Within the frame of a ESA - Networking/Partnering Initiative (NPI) PhD project, the proposed work aims to explore additive manufacturing techniques for fabricating challenging antennas at K and Ka-Band. Stereolithography (SLA) and selective laser melting (SLM) are both investigated, as well as the effect of surface treatments for SLM pieces. The proposed structure is based on a dual-moded waveguide propagating two leaky-waves radiating through crossed-slots cut on the top face. Single and dual-linearly polarized antennas with low sidelobes are conceived at 30 GHz and 23.28 GHz, then manufactured with the high precision and low roughness provided by SLA. Their complexity relies on the fact that both the geometry of the slots and the height of the ridges inside the waveguide are modulated. Especially, the dual-polarized antenna is exhibiting tapered ridges on three internal faces and an orthomode transducer, which make it almost impossible to be done without multiple assembly steps and subtractive fabrication processes. An array of eight leaky-wave antennas operating at 20 GHz has also been produced monolithically with its folded BFN using SLM. Finally, the potential of the proposed structure is pushed further to generate circular polarization, leading to SLM prototypes working at 20 GHz. Measurements show that additive manufacturing techniques allow for high performance antennas operating at microwave frequencies.
The study focuses both in Telecommunications and Earth Observation applications.
|ESA Technical Officer||Petronilo Martín-Iglesias|