In this letter, a parallel-plate waveguide half-Luneburg geodesic lens multiple-beam antenna optimized for additive manufacturing is designed and validated experimentally in the Ka-band. Two prototypes were manufactured in AlSi10Mg through laser powder-bed fusion and measured in an anechoic chamber. The compact and lightweight prototype optimized for additive manufacturing demonstrates excellent RF performance while significantly reducing mass and mechanical complexity. Specifically, misalignment errors present in previous studies are solved, improving side lobe level by up to 10 dB. A maximum realized gain of 22.1 dBi is measured at 28 GHz. This singlepiece, compact and lightweight design is particularly attractive for applications having mass restrictions and limited space like millimetre-wave systems on board small satellites.
Here, we propose a low profile polarizing technique integrated in a parallel plate waveguide configuration, compatible with fully metallic geodesic lens antennas. The geodesic shape of the antenna is chosen to resemble the operation of a Luneburg lens. The lens is fed with 11 waveguide ports with 10°separation producing 11 switchable beams in an angular range of ±50°. Two metallic polarizing screens are loaded into the aperture of the antenna to rotate the electric field from vertical linear polarization, which is the polarization of the TEM (transverse electromagnetic) mode supported in the lens, to +45°linear polarization. Since the polarizing unit cells are integrated into the aperture of the antenna, the final design is compact. Additionally, the size of the polarizing unit cells is about 0.55λ at the central frequency of operation making the antenna suitable to produce an array formed of stacked lenses. A prototype of the antenna in the Ka-band was manufactured and tested, verifying the performance obtained in simulations.
Quasi-optical beamformers provide attractive properties for antenna applications at millimetre-wave frequencies. Antennas implemented with these beamformers have demonstrated wide angle switching of directive beams, making them suitable as base station antennas for future communication networks. For these applications, it is essential to ensure a high beam crossover gain to provide a robust service to end users within the steering range. Here, we propose a geodesic generalized Luneburg lens antenna operating from 57 to 67 GHz that provides increased crossover gain compared to previously reported geodesic Luneburg lens antennas. The focal curve of the generalized Luneburg lens can be displaced from the beamformer, allowing for a higher angular resolution in the placement of the feed array along the focal curve. The lens is fed with 21 ridge waveguides with an angular separation of 5.1 degrees, thus providing beam steering in a 102-degree range. The peak realized gain varies from 19 to 21 dBi throughout the steering and frequency ranges and the beam crossover gain is roughly 3 dB below the peak gain. The simulations are experimentally validated.
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