This communication presents a Luneburg-like geodesic lens antenna with a defined footprint operating from 60 to 70 GHz. Traditionally, geodesic lens antennas are rotationally symmetric and consequently possess a large footprint. By defining the outline of the lens footprint, the overall size of the lens can be reduced while introducing new degrees of freedom to optimize its performance. An in-house ray-tracing algorithm was used to aid the design process of the lens. In the case presented, the geometric parameters were selected for the overall port performance. A final prototype was manufactured using laser powder-bed fusion (LPBF), with measurements agreeing closely with the simulated results. The proposed antenna finds applications in future wireless communication networks.

The application of lenses combined with array antennas (also known as dome arrays or dome antennas) to the next generation of terrestrial and satellite communication systems brings a wide range of advantages in terms of improved radiation performance, reconfigurability in the use case, and reduction in power consumption. To facilitate the industrial implementation of dome antennas, highly efficient simulation tools are required. In this paper, we present a streamlined implementation of ray tracing for fast and efficient numerical analysis of the far-field radiation performance of 2D multilayer dielectric lenses combined with phased arrays. Unlike commercial physical-optical methods, our proposed ray-tracing method is capable of computing the effects of internal reflections in the dome in a multilayer configuration. In addition, the method estimates the absorption losses as a result of the Joule effect. To demonstrate the effectiveness of the proposed approach, we provide comparisons of the simulated radiation patterns using our proposed ray tracing with the results obtained from commercial full-wave simulation tools.

In this study, we analyze the radiation properties of the 1λ-mode loop antenna and identify the superposition of the tangential magnetic field radiated from the two in-phase electric currents as the dominant source of specific absorption rate (SAR). Increasing the physical distance between the currents does not reduce the peak 10 g -SAR levels as the superposition of the magnetic field always generates a single 10 g -SAR hotspot in the middle of the loop. One potential solution to reduce the 10g-SAR for SAR compliance is the excitation of the two current sources with a 180-degree phase difference, this is achieved by introducing a twist in the loop. The twisted loop has two 10 g SAR hotspots with a lower peak level and also achieves a 50% size reduction.

In this paper a simple and efficient ray-tracing model is presented to evaluate two-dimensional (2D) multilayer dielectric lenses combined with arrays. The proposed algorithm is capable of accurately evaluating the reflection and absorption losses of the lens. Two examples have been simulated with the proposed algorithm and compared with a commercial full-wave simulator. We demonstrate that the proposed method provides a very good agreement with the simulations, reducing considerably the computation time, and thus offering an effective tool for design optimization.

This article applies an in-house generalized ray-tracing (RT) model to efficiently compute both the radiation pattern and the efficiency of geodesic lenses with nonrotationally 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 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 (PPW), 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 RT model. A non-rotationally symmetric water drop lens has been manufactured in a monolithic piece using the laser powder-bed fusion (LPBF) technique with successful experimental results.

This paper evaluates the suitability of additive manufacturing, with AlSi10Mg using the Laser Powder-Bed Fusion (LPBF) technique, for geodesic lens antennas. This evaluation is carried out with three different geodesic lens antennas operating in Ka- V- and G-band. In the Ka-band, an elliptically-compressed geodesic lens antenna was designed, manufactured and tested; in the V-band, the experimental results of a geodesic lens array antenna composed of four elements are shown. These two designs were manufactured monolithically to avoid leakage and misalignment between the plates. Finally, the challenges of additive manufacturing at G-band are discussed. A dual-polarized geodesic Luneburg lens antenna working at 122.5 GHz has been produced in three parts, so polishing can be carried out to reduce the surface roughness. The overall results corroborate that additive manufacturing with the LPBF technique is a promising method to produce metal-only solutions for geodesic lens antennas in the millimetre-wave regime.

This paper discusses non-rotationally symmetric geodesic lens antennas. By defining the shape of the lens footprint, additional degrees of freedom are introduced into the design process, allowing for further tailoring of the electromagnetic performance of the lens while simultaneously reducing the volume occupied by the lens. An in-house ray-tracing model for geodesic lenses has been modified to analyze this class of lenses. Examples showing the effect of modifying the lens profile are presented, with a more detailed discussion on profile presenting improved side-lobe levels at the extreme ports. The examples presented operate at 30 GHz.

This paper focuses on the analysis of the dispersion diagram of a two-dimensional hexagonal periodic structure. The periodic inclusions are placed in a parallel plate waveguide environment and are circular holes located at the vertices of the hexagonal unit cells. The connection between the geometry of the periodic structure and the dispersion diagram is discussed. The wavevector information in the Brillouin zone is illustrated using the reciprocal lattice, from which the shape of the irreducible zone can be derived. The results give insight into the characteristics of the wave propagation characteristic of hexagonal units.

This presentation discusses a ray tracing model developed to determine the radiation pattern of geodesic lens antennas with non-rotationally symmetric footprints, where the geometry of the lens is defined using spline functions. The shape of this footprint and lens height profile can be modified by changing parameters in the defined functions. The code features a significant modification to work previously published by the authors to account for the non-rotationally symmetric design. The model runs significantly faster than commercially available software.

This paper presents a half-lens antenna integrated with a reflectarray. The combination of the half-lens and the reflectarray provides additional design freedom. In this work, this design freedom is used to reduce the refractive index range required to produce a planar wavefront using a half-lens, as compared to the half-Luneburg lens. Specifically, we demonstrate that the properties of a half-Luneburg lens can be mimicked with a lens that has reduced the maximum refractive index by 30% by integrating the reflectarray with the lens.