1. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics By Germán Cortés M. Cornell University Ithaca NY 14853, USA National Astronomy and Ionosphere Center SKA-TDP AWG Antenna Workshop San Francisco, March 13-14, 2008

2. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Overview Introduction SKA TDP Dishes + WBSPF Optics Design Plan SKA TDP Antenna Work Breakdown SKA TDP Baseline Antenna Optics. Summary

3. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Current SKA TDP Antenna

4. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Current SKA TDP Antenna

5. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Dishes + WBSPF Optics Design Plan

6. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optics Design Plan Detailed WBSP Feed characterization –Co-Pol and Cross-Pol Radiation Patterns –Gain –Input Matching –Losses –Phase Center Variations

7. National Astronomy and Ionosphere Center © Germán Cortés M 2008 WBSP Feed Far Field Radiation Pattern 10 GHz Co-Pol Dir = 10.11 dBi X-Pol -1.08 dBi

8. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optics Design Plan Detailed WBSP Feed characterization –Co-Pol and Cross-Pol Radiation Patterns –Gain –Input Matching –Losses –Phase Center Variations –Matching Optics Parameters

9. National Astronomy and Ionosphere Center © Germán Cortés M 2008 The SKA TDP Reflectors Symmetric ReflectorOff-Axis Reflector Possible Configurations Gregorian is Preferred

10. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optics Design Plan Antenna Analysis and Design Optimization –Co-Pol and Cross-Pol Radiation Patterns –Aperture Efficiency –Antenna Temperature vs. elev & freq –Aeff/Tsys Optimization Matching Optics for Different Configurations –Prime Focus –Secondary Focus Solutions –Multiple Focus Solutions

11. National Astronomy and Ionosphere Center © Germán Cortés M 2008  8m Reflector+Baseline Feed Far Field Radiation Pattern at 700 MHz Symmetric Reflector Co-Pol Symmetric Reflector X-Pol

12. National Astronomy and Ionosphere Center © Germán Cortés M 2008  6m Offset Reflector+Baseline Feed Far Field Radiation Pattern at 500 MHz Off-Axis Reflector Co-Pol Off-Axis Reflector X-Pol

13. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optics Design Plan Antenna Analysis and Design Optimization –Co-Pol and Cross-Pol Radiation Patterns –Aperture Efficiency –Antenna Temperature vs. elev & freq –Aeff/Tsys Optimization –Dynamic Range Issues: Far Side Lobe Levels Matching Optics for Different Configurations –Prime Focus –Secondary Focus Solutions –Multiple Focus Solutions

14. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Offset Design Prime Focus: Wide Pattern Wide Band Feed Freq= 1.400 GHz, f=5.2m Co-Polar Wide PatternX-Polar Wide Pattern -33.9 dB -14.2 dB -42.9 dB -40.8 dB -39.1 dB

15. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Far Field Radiation Patterns including Quadrupod Strut Diffraction Effects Wide Pattern 1.3 GHzWide Pattern 32 GHz -46 dB-126 dB  =178°  =82° -45 dB  =14° -85 dB  =106° -46 dB-152 dB  =180°  =82° -73 dB  =14° -123 dB  =106°

16. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optics Design Plan Antenna Analysis and Design Optimization –Co-Pol and Cross-Pol Radiation Patterns –Aperture Efficiency –Antenna Temperature vs. elev & freq –Aeff/Tsys Optimization –Dynamic Range Issues: Far Side Lobe Levels Matching Optics for Different Configurations –Prime Focus –Secondary Focus Solutions –Multiple Focus Solutions

17. National Astronomy and Ionosphere Center © Germán Cortés M 2008 The SKA TDP Reflectors Possible Configurations Gregorian Off-Axis

18. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optics Design Plan But,… In order to do this we need to agree in some initial parameters….

19. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Work Breakdown

20. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Mount SKA TDP Antenna Work Breakdown Reflector Pedestal Foundation Science Data Transport Optics UWB Feeds Monitoring & Control Power

21. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Work Breakdown Reflector Pedestal Foundation Mount UWB Feeds Optics Science Data Transport Monitoring & Control Power

22. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Work Breakdown Foundation Reflector UWB Feeds Optics Pedestal Mount Monitoring & Control Power Science Data Transport

23. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Work Breakdown UWB Feeds Optics

24. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Specification Frequency Aeff/Tsys Diameter Optics UWB Feeds

25. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Dishes+WBSPF Technology Paths Frequency 3c PHASE II AA’s 1.5 GHz 10 GHz 3a 3b 1 2 0.07 0.2 0.5 0.8 1.5 10 GHz AA’s Dishes Ø15m + WBSPF PAF’s Preliminary Specifications for the Square Kilometer Array v2.7.1 Dec. 4 2007

26. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Dishes+WBSPF Technology Paths Frequency 3c PHASE II AA’s 1.5 GHz 10 GHz 0.8 GHz 10 GHz 3a 3b 1 2 0.07 0.2 0.5 0.8 1.5 10 GHz AA’s Dishes Ø15m + WBSPF PAF’s Preliminary Specifications for the Square Kilometer Array v2.7.1 Dec. 4 2007

27. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Dishes+WBSPF Technology Paths Frequency 3c PHASE II AA’s 1.5 GHz 10 GHz 0.8 GHz 10 GHz 0.5 GHz 10 GHz3a 3b 1 2 0.07 0.2 0.5 0.8 1.5 10 GHz AA’s Dishes Ø15m + WBSPF PAF’s Preliminary Specifications for the Square Kilometer Array v2.7.1 Dec. 4 2007

28. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Dishes+WBSPF Technology Paths Frequency 3c PHASE II AA’s 1.5 GHz 10 GHz 0.8 GHz 10 GHz 0.5 GHz 10 GHz3a 3b 1 2 0.07 0.2 0.5 0.8 1.5 10 GHz AA’s Dishes Ø15m + WBSPF PAF’s 70% AA 30K Tsys 2400 3000 2000 N II Preliminary Specifications for the Square Kilometer Array v2.7.1 Dec. 4 2007

29. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Aeff/Tsys Point Source Sensitivity Aeff/Tsys [m 2 /K] 0.50.71.53.0 10.0 0.2 Preliminary Specifications for the Square Kilometer Array v2.7.1 Dec. 4 2007

30. National Astronomy and Ionosphere Center © Germán Cortés M 2008 0.50.71.53.0 10.0 0.2 SKA TDP Antenna Optics Aeff/Tsys Point Source Sensitivity Aeff/Tsys [m 2 /K] SKA TDP

31. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Tsys for a 15m Ø Dish,  A =70% 0.50.71.53.010.00.2 SKA TDP

32. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Tsys for a 15m Ø Dish,  A =70% 0.50.71.53.010.00.2

33. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Specification Frequency Aeff/Tsys Diameter   Optics Frequency 0.07 0.2 0.5 0.8 1.5 10 GHz 0.5 GHz 10 GHz UWB Feeds

34. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Specification Frequency Aeff/Tsys Diameter   Optics Frequency 0.5 GHz 10 GHz UWB Feeds 0.07 0.2 0.5 0.8 1.5 10 GHz

35. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Specification Frequency Aeff/Tsys Diameter   Optics Frequency 1.0 GHz 10 GHz 0.3 3 GHz Room Temp Cooled 0.5 GHz 10 GHz UWB Feeds 0.07 0.2 0.5 0.8 1.5 10 GHz 

36. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Specification Frequency Aeff/Tsys Diameter   Optics Frequency 1.0 GHz 10 GHz 0.3 3 GHz Room Temp Cooled 0.5 GHz 10 GHz UWB Feeds 0.07 0.2 0.5 0.8 1.5 10 GHz  6 8 10 12 14 16 Ø [m] 10 m  16 m

37. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Antenna Optics Specification Frequency Aeff/Tsys Diameter   Optics Frequency 1.0 GHz 10 GHz 0.3 3 GHz Room Temp Cooled 0.5 GHz 10 GHz UWB Feeds 0.07 0.2 0.5 0.8 1.5 10 GHz  6 8 10 12 14 16 Ø [m] 10 m  16 m Survey Speed Point Source Sensitivity

38. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Prime Focus Aeff/Tsys vs. Frequency for Na=4500 Reflector  12m Reflector  6m Reflector  8m

39. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Baseline Antenna Optics for Dishes + WBSPF

40. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Baseline Optics Design Plan Baseline Optics Designs that uses WBSPF Diameter: 12 m to 16 m Frequency: < 0.5 GHz to 10 GHz 1 st Step: Optimized Aeff/Tsys Optics Design for a Symmetric Configuration: –Prime Focus WBSPF: 0.3 GHz to 3 GHz –Secondary Focus WBSPF: 1 to 10 GHz 2 st Step: Optimized Aeff/Tsys Optics Design for a Off-axis Configuration

41. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optimized Prime Focus 16 m Diameter: 16 m WBSPF 0.3 to 3 GHz f 1 /D Optimized for for Aeff/Tsys 12 m

42. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Symmetric Antenna A eff /T sys Prime focus Optimization using UWB Feed (T A @45°, Trx=10K, Freq: 0.5 GHz to 2.5 GHz) 53°

43. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Symmetric Antenna A eff /T sys Prime focus Optimization using UWB Feed (T A @45°, Trx=10K, Freq: 0.5 GHz to 2.5 GHz) 53°64°79°

44. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optimized Prime Focus 16 m Diameter: 16 m WBSPF 0.3 to 3 GHz Optimized for for Aeff/Tsys: f 1 /D ~ 0.38 12 m

45. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optimized Secondary Focus 12 m Diameter: 12 m WBSPF 1 to 10 GHz Optimized for for Aeff/Tsys: f 2 /D > f 1 /D

46. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optimized Secondary Focus 12 m Diameter: 12 m WBSPF 1 to 10 GHz Optimized for for Aeff/Tsys: f 2 /D > f 1 /D Shaped Optics is also an option for this frequency band.

47. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA TDP Reflector + WBSP Feed Optimized Multiple Focus 16 m12 m Prime Focus Ø16 m WBSPF 0.3 to 3 GHz Optimized for for Aeff/Tsys: f 1 /D ~ 0.38 Secondary Focus Ø12 m WBSPF 1 to 10 GHz Optimized for for Aeff/Tsys: f 2 /D > f 1 /D

48. National Astronomy and Ionosphere Center © Germán Cortés M 2008 SKA Technology Path TDP WBSP Feeds Wide Band Feeds Sinuous/Gnd QSC Feed Chalmers Quad-Ridge ATA -7 dB -6 dB -14 dB Input Match -8 dB -10 dB 62° 66° 43°  10dB 65° 30K 45K TNTN 4 - 12 GHz 1 - 7 GHz >20:1 ~10:1 ~8:1 ~10:1 ~15:1 5:1 10:1 20:1 Bandwidth

49. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Summary We are proposing a Frequency coverage for the SKA TDP that goes from < 0.5 to 10 GHz, and that uses WBSPF + Dishes. TDP is going to provide two WBSP feeds that demonstrate the performance of these feeds: –One at room temperature from 0.3 to 3 GHz. –One Cooled feed from 1 to 10 GHz.

50. National Astronomy and Ionosphere Center © Germán Cortés M 2008 Summary Cont… We proposed a dish diameter between 12m to 16 m. And still have to agree in a dish diameter for the electromagnetic analysis. We are going to provide an antenna analysis and optimization for baseline symmetric and off-axis prime focus configurations that uses WBSP feeds. We are going to analyzed options for secondary or multiple focal point configurations. We are going to assess the issue of the far SLL for Dynamic Range.

51. National Astronomy and Ionosphere Center © Germán Cortés M 2008 End