SubTHz Fully-Metallic Geodesic Luneburg Lens Antenna

We propose and validate experimentally a fully metallic geodesic Luneburg lens antenna operating in the subTHz band. The antenna produces three beams pointing at 0<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula>, 40<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula>, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula>40<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula>. To facilitate the integration, the geodesic lens is folded to reduce its height to approximately 38.7% of the original Rinehart–Luneburg lens. To reduce potential leakage resulting from manufacturing and assembly tolerances at subTHz frequencies, the waveguide feeding structure has a deliberate small air gap alongside electromagnetic bandgap structures. This enhancement aims to bolster the robustness of the antenna, ensuring stable performance even in the presence of misalignments. The results demonstrate the robustness of geodesic lenses in the subTHz regime; showing their suitability for applications that require multibeam antennas at these high frequencies. The successful performance of geodesic lenses in the subTHz regime confirms its potential for operation at higher frequencies above 300 GHz.