Georgina Harris 1 2-PAD 4 th SKADS Workshop, Lisbon, 2-3 October 2008 2-P 2-P olarisations olarisations A A ll ll D D igital igital Dr Georgina Harris / Prof Tony Brown SKADS System Design and Team Leader, University of Manchester Thanks to the 2-PAD Team: Manchester Chris Shenton, Tim Ikin, Aziz AhmedSaid, Richard Whitaker, Tony Brown, Dan Kettle, Mina Panahi Oxford Mike Jones, Kris Zarb Adami, Sasha Shidewy Cambridge Andrew Faulkner Astron Jan Geralt bij de Vaate, Raymond van den Brink 2-P 2-Polarisations A All D Digital 2-PAD 2-PAD
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Georgina Harris 12-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-P2-Polarisations olarisations AAll ll DDigitaligitalDr Georgina Harris / Prof Tony Brown
SKADS System Design and Team Leader, University of Manchester
Thanks to the 2-PAD Team:Manchester Chris Shenton, Tim Ikin, Aziz AhmedSaid, Richard Whitaker,
Tony Brown, Dan Kettle, Mina Panahi
Oxford Mike Jones, Kris Zarb Adami, Sasha Shidewy
Cambridge Andrew Faulkner
Astron Jan Geralt bij de Vaate, Raymond van den Brink
2-P2-Polarisations AAll DDigital2-PAD2-PAD
Georgina Harris 22-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD Aims2-PAD Aims
• To produce a flexible platform upon which to test a variety of subsystems for the Aperture Array for the SKA
• Digital beamforming – Prove it can be done
– Realistic technology projections for cost/ power
– Low self induced RFI
– Low cost interconnects are feasible
• Dual polarisation measurements
• Proof of calibration at tile level
Georgina Harris 32-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Georgina Harris 42-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
• 2-PAD will use 3 sets of array antennas
• Each antenna tile will be 16 x 16 dual polarisation elements
• The central 8 x 8 elements will be ‘active’, i.e. the signals from these antennas will be amplified and processed
• The remaining antennas will be ‘loaded’ elements, i.e. they are present only to reduce the edge effects on the central 8 x 8
• Each antenna type is due to be produced as a passive tile for RF testing
• After testing, the active antennas will be used for 2-PAD.
Georgina Harris 52-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
FlowPAD antenna
• from our colleagues at Astron
• used as a reference design by which to benchmark our other antennas
Georgina Harris 62-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
BECA
• (Bunny Ear Combline Antenna)
• Designed by the University of Manchester
• A development of a Vivaldi Structure
Georgina Harris 72-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
ORA
(Octagon Ring Antenna)
• Designed by the University of Manchester
• New Antenna Design – see talk by David Zhang
Georgina Harris 82-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD LNA2-PAD LNA
• The LNA for each antenna must be impedance matched and designed to integrate mechanically with the antenna
• There are currently three teams working on LNAs in SKADS for 2-PAD– A completely new single-ended LNA developed in Indium
Phosphide in Manchester– A differential LNA designed at ASTRON at 150 impedance for
use with FlowPAD and BECA antennas– A differential LNA made up from discrete components in
Manchester at 150 for use with FlowPAD and BECA antennas
• It is likely that the discrete component LNA will be installed on 2-PAD initially, however, it will be possible for each LNA to undergo validation on the 2-PAD platform.
Georgina Harris 92-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Gain = 72dB
Designed constructed and characterised byRichard Morrow
Gain Gain Chain Chain
Version Version 11
Georgina Harris 102-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Georgina Harris 222-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Processing Bunker DesignProcessing Bunker Design
The processing bunker will be manufactured to the basic pattern of a standard transport container.
Dual Function:
1. Provide RFI Shielding
2. Permits the processing bunker to be filled with computers before it is shipped
Georgina Harris 232-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Bunker RFI shieldingBunker RFI shielding
• Connect via screened sockets• Cables through tube• Wrap foil along cable• >60dB suppression at 1GHz, so far
ARJ45 screenedconnectors
Georgina Harris 242-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Potential SKA Station LayoutPotential SKA Station Layout
Georgina Harris 252-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
SoftwareSoftware
• A highly optimised kernel and software library has been created for the Cyclops processor from scratch in Manchester
• A comprehensive MATLAB broadband beamforming model has been developed
• We have a vendor developed software simulator for the Cyclops processor and the first version single polarisation beamformer has been implemented (in the simulator environment). This is currently being validated against the MATLAB model (refer to presentation by Aziz AhmedSaid).
Georgina Harris 262-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD should be integrated and 2-PAD should be integrated and ready for test by Q1 2009!ready for test by Q1 2009!
