Satellite Antennas

Within the framework of the Danish Small Satellite Project Electromagnetic Systems has designed the antenna system for the Oersted satellite, which has been in operation since February 1999.

Electromagnetic Systems is currently designing the antenna system for the Roemer satellite, which is to be launched in 2003. These projects both involve the following phases:

  • investigation of potential antenna candidates to assess their compliance with the communication specifications, and selection of best candidate.
  • electromagnetic analysis and synthesis of the antenna element - and the feeding circuitry - to determine geometry and materials.
  • electromagnetic analysis of the interaction between the antenna element and the satellite structure to determine the position of the antenna element(s).
  • experimental verification of the analysis through measurements on antenna elements and satellite models with integrated antennas.

These phases are iterated several times with prototypes and engineering models before the manufacturing and final testing of the flight models.

One major challenge in the design of small satellite antennas is the significant degree of interaction between the antenna element and the satellite structure. For small satellites the antennas must be small and this implies low directivity. Consequently, the satellite is significantly illuminated by the antenna element radiation, and in turn it gives rise to a significant scattered field which influences the overall radiation pattern. Both asymptotic techniques, such as Physical Theory of Diffraction, and numerical techniques, such as Integral Equation/Method of Moments, have been developed to analyse this scattering, see f.x. Computational Electromagnetics . In both projects, the interaction has been controlled and exploited to help shape the radiation pattern.

Some results are published in the following papers

  • S. Pivnenko, S. Arslanagic, N. V. Larsen, D. Zibar, E. Jørgensen, O. Breinbjerg, "Pattern diversity antenna system for small satellites", Proceedings of 25th ESA Antenna Workshop on Satellite Antenna Technology, ESTEC, Noordwijk, The Netherlands, 2002, pp. 231-237.

  • E. Jørgensen, B.K. Nielsen, O. Breinbjerg and M. Lumholt, "Spherical coverage S-band satellite antenna system with cavity-backed crossed-slot radiating elements ", Proceedings of Antenn 00 Nordic Antenna Symposium, Lund, Sweden, September 2000, pp. 203-208.

  • E. Jørgensen, B.K. Nielsen, O. Breinbjerg, M. Lumholt, "A cavity-baced crossed-slot antenna element for an S-band circular polarization spherical coverage satellite antenna system ", Proceedings of the 2000 International Symposium on Antennas and Propagation, Fukuoka, Japan, August 21-25, 2000, pp. 361-364.

sattelite antennas fig. 1
Measurement of Oersted satellite engineering
model in the DTU-ESA Spherical Near-Field
AntennaTest Facility

 sattelite antennas fig. 4a
Prototype radiating element of the Roemer
crossed-slot cavity-backed antenna

 sattelite antennas fig. 4b
Two prototype feeding networks for the
Roemer antenna

 sattelite antennas fig. 5
Prototype model of Roemer satellite with
integrated antenna prior to measurements in
the DTU-ESA Spherical Near-Field Antenna Test
Facility

 sattelite antennas fig. 2
Two prototype feeding networks for the Roemer
antenna

 sattelite antennas fig. 3
Flight model integration of Oersted satellite
turnstile antenna

 

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http://www.ems.elektro.dtu.dk/research/research_projects/projects/satellite_antennas
22 SEPTEMBER 2020