Selective laser melting process of Al–based pyramidal horns for the w-band: fabrication and testing

In the context of exploring the possibility of using Al-powder Selective Laser Meltingto fabricate horn antennas for astronomical applications at millimeter wavelengths,we describe the design, the fabrication, the mechanical characterization, and theelectromagnetic performance of additive manufactured horn antennas for the W-band. Our aim, in particular, is to evaluate the performance impact of two basickinds of surface post-processing (manual grinding and sand-blasting) to deal withthe well-known issue of high surface roughness in 3D printed devices. We performedcomparative tests of co-polar and cross-polar angular response across the whole W-band, assuming a commercially available rectangular horn antenna as a reference.Based on gain and directivity measurements of the manufactured samples, we finddecibel-level detectable deviations from the behavior of the reference horn antenna,and marginal evidence of performance degradation at the top edge of the W-band.We conclude that both kinds of post-processing allow achieving good performancefor the W-band, but the higher reliability and uniformity of the sand-blasting post-process encourage exploring similar techniques for further development of aluminumdevices at these frequencies.