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ALMA front-end beam efficiency evaluation. A.M. Baryshev NOVA/SRON/RuG. Outline. band 9 optics measurement system (example) Band 9 efficiency analysis NA FEIC data for band 9 and band 7 Q/A. The beam pattern measurement Set-Up. Typical near field measurements. Amplitude. Phase. - PowerPoint PPT Presentation
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Mitaka, 27 Feb 2008
ALMA front-end beam efficiency evaluation
A.M. BaryshevNOVA/SRON/RuG
Mitaka, 27 Feb 2008
Outline
• band 9 optics measurement system (example)
• Band 9 efficiency analysis
• NA FEIC data for band 9 and band 7
• Q/A
Mitaka, 27 Feb 2008
The beam pattern measurement Set-Up
Mitaka, 27 Feb 2008
Typical near field measurements
PhaseAmplitude
Mitaka, 27 Feb 2008
Far field beam patterns
80% typical aperture
efficiency
Mitaka, 27 Feb 2008
620 640 660 680 700FrequencyGHz
75
80
85
90
95
100edutilpmA
ycneiciffe%
P1
P0
Aperture Efficiency
No central blockage
Mitaka, 27 Feb 2008
Beam pointing I
620 640 660 680 700FrequencyGHz
1
0.8
0.6
0.4
0.2
0
0.2
maeB
elgnaged P1 Y tilt
P0 Y tilt
P1 X tilt
P0 X tilt
Mitaka, 27 Feb 2008
Beam pointing II
-3 -2 -1 1 2 3
-4
-3
-2
-1
1
2 X and y axes are beamoffsets in degrees
Red – Pol 0Green Pol 1Blue secondary mirrorangular dimensions
Mitaka, 27 Feb 2008
Focus offset (x,y)
620 640 660 680 700FrequencyGHz3
2
1
0
1
2sucoF
noitisopmm
P1 YP0 YP1 XP0 X
Mitaka, 27 Feb 2008
Beam squint
Mitaka, 27 Feb 2008
Defocus
620 640 660 680 700FrequencyGHz
60
70
80
90
100
110
120
sucoF
noitisopmm P1 Z
P0 Z
Mitaka, 27 Feb 2008
Co-polar
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Cross -polar
-19dB peak, -18dB total power
Mitaka, 27 Feb 2008
Far field cross pol ratio
90 95 100 105 110 115
90
95
100
105
110
115
Red = -10dB4 dB contour
Mitaka, 27 Feb 2008
NA FEIC data b9, near fieldNRAO FE1 band9 2007-11 Scan 77 FF SINGLE BEAM.txt
-20 0 20 40X displacement (mm)
-40
-20
0
20
40
)m
m( tnemecalpsid
Y
)Bd( edutilp
mA detcete
D
0. -5. -10. -15. -20. -25. -30. -35. -40. -45. -50. -55. -60. -65. -70. -75. -80. -85. -90. -95.-100.-105.-110.-115.-120.
-20 0 20 40X displacement (mm)
-40
-20
0
20
40
)m
m( tnemecalpsid
Y
)ged( esahP detcete
D
-180.
-150.
-120.
-90.
-60.
-30.
0.
30.
60.
90.
120.
150.
180.
Lambda/4 compensation off
Mitaka, 27 Feb 2008
NA FEIC data b9, near field
NRAO FE1 band9 2007-11 Scan 77 FF Both BEAMS .txt
-20 0 20 40X displacement (mm)
-40
-20
0
20
40
)m
m( tnemecalpsid
Y
)Bd( edutilp
mA detcete
D
0. -5. -10. -15. -20. -25. -30. -35. -40. -45. -50. -55. -60. -65. -70. -75. -80. -85. -90. -95.-100.-105.-110.-115.-120.
-20 0 20 40X displacement (mm)
-40
-20
0
20
40
)m
m( tnemecalpsid
Y
)ged( esahP detcