Wide-Angle Beam-Scanning Millimeter-Wave Linear Antenna Arrays Facilitated by a Slim High Dielectric-Constant Superstrate

This article presents a new design methodology to achieve exceptionally wide-angle beam-scanning performance for linear millimeter-wave (mm-Wave) antenna arrays, e.g., the range of the 3-dB realized gain drop from the peak is larger than ±90°. The innovation lies in the integration of a slim high dielectric-constant superstrate (HDS) on top of a conventional patch antenna array. The gap is around $0.14\lambda _{0}$ . This slim HDS effectively enhances the 3-dB beam-scanning range of the original array from ±60° to ±91°. This significant improvement is achieved through the increased element beamwidth, reduced mutual coupling between elements, and the traveling-wave effect, all enabled by the HDS. Theoretical design guideline for antenna array to achieve wide-angle scanning and comprehensive operating principle analysis of the HDS is carried out. To verify the concept, two design prototypes, i.e., a ten-element and a four-element patch array with the PCB-based HDS-mimic metasurfaces (equivalent $\varepsilon _{\text {r}} =19$ ), were developed that feature low cost, high integration, and up to ±90° half-power beamwidth (HPBW) scanning coverage. The novel design method is anticipated to find extensive applications in mm-Wave phased array technologies that require extensive broad beam-scanning performance.