Retrodirective Antenna - Retrodirective Antenna, ARTES 5.1, 7C.014

  • Status
  • Status date
  • Activity Code
  • Address the market needs of K/Ka-band user terminal antennas by simplifying the tracking hardware for mobile applications.

  • Produce a K/Ka-band self-steered antenna demonstrator breadboard using hybrid analogue/digital retrodirective antenna techniques

  • The system consists of retrodirective IF circuits developed by QUB and a K/Ka-band frontend developed by IMST

  • The retrodirective methods used draw on the experience of QUB producing similar antennas at L band frequencies

  • The retrodirective antenna offers real-time tracking capacity with minimum DSP usage

  • The K/Ka-band frontend is based on COTS MMIC GaAs components. An additional development plan outlines how further integration can achieve a higher TRL.

  • This has produced the first practical demonstration of a 2x4 element K/Ka-band retrodirective breadboard prototype employing a hybrid analogue/digital delay locked loop (DLL) phase conjugator.

  • Produce a K/Ka-band retrodirective antenna breadboard with sufficient simplicity, low cost and power consumption to have the potential to be scaled up for applications such as ground user terminals

  • The ability to operate at K/Ka-band with closely spaced satellites using the same frequency spectrum, and solving some of the related control aspects.

  • Providing potential for K/Ka-band and retrodirective circuits to be simple enough to be combined onto a custom chip that can be integrated with a K/Ka-band antenna array

  • Real time tracking

  • Tracking circuits operating in the analogue domain with minimal DSP processing overhead needed.

  • No requirement for fast A/D and D/A conversion within the tracking circuits since tracking is carried out in the analogue domain

  • Automatically transmits signal back in the direction from which it receives without prior knowledge of the satellite position

  • Reduction in the requirement for array calibration since the retrodirective array is self-calibrating

  • Does not require additional position information of satellite during tracking phase, eg from GPS, accelerometers etc., hence no sensor hardware required

  • Instant signal acquisition (if the satellite to be acquired is transmitting on a unique frequency)

  • Retrodirective IF circuits operate at relatively low frequencies and consequently can use low frequency, low powered components

  • The digital control aspects for the overall array operate in frequencies in the kHz frequency range, therefore can use low powered microcontrollers

  • The K/Ka-band frontend makes use of IMST’s previous experience in producing high performance frontends

System Architecture
  • The retrodirective circuit utilises a hybrid analogue/digital phase conjugating architecture drawing on the experience of producing such systems at L-band

  • In order to deal with some of the more challenging aspects of operating at K/Ka-band, such as the ability to select a particular satellite in a range of closely spaced satellites using the same frequency spectrum, the retrodirective circuits will make use of low powered microcontrollers to provide some “intelligence” to the beam steering

  • The K/Ka-band frontend consists of up/down conversion chain to an IF frequency compatible with the retrodirective circuits.

  • Define specification for K/Ka-band retrodirective antenna

  • Define specific critical breadboards to be designed – Milestone 1: Consolidated requirements & critical breadboards definition

  • Critical breadboard design

  • Critical breadboard Manufacture 

  • Critical breadboard test – Milestone 2: Breadboard Test Report

  • Baseline design for final breadboard – Milestone 3: Baseline Design Review

  • Detailed design for final breadboard – Milestone 4: Detailed Design Review

  • Final breadboard test of – Milestone 5: Test Readiness Review, Milestone 6: Test Review Board

  • Final review – Milestone 7: Final Review

Current status

Project now completed from Feasibility Study to Final Demonstration.

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