Recent Developments in Antennas and Propagation for Space Missions Bertram Arbesser-Rastburg ESA-ESTEC, Electromagnetics & Space Environment Division PB 299, NL-2200 AG Noordwijk, The Netherlands bertram.arbesser-rastburg@esa.int Abstract— The European Space Agency has a wide range of applications for space antennas and for propagation models – spanning telecommunication, space science, satellite navigation, earth observation, launchers and manned space missions. In addition to the development of new antennas and new propagation models, ESA is also active in the area of antenna measurement techniques and in conducting propagation experiments. The presentation will provide an overview of the most recent successful activities and will address the areas of priority for the coming years. I. INTRODUCTION The European Space Agency is using the concept of “matrix management” where specialists of one domain are working together in one organisational unit and provide support to a variety of projects. In the engineering/scientific domain, specialists working in the Directorate for Technical and Quality Management [1] are combining Research and Development, addressing the evolution in the field with project support, addressing optimising, testing and troubleshooting of existing technology. Antennas and Propagation are part of the Electromagnetics and Space Environment domain, which also covers Electromagnetic Compatibility and Space Weather. The R&D programme of ESA is divided into a range of programme elements, which are associated with different levels of technology readiness levels (TRL) [2]. These elements include the General Studies Programme, which addresses the study of new, untested ideas (TRL 0 to 1), followed by the “Technology Research Programme” (TRP) which is to establish the feasibility of new technology concepts or algorithms (TRL 1 to 3). The development of new technologies to engineering model (TRL 5) and then further to flight readiness (TRL 6) as well as testing of the respective technology is typically funded by the respective directorate which is the prime user. II. ANTENNAS Several antenna developments are on-going to respond to the new challenges requested by space missions. This includes: - Ku-band single and multi-beam reconfigurable antennas for telecommunication . - Aperiodic arrays for optimized gain and power efficiency as well as minimized inter-beam interference [3] - Multi-frequency millimetre wave sparse array antennas for a geostationary atmospheric sounder (“GeoSounder”) [4]. - Multi-beam antennas based on active lenses which allow high steering angles while keeping sidelobe levels low. - Electromagnetic Bandgap (EPG) enhanced reflector feeds for multiple overlapped beams generation from a single aperture in satellite communications. - Photonic / Electromagnetic Bandgap terminal antennas for selected application where cost and thickness aspects are important. An example is shown is Fig. 1 Fig. 1 Two examples for Electromagnetic Bandgap (EBG) Antennas. Left: Navigation Antenna; Right: Leaky Wave Vehicular Planar Antenna In the area of antenna software , the European Antenna Modelling Library (EAML) has been further expanded with Electromagnetic Data format eXchange (EDX) to facilitate the transfer of data across existing and future antenna RF modelling software packages. One of the highlights in the area of antenna measurements was the verification of the RF pointing performance of the Planck telescope, which is designed to map the cosmic background radiation with a high sensitivity and angular resolution. The measurement performed at 320 GHz using an RCS acquisition allowed pointing determination and matched the calculated predictions very well, as shown in Fig. 2.