Highlights of 45 years of Antenna Engineering, of which 35 with ESA, are reviewed with emphasis on R&D and innovation. The paper focuses on some new concepts that were successfully demonstrated, developed in industry and used for real projects. Conclusions include some possible lessons learned and trends for the future.

The number of distinct market areas that a single Eutelsat Satellites has to address is ever increasing. This implies that a number of antennas required on a given platform is also increasing. Consequently careful design of the antenna farm is required with judicious trade-offs of antenna apertures, configurations, frequency plans and repeater performance in order to meet the mission requirements and a feasible spacecraft design within a given schedule.

On W7, there are seven antennas to generate eleven service areas on uplink and downlink in Ku-band FSS and BSS: four deployable antennas and three earth deck antennas. On W3B there will be five antennas to generate ten service areas including uplink and downlink functions in Ku-band FSS and BSS as well as Ka-band. The paradigm one coverage equals one antenna is superseded and this presents interesting challenges for the mission definition and industry.

The design and development of space antennas, both for satellite and user terminals, involves a large spectrum of electromagnetic modelling problems, including guided-wave propagation in complex structures, full-wave modelling of large arrays, accurate modelling of reflector antennas and "high-fidelity" prediction of antenna interactions. Synthesis, analysis and optimisation issues need to be addressed, making sure that a single set of configuration and performance data can be used through the entire design cycle. The European Antenna Modelling Library project has been initiated by ESA in 2004 to support development activities along these lines, covering the three key processes in space antenna design: synthesis, analysis and optimisation, for the most relevant antenna classes. The European Antenna Modelling Library is an open platform arranged around a common language for data exchange and aimed at providing a consolidated set of algorithms and tools, while fostering the development of new ones as needed by the evolution of antenna technology. So far, a first step has been made in the above direction with the combination of a number of well established modelling tools, like TICRA's GRASP, IDS's ADF-EMS and SATIMO's SatSim, into a set featuring all request modelling capabilities and equipped with efficient data exchange. The project is based on the close co-operation among tool developers and modelling experts ensuring that new modelling solutions are quickly adopted in engineering tools.

The Electromagnetic Data Exchange (EDX) language system has been developed in the EAML and ACE projects. The diversified nature of electromagnetic modelling techniques and the quest for the best modelling solutions for each problem encountered, make it necessary to use different tools in combination to take advantage of the most efficient method on each part of an antenna system at different stage of its design and development cycle. The exchange of data among the software tools is therefore a very important aspect of antenna modelling, both for research activities and for industrial use, and the primary approach used for this purpose is the exchange of data in files. This paper is intended as an introduction to EDX presenting its structure and advantages as well as a very short example of its use.

Abstract tex currently not available.

With more than 300 Flight Model units delivered so far for geostationary spacecrafts embarking classical payloads, Thales Alenia Space France is one of the major actor in the field of Telecommunication Space antennas. In addition to this heritage, three recent programs have required the development of new antenna products that are now under manufacturing phase. This paper will first of all present a description and the main performances of these recently developed antennas.

The first program is CIEL2, for which a Ku-band multi-beam antenna subsystem, with frequency reuse, based on 3 deployable reflectors and transmit only or transmit/receive compact feeds, has been proposed for a cellular coverage over North America. Each primary feed consists of 18 to 19 horns operating in circular polarization, and also includes one tracking RF chain, in order to achieve a global beam pointing accuracy of 0.05° or better, on the 54 telecom beams. The concept heritage for this program was based on Ka-band breadboard and EQM, performed for multimedia broadband payloads in the frame of ESA and CNES studies. The second one is W2A. The spacecraft embarks a HARRIS 12m diameter unfurlable mesh reflector with a high power multi-feed, to provide 6 shaped linguistic beams over Europe for a S-DMB mission. The transmit/receive primary feed consists of 21 horns operating in dual circular polarization, and a very compact high power orthogonal Beam Forming Network.

The last one is the Global*star 2 constellation with 48 Low Earth Orbit satellites. The 16 beam coverage (54.3° in total), is ensured at receive by a L-band (1610.0 - 1626.5 MHz) active antenna and at transmit by 2 conical S-band (2483.5 - 2500 MHz) antennas with 10 and 6 spots respectively. The antennas are operating in Left Hand Circular Polarization.

