Ultra-Wideband Flat Metamaterial GRIN Lenses Assisted With Additive Manufacturing Technique

This article presents the designs of ultrawideband microwave flat gradient index (GRIN) lenses, which realizes over a 108% fractional bandwidth (12-40 GHz). The frequency-independent ray optics method is employed to determine radially varying permittivity profile lenses. challenge realizing such and limitations in dielectric material choices are overcome by two additive-manufacturing-aided approaches: 1) partially infilled dielectrics with varied periodicity, ensures lens performance at higher end frequency range 2) artificially engineered (AED) subwavelength-scale metallic inclusions, enables-high leads benefits thickness mass reduction for GRIN Measured results demonstrate that lenses improve gain open-ended waveguide sources 8.7-15.6 dB wide from 12 40 GHz, realized up 23.6 dBi. Both simulation measurements presented design confirm potential implementing proposed high directivity beamforming antenna applications, across an range.