Additive manufacturing (AM) is emerging as a key technology for the minimization and integration of microwave antenna systems. Among the several AM processes, selective laser melting (SLM) is rather convenient for waveguide components, since it allows for all-metal parts with a mechanical accuracy within 30-60 μm and an equivalent surface electrical resistivity in the range of 10-20 μΩcm. This paper reports on the assessment of the SLM applicability to the manufacturing of dual-polarization waveguide components operating in Ka-band, namely, a septum polarizer, a smooth-wall feed horn integrated with the septum polarizer, and an orthomode transducer (OMT). In order to achieve high electromagnetic performance in the Kaband, the architectures have been optimized for the manufacturing process, above all in terms of orientation on the building platform and minimization of supporting structures. As a consequence, the corresponding prototypes exhibit measured performances in significant agreement with the predicted values. As an example, the return loss of all the components has been measured to be as high as 25 dB, while the measured isolation between the rectangular waveguide ports of the OMT is better than 47 dB.

Additive manufacturing technologies have been increasingly applied to the development of radio frequency components in the past few years. Indeed, the free-form capability of these processes allows for the design of novel components, whose actual implementation through conventional machining is rather complex or even not possible. This paper describes a monolithic WR51 component integrating three radio frequency functionalities, namely, bending, twisting, and filtering. Three aluminum prototypes with different bending/twisting radii have been manufactured through the selective laser melting process. They exhibit a measured rejection higher than 60 dB in 17.5 and 21.2 GHz, and a measured return loss better than 20 dB in 12.5 and 15 GHz. Significant mass and envelope reductions (higher than 60% depending on the bending/twisting radius) with respect to the reference subsystem with distinct waveguide components are achieved. These results assess the effectiveness of 3-D metal printing in the miniaturization and integration of waveguide systems.

3D-printing is leading to a major transformation in many industrial and application sectors, ranging from medical to aerospace. In the space sector, 3D-printing has firstly been adopted for the development of structural and thermal parts, such as brackets and heat pipes. In more recent years, thanks to improvements in precision and surface roughness, 3D-printing technologies have steadily been investigated also for the development of radio frequency components and advanced payloads. Indeed, the unique features of 3D-printing, including the free-form capability and the ease for customization, make these manufacturing technologies very appealing in the development of complex radio-frequency front-ends for space applications, including New Space constellations and next generation software-defined communication satellites. They also enable a drastic simplification of mechanical designs by reducing the number of interfaces and assembling screws of large radio-frequency front-ends, thus leading to significant mass savings and higher integration. This paper briefly reports on recent advances in 3D-printing that have been carried out according to the current trends in radio-frequency front-ends for satellite communications.

In this letter, the design and the three-dimensional (3-D) printing of high-performance feed horns operating within Ku- and V-bands are presented. A smooth-wall architecture has been preferred in order to ease the manufacturing and to enhance the 3-D printing quality. A suitable design procedure has been developed for the synthesis of dual-band smooth-wall feeds. Single-band and dual-band all-metal prototypes have been manufactured through the selective laser melting technology. A remarkable agreement between the predicted and measured performances has been achieved also for the higher frequency Q/V-band feed horn with measured return-loss higher than 33 dB, cross-polarization lower than −28 dB, and peak gain of 25 dBi.

As a part of the SKA-Low design process, several prototype stations have been deployed on the Murchison Radio-astronomy Observatory in Western Australia, to test a variety of aspects of the planned system. Known as the aperture array verification system (AAVS), several versions have been deployed, starting with the 16-element AAVS0.5 (circa 2013), moving onto the 256 element AAVS1 (2016 to 2017),¹ and finally to the 256 element AAVS2 deployed in 2019.² (The initial phase of AAVS2 deployment comprised three clusters of 16 elements each, known as AAVS1.5.) All these systems shared a quasi-random distribution of antenna elements; the elements themselves are log-periodic dipoles known as the Square Kilometre Array log-periodic antenna (SKALA) and these have also evolved with the various deployments; the elements in AAVS2 are SKALA4.1 antennas.³

The spectral smoothness of the station directivity response is a key feature of the low-frequency instrument of the Square Kilometre Array (SKA1-Low).¹ This requirement arises from the study of the Cosmic Dawn and the Epoch-of-Reionization, which are some of the most significant science cases of SKA1-Low. The redshifted signal from the 21-cm Hydrogen line can be separated from the (much brighter) foreground emission leveraging on their different spectral properties, and this motivates the requirement for a spectrally smooth antenna response.²