E-Plane-Focused Partial Maxwell Fish-Eye Lens Antenna for Multibeam Wide-Angle Scanning

This letter presents a multibeam wide-angle scanning antenna based on the E-plane-focused partial Maxwell fish-eye (PMFE) lens operating in Ka-band. The gradient equivalent refractive index distribution of the lens is realized by the parallel-plate waveguide partially filled with dielectric material, which can support the E-plane focus. The lens is fed by a series of rectangular waveguides arranged along the straight cut line to realize the multiple beams. To improve the impedance matching, the dielectric wedges are loaded in the interface between the feeders and the lens. The E-plane broadening of waveguide feeding ports effectively alleviates the gain drop of wide-angle scanning. The measured results of the prototype show a beam scanning range more than ±90° with the aperture efficiencies between 57% and 85.7%. The good impedance matching is also obtained in the operating band. The proposed PMFE lens antenna has the application potential in the low-cost millimeter wave multibeam systems.