Evaluation of Losses in 3-D-Printed Geodesic Lenses Using a Ray-Tracing Model

Abstract

This paper applies an in-house generalized ray-tracing model to efficiently compute both the radiation pattern and the efficiency of geodesic lenses with non-rotationally symmetric shapes. Losses due to ohmic effects and surface roughness are included in the model. These losses are very relevant for monolithic geodesic lens antennas as postprocessing techniques cannot be applied to reduce the surface roughness of the internal part of the metallic plates. The model is validated by comparison with full-wave simulations for three different lenses: a circular flat parallel-plate waveguide, an elliptically-compressed geodesic lens, and a water-drop lens. These results show a reduction in computational time by a factor of 600 using the ray-tracing model. A non-rotationally symmetric water drop lens has been manufactured in a monolithic piece using the laser powder-bed fusion technique with successful experimental results.