Programme Element: ARTES 5.1
Tender nr.: AO 1-7474
Open from: 16 May 2013
Closes on: 11 Jul 2013
Objective: to develop a retro-directive Ka-band terminal antenna using a hybrid low power analogue/digital approach.
Targeted Improvements: by designing an electronic self tracking antenna with simple and low powered hybrid analogue/digital architecture, additional sensors needed for satellite tracking can be eliminated. Power consumption of this hybrid solution can be reduced by as much as a factor of eight as compared to a full digital solution. These improvements will reduce complexity and improve tracking performance.
Current self steering antennas for satellite ground terminals require complex mechanical or electronic steering arrangements. The retrodirective array offers a refreshingly new and simple approach to this problem. It can swiftly point and track to a remote signal and retransmit back in the same direction, using simple circuits. These antennas have been known from about the 1960?s, although nothing to date has made it to a real world application, due to the many drawbacks that have recently been successfully addressed and are mentioned here below.
This activity is a further development of the ESA TRP project ?Self Focusing Retro-Reflective Antennas for Mobile Terminal Applications, AO/1-6168/09/NL/JD? which has resulted in a practical 2.4 GHz 1x5 array with the following advantages: (1) Operates at RX signals of -120dBm, (2) Constructive combination of signals on RX and TX, (3) Compensates for beam pointing error due to TX/RX frequency offset, (4) Operates with QPSK/16QAM modulation via a pilot tone (5) CP array has 8.5% bandwidth and beam steering of +/- 40 degrees, (6) Power consumption < 500mW (1x5 array), (7) Simple enough to fit on a single planar structure.
There are two main tasks within this activity: (1) Modification of the existing analogue architecture to provide enhanced operation with phase modulated signals (e.g. QPSK and 16-QAM) and hence eliminating the need of a pilot tone . This is likely to include a hybrid low power analogue/digital approach. (2) Scaling in frequency of the existing 2.4 GHz antenna and circuits to frequencies as high as Ka band with MMIC technology.