june 3,4 2010lynn baker usska consortia washington, dc1 tdp / awg update lynn baker usska consortia...
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June 3,4 2010 Lynn Baker USSKA Consortia Washington, DCLynn Baker USSKA Consortia Washington, DC 1
TDP / AWG Update
Lynn Baker
USSKA Consortia MeetingWashington DCJune 3,4, 2010
June 3,4 2010 Lynn Baker USSKA Consortia Washington, DCLynn Baker USSKA Consortia Washington, DC 2
Feed / Optics Analysis
• Wideband feeds analyzed in a range of conic and shaped optics– ATA log periodic feed, Lindgren feed (Cal Tech), QSC feed (Cornell),”11” feed (Chalmers)
– Each feed modeled in multiple optics to select best matched optics
– Efficiency and noise temperature calculated over the feed frequency range
• Results presented in papers and submitted for publication– Three talks at the URSI meeting in Boulder
– Two papers submitted to the IEEE / APS journal
– Multiple talks at two meetings in Manchester, England
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Feed / Optics Analysis
• Conclusion: Wideband feed performance dominates overall antenna performance
• Conclusion: More than one wideband feed will be required
• Improved wideband feed models under development and test
• Need to include corrugated horns in the optics trade-off analysis
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Initial Planning For DVA-1 Project
• DVA-1 prototype Antenna will be a 15 meter shaped offset, Gregorian design– Choice of diameter driven by system cost considerations
– Choice of shaped offset from previous studies of performance and cost.
– Initial optical, mechanical design work underway
• Project is planned as a partnership between TDP, DRAO, NRAO, SPDO– TDP is contributing optical and mechanical design, wideband feeds
– DRAO is contributing composite reflector design and fabrication, possibly a PAF
– NRAO is contributing the site at the EVLA, narrowband feeds, back end electronics
– SPDO is contributing system level analysis, testing plan development
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Preliminary Optics Choice For DVA-1
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Feed Indexer Concept
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Cobham/Patriot Proposal
• Cobham/Patriot is proposing to build a 15 meter offset antenna– Cobham/Patriot has seed money to pursue the design and construction of prototype(s).
– The design would include TDP shaped optics and TDP advanced mount concepts
– The antenna would meet SKA prototype specifications
– Reflectors would be panelized using Patriot stretch forming technology
– The drive systems would be standard Patriot components
– If another customer can be identified, the cost to the TDP is approximately $750,000
• A second mount would be provided to support a composite, single shell reflector– The mounts would have a common interface to support different reflectors
• Proposal would expedite the construction of a first prototype– A single shell composite prototype antenna would follow this first prototype
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Typical Panel From Primary
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Broadband Feed Development
• Multiple feeds being developed, 3 funded by TDP, others in-kind
• QSC (Cortes,Cornell), Log-Periodic (ATA), Lindgren (CalTech) feeds in the TDP
• “11” (Kildal,Chalmers) feeds being developed in-kind
• Second generation models of the feeds are designed and analyzed. Several are fabricated and under test
• A corrugated horn is being designed and analyzed for modeling in optics