Metal 3D printing for RF/microwave high-frequency parts

Space Systems have been historically characterised by high performance, high reliability and high cost. Every new generation of space systems tends to improve performance, keep as much as possible reliability, speeding the lead time and lower the cost. Aggressive approach is nowadays followed by some of the players of the new space ecosystem where, for instance, reliability can be relaxed thanks for the in-orbit redundancy or robustness to failures by having a constellation with a high number of satellites. This push towards the technology and system limit requires to investigate new methods for the manufacturing of RF/Microwave parts. RF devices such as those based on waveguide structures, benefit from an additive manufacturing approach in terms of radio frequency (RF) performance and compactness. However each manufacturing approach comes with specific features and limitations which need to be well understood and, in some cases, even taking advantage of them. This paper provides a short review of some of the RF/Microwave parts already manufactured using this technology. The paper will focus mainly on metal 3D printing parts since this technology is, at the moment, well accepted by the space community.