An innovative study published in IEEE Transactions on Terahertz Science and Technology, March 2025, introduces a new Sub-THz Fully-Metallic Geodesic Luneburg Lens Antenna, confirming its potential for operation at higher frequencies above 300 GHz.
This design offers:
- A multi-beam antenna operating in the D-band
- Gain exceeding 22 dB, side-lobes below -14 dB, and scan losses under 0.3 dB at 40º
- Lower feeding network complexity compared to array antennas
This study was conducted by an international collaboration with Pilar Castillo-Tapia, Shiyi Yang and Oscar Quevedo-Teruel from KTH Royal Institute of Technology, Stockholm (Sweden), Nelson J. G. Fonseca at Antenna and Sub-Millimetre Waves Section, ESA, Noordwijk (The Netherlands), Ángel Palomares-Caballero at IETR, Rennes (France), and Jean-Paul Guillet, project contractor at the IMS Laboratory (France).
The project is funded by ESA with OSIP Program, Contract number 4000134617.
Detail:
https://doi.org/10.1109/TTHZ.2025.3548452
P. Castillo-Tapia, S. Yang, Á. Palomares-Caballero, J.-P. Guillet, N. J. G. Fonseca, and O. Quevedo-Teruel, “Sub-THz Fully-Metallic Geodesic Luneburg Lens Antenna,” in IEEE Transactions on Terahertz Science and Technology (2025).
Abstract:
We propose and validate experimentally a fully metallic geodesic Luneburg lens antenna operating in the sub-THz band. The antenna produces three beams pointing at 0, 40 and -40 degrees. 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 sub-THz 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 sub-THz regime; showing their suitability for applications that require multi-beam antennas at these high frequencies. The successful performance of geodesic lenses in the sub-THz regime confirms its potential for operation at higher frequencies above 300 GHz.
Proposed modulated geodesic lens antenna working in the sub-THz band. The top figures display the central waveguide feed in a top view and the flare in a side view. The bottom figure offers an exploded view of a segment of the feeding structure, emphasizing the air gap by highlighting it in blue. Variables are denoted by blue letters. WWG represents the width of the waveguide, while LWG_center denotes the length of the central waveguide. Lflare and Hflare stand for the length and height of the flare. Rlens indicates the radius of the modulated Luneburg lens. Ggap specifies the height of the designed air gap.
