C. Mangenot

Shaped single-feed-per-beam multibeam reflector antenna

Current Ka-band multibeam satellite antenna systems often use one feed per beam, but involve a high number of reflector antennas (four for transmit and four for receive) to realise both acceptable crossover levels and spillover losses (Rao, 1999). Several developments go on to reduce the number of reflectors to one for transmit and one for receive at the cost of much complexity in the feed array and beamforming. Orthogonal efforts aim at developing antennas that both receive and transmit. Here we present a new concept (patent pending) where a shaped reflector reduces both the number of feeds per beam and the number of reflectors to one (with separate receive and transmit antennas). The price paid is an oversizing of the reflector making the reflector area comparable to the total area of the conventional four-reflector solution.

Projection based methodology for designing non-periodic, planar arrays

An effective procedure for designing non-periodic, planar array antennas is discussed. It amounts to replicating by orthogonal projection two radiation mask tailored, non-periodic, linear arrays. Meeting the design specifications by these linear arrays guarantees their fulfillment in the entire field of view. The advocated methodology is illustrated by tackling a demanding design problem referring to a satellite communication application, requiring a narrow beam and low side-lobes levels.

Recent advances on array antennas for multibeam space applications

The paper provides a short overview on recent ESA developments on array antenna architectures for satellite antennas generating a multiple spot beams coverage with a single aperture. In particular, solutions based on direct radiating arrays, discrete lens arrays, and arrays magnified by confocal reflectors will be discussed. ESA is supporting since several years activities in this challenging domain.

Recent developments in feed array for Ka-band FAFR antenna

The present paper focuses on TCS21 achieved results, which have not been published so far and that are fully consistent with CDR predictions. A synthesis of study main achievements is presented.

Non-periodic direct radiating arrays for multiple beam space telecommunication missions

This work identifies the non-periodic array configurations for a space multibeam communication satellite which minimise the number of active chains while ensuring a proper control of both the sidelobe (SLL) and grating lobe (GL).

Interleaved multi-band pyramidal antennas combining radio navigation and telemetry satellite applications

We have proposed and validated through simulations the possibility to interleave two pyramidal multi-band antennas. This new design enables to overcome bandwidth limitation problems as only one trap is now needed per radiating element on the radio navigation antenna. The feeding network is simplified as the two applications are now separated and polarizations can be defined independently for the two applications without significant impact on antenna design.

Very large antenna for low frequency space-borne SAR

The recent frequency allocations for space-borne radars in P band (432-438 MHz) have aroused the interest of the scientific community. Possible applications for radars operating in this frequency band range from ice sounding to biomass monitoring. Due to the low operational frequencies and accordingly long wavelengths, the required surface for a P-band radar antenna is in the order of 60 or more square meters. Such dimensions demand lightweight and robust mechanical structures, capable of a compact stowed volume in order to be compatible with small and low cost launchers. In the frame of the ESA contracts on Very Large Space Antenna Apertures and on Passive Subarray Technological Development, Thales Alenia Space studied and proposed an innovative architecture satisfying both the high performance requirements and the mechanical constraints. Several prototypes have also been manufactured and a test campaign validated the RF design.

Antenna technologies from 435 MHz to 356 GHz for ESA's candidate Earth Explorer satellite missions

As a result of down-selection after Phase 0 for the 7th Earth Explorer mission following the User Consultation Meeting held in Lisbon, Portugal in Jan 2009, three candidate missions were selected for further feasibility investigations (Phase A) [1]. Each of the candidate missions is now being defined in detail through two parallel and competing industrial system studies and supporting complementary science and technology studies, aiming to the final down-selection in 2012, followed by the mission implementation with a planned launch in the 2017 timeframe. The microwave payloads of those candidate missions cover the frequency range from 435 MHz to 356 GHz. The BIOMASS candidate mission aims to measure the global forest biomass at P-band (435 MHz) using the synthetic aperture radar (SAR) technique. Due to the long wavelength and large distance between the satellite and the Earth, a very large antenna aperture is required (50–100 m2). The CoReH2O candidate missions aims to quantitatively measure the global distribution of snow over land and sea ice at X-(9.6 GHz) and Ku-band (17.2 GHz) using the SAR technique. The PREMIER candidate mission, carrying an infrared limb sounder and a microwave limb sounder, the latter covering the frequency range of 313–356 GHz, aims to measure atmospheric composition in the upper Troposphere and lower Stratosphere. Three very distinct antenna technologies are required for enabling those satellite missions. This paper describes the different antenna concepts proposed and corresponding technology developments which are on-going.