1. DVA-1 Baseline Optical Design
Lynn Baker
USSKA Consortia Meeting
Washington DC
June 3,4, 2010
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

2. DVA-1 Optics Parameters
Feed opening angle of 55 degrees, nominally -16 db. feed taper on secondary
Compromise value to accommodate some wideband feeds
Will accommodate a corrugated horn of appropriate design
Low edge taper reduces spillover and reduces wide angle sidelobes
Wider opening angles increases the primary size
Possible to design a different subreflector, different angle, for a given primary
Shaping controls distribution of power in the aperture
Trades aperture efficiency versus near in sidelobe levels
Different shaping has different caustic sizes, effects the accommodation of a PAF
Shaping gives high efficiency, while maintaining very low wide angle sidelobes
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

3. Lynn Baker USSKA Consortia Washington, DC
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

4. General Optical Configuration
Subreflector location is a compromise between support frame and primary size
Lower minimizes secondary / feed framing height
Higher makes the primary smaller
Larger opening angle shifts the subreflector lower, primary grows
Effectively favors higher gain feeds
Feed high is tentatively chosen for mechanical advantages
Feed low has advantages for system noise temperature
Shielding is needed to mitigate ground noise pickup
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

5. Optics Option For DVA-1, #1
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

6. Optics Option For DVA-1, #2
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

7. Optics Option For DVA-1, #3
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

8. Optics Option For DVA-1, #4
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

9. Optics Option For DVA-1, #5
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

10. Lynn Baker USSKA Consortia Washington, DC
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

11. Lynn Baker USSKA Consortia Washington, DC
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

12. Lynn Baker USSKA Consortia Washington, DC
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

13. Lynn Baker USSKA Consortia Washington, DC
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

14. Lynn Baker USSKA Consortia Washington, DC
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

15. Physical Optics Analysis, Gaussian Feed
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC

16. Lynn Baker USSKA Consortia Washington, DC
Final Choice Of Optics
Interaction with CPG is critical
Provide detailed antenna patterns for science performance evaluation
Include various feeds including corrugated horn for evaluation
Compare model results for ATA feed with ATA measured results
Feed limitations should not effect optics design
“Hardware is destiny”
Multiple feeds can exploit different features of the optics
Accomodating a PAF at “prime caustic” is under study
Preliminary analysis suggests a modestly larger PAF will work
June 3,4 2010
Lynn Baker USSKA Consortia Washington, DC