ORA for SKA

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ORA for SKA

• Prof. A. K. Brown
• Dr. David Zhang
• School of Electrical and Electronic Engineering
• The University of Manchester
• Email anthony.brown, david.zhang_at_manchester.ac.
  uk

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Outline

• A brief review of ORA aperture array antenna
  design at the end of SKADS
• AA-mid Antenna design for PrepSKA
• Discussions and near future plans

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Aperture Array Antennas
FLOTT (a)(d) BECA (b)(e) ORA (c)(f)
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(No Transcript)
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Three candidate designs for SKADS (1616 finite
arrays)
BECA
ORA
FLOTT
(Photo Courtesy SELEX Galileo)
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Active reflection coefficient
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Cross polarisation in the intercardinal plane at
1 GHz, based on the finite array measurement
D-plane 45o Cut
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Scanned element pattern for the centre element of
the finite array
E-plane, 0o Cut
H-plane 90o Cut
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• Change of Frequency Range
• LNA integration and feeding methods for ORA
• The ORA finite array analysis
• Measurement-noise temperature of integrated
  structure
• Manufacturability

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The infinite ORA array with 125mm element
separation
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The infinite ORA array with 112 mm element
separation
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108mm separation
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The feeding methods for ORA
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The optimisations of the feeding lines for a
lower loss
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3
1
LNA close to the radiators
For LNA wiring
Coaxial cable for single-ended feeding
LNA above the groundplane
LNAs below the groundplane, but using coaxial
cables for single-ended feedings
Shorter coaxial cables for single-ended feedings
LNAs above the groundplane
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Single-ended and differential feeding methods
The single-ended stripline
Differential coaxial cable feeding
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ORA performance with 50ohms stripline feed, 112mm
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ORA performance with differential coaxial cable
feeds, 112mm element spacing
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Single-ended Stripline feed for the 55 subarray
of the 1010 finite array tile
The active reflection coefficient
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Differential feeding method, passive reflection
coefficient measured
Element 13
Element 1
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Integration with EMBRACE front-end electronics
for further investigation
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ORA tile for EMBRACE electronics integration

• The element separation of 125 mm
• 70 ohms single-ended port for each element
• The coverage area of the tile 1.125 m2

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• Efficiency measurements
• Complete LNA integration and measure combined
  noise temperature
• Manufacturability design
• EMBRACE compatible tile
• Final choice of LNA type and optimise ORA for mid
  frequency array
• Build and test
• Pre-production manufacturing techniques

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Noise measurement of the active ORA finite array
Sub-array becomes active with power splitters
A hot/cold measurement facility is under
construction in JBO, the measured results out of
this for the finite ORA arrays will be confirmed
at THACO in ASTRON
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Further investigation of ORA tile with the
EMBRACE electronics ?
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The manufacturing cost investigation
Chemical etching A traditional
photo-lithographic technique on PTFE/woven glass
laminate
Ink-jet printing A catalyst is ink-jet
printed onto the plastic film, and then copper is
electro-formed onto the catalyst, a further
electroplating process is required
Screen printing and other technics?
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• Efficiency measurements
• Complete LNA integration and measure combined
  noise temperature
• Manufacturability design
• EMBRACE compatible tile
• Final choice of LNA type and optimise ORA for mid
  frequency array
• Build and test
• Pre-production manufacturing techniques