The objective of the activity is to develop frequency/polarization selective surfaces for both partially reflective surface as well as multi-frequency (sub)reflector-based configurations taking the full benefit of enabling capacity offered by the additive manufacturing techniques.

Science TTC systems, Earth observation instruments and Telecommunication system payloads are more and more calling for multi-frequency reflector-based high gain antennas. As examples, one may refer to altimeters, radiometers and SAR (e.g. COREH2O) for Earth Observation and high-gain data transmission antennas as for the JUICE mission requiring both X- and Ka-band frequencies. Multi-frequency and multi-polarisation operation is often required hence the need for Frequency/polarization Selective Surfaces(FSS) integrated with (sub)reflectors or partially reflective surface. For any spaceborne instrument mass is a critical parameter that needs to be optimized. This becomes even more important for micro satellites. With the availability of additive manufacturing techniques, it should now become possible to design low-mass and low-loss FSS sub-reflectors or small reflectors, which are built as a single piece hardware possibly including the brackets. For an optimized design, the capability of combining dielectric and conductive materials as well as electrical and mechanical graded index materials shall be assessed. The novel manufacturing techniques are expected to allow for different configurations such as printed circuit and waveguide based FSS, planar and curved objects with complex shapes, shorter lead times and last-minute design changes. Challenges that need to be looked at are thermo-elastic stability of the assembly and RF losses. The activity will consist of the following steps: - Review Earth Observation, Science and Telecom instruments or antennas that require the use of relatively small dichroic (sub)reflectors or self-standing FSSs and identify the applications and configurations that could benefit the most from the use of additive manufacturing. - Perform FSS design and sample test campaign to optimise the preferred additive manufacturing technique for 2D and 3D objects. - Design, build and test a number of single piece breadboards using additive manufacturing - Prepare development plan and roadmap