Speaker
Description
Additive manufacturing (AM) methods are nowadays considered as a promising alternative for the fabrication of complex RF components for space applications. Among all the AM technologies, selective laser sintering (SLS) is currently the most explored technique for space applications. This is mainly motivated by the characteristics of materials used (such as metals and ceramics), for which most of the mechanical and thermal requirements for space applications are known to be met.
After several years of development in the field, SWISSto12 proposes an alternative by first creating component skeletons with AM of polymers (stereolitography - SLA) and subsequently metal coating these skeletons to enable the suitable RF functionality. The main advantages of this approach over SLS are its higher mechanical precision, increased design flexibility, and lower surface roughness. Moreover, for current SLA techniques, a large variety of polymers are commercialy available, some of which have good thermal propreties which can mitigate space compatibility issues.
Today most remote sensing and radar applications systems employed in satellite and ground-based science missions or civil applications are formed by a primary feed (typically a horn or a planar antenna) illuminating a larger secondary antenna (typically a reflector or a lens). The signals generated by the feed are then properly transformed by the secondary antenna through reflection or transmission in order to achieve the desired radiation properties of the resulting electromagnetic waves.
Though lenses and reflectors are frequently the most visible part of the antenna system, the performance of the system depends critically on the feeder. Ideally, these feeders must be intimately associated to other components, thus creating a specific subsystem called the antenna feed chain.
A key component in this chain is the orthomode transducer (OMT) that separates or combines orthogonally polarized signals. For instance, in radar applications, the use of orthogonal polarized beams helps building contrast in images. In all cases OMTs reduce the number of required feeds, which leads to savings in terms of cost and weight.
In this activity, SWISSto12 has developed and manufactured several feed-chain components for Ka-band and V-band science missions. The advantages and the limitations of stereolithography for such components have been extensively investigated and the design flexibility of AM has been exploited to propose innovative RF designs. Specifically, the following examples will be presented: a Ka-band feed chain composed of a turnstile junction OMT and a corrugated feed horn and a hexagonal array of smooth-walled, profiled horns operating in V-band.
| ESA Technical Officer | Maarten van der Vorst |
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