7.85 GHz. With these profiles, the BR rate is 6.42°/%, and an average gain is about 12.5 dBi in the whole operation band. The FLWA can be a good candidate for facilitating low-cost radars, including fast tracking, imaging, and communications.