The Rx active antenna has been designed by Thales Alenia Space France with:

- an array of 52 radiating elements with a spacing of 0.6 l

- 52 cavity filter / micro-hybrid LNA modules

- a passive Beam Forming Network with constant amplitude and phase laws

- DC network for LNAs supply

- an active thermal control for the antenna assembly Flight models Manufacturing and test will be performed by Thales Alenia Space Italy.

The design, manufacturing and testing of the 96 FM transmit antennas is under Thales Alenia Space France responsibility. It consists of an Outer/Central antenna realized with 9 sub-arrays of 16 elements and a dedicated horn on the one hand, and a Middle antenna with 8 sub-arrays in the other hand . The passive Beam Forming Networks are manufactured in bar-line technology. Concerning the future trends for geosynchronous telecommunication spacecrafts, the main evolution are:

- an increase of the number on antennas requesting multi-frequency or multi-beam concepts with a single radiating aperture

- an increase of the input RF power, which leads to always more efficient thermal control, and a need to reconsider the multipactor design rules for multi-carriers operating conditions for full metal equipments

- pattern re-configurability and traffic flexibility to face unexpected new demands and always longer satellite lifetime.

A new call for Core Earth Explorer Mission ideas was released by the European Space Agency on March 2005. In May 2006, six candidate missions from the twenty-four submitted proposals were selected for further assessments. BIOMASS, one of the six selected mission ideas, will carry a P-band SAR for global observation of above ground biomass and associated geophysical parameters as a primary objective. Another candidate mission, CoRe-H2O, will provide dual-frequency X/Ku-band SAR observations of snow cover, glaciers and sea-ice for retrieving the depth, snow-water equivalent as well as other important characteristics. These missions will provide high-resolution radar observations at frequencies never flown before in space. A third candidate mission, PREMIER, will carry an infrared and a sub-millimetre-wave (340 - 500 GHz) limb sounders (STEAM-R) for observation of tropospheric and stratospheric exchange processes. STEAM-R is a Swedish national contribution to the Explorer programme. All of the candidate missions are being assessed through two parallel industrial studies at phase 0 level for further down selection in Jan. 2009, with a projected launch in the 2015/16 timeframe.

In terms of antenna needs, they all require challenging novel antenna technologies. The BIOMASS mission requires a very large, deployable P-band antenna (e.g. 80 - 110 m2) with full polarisation capability, good radiometric stability and sufficient cross-polarisation isolation. CoRe-H2O requires a dual frequency (9.6 and 17.2 GHz) antenna with dual-polarisation capability (VV and VH) and good radiometric stability. PREMIER requires a large, light-weight and highly stable push-broom antenna with high pointing stability and stable beam pattern. This paper describes the high level antenna technology needs and corresponding requirements, as derived from the overall system requirements. An overview of ESA's antenna technology development activities is given which are relevant to those needs.

This paper presents the development and the results of the qualification activities of the 12m unfurlable Reflector Assembly of the Large Deployable Antenna (LDA), jointly developed by the Prime Contractor: Thales Alenia Space Italia and several Partners, under an ESA contract. The qualification campaign was completed in year 2007 opening near term opportunities for space applications relying on a European technology.

The Russian subcontractor: NPO EGS and RSC ENERGIA designing, manufacturing and test qualifying the Reflector and hold-down system (LHS) of the Reflector.

The west European countries subcontractors have designed important components like a big mechanical hinge, a trimming mechanism and the antenna hold-down. The LDA system requires four hinges (ADB) (by HTS - Switzerland) to deploy the limbs and to locate the opened antenna in the selected position in order to have the proper distance from the satellite and the RF feed.

A reflector trimming mechanism (RTM) (by SENER - Spain) is installed between the tip of the deployed antenna limbs and the Reflector. This mechanism is used to trim the Reflector, recovering the thermo-elastic distortion. Two big hold-down (AHD) (by STEYR MAGNA-Austria) have been designed to hold the limbs of the Arm during launch.

The paper illustrates the LDA development phases, starting from the requirements definition, passing to the antenna configuration description and going throughout the performed design analyses which have allowed to hold the successful CDR's of all the LDA components. The paper will continue with a description of the qualification of all the LDA components.

The final section of the paper will provide an overview of the LDA possible applications at System level.

Antennas are receiving more and more attention in the field of intellectual property, and particularly in the field of patents. In the presentation, we will focus on the requirements of the European Patent Convention concerning patentability, some specific differences between European Patent Law, US Patent Law, and Japanese Patent Law. As well, some trends in the field of antennas will be discussed, including computer implemented inventions and software. Examples of the (im)possibilities of patenting antenna design software will be given.