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
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
Lynn Baker USSKA Consortia Washington, DC June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
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
Optics Option For DVA-1, #1 June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Optics Option For DVA-1, #2 June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Optics Option For DVA-1, #3 June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Optics Option For DVA-1, #4 June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Optics Option For DVA-1, #5 June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Lynn Baker USSKA Consortia Washington, DC June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Lynn Baker USSKA Consortia Washington, DC June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Lynn Baker USSKA Consortia Washington, DC June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Lynn Baker USSKA Consortia Washington, DC June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Lynn Baker USSKA Consortia Washington, DC June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
Physical Optics Analysis, Gaussian Feed June 3,4 2010 Lynn Baker USSKA Consortia Washington, DC
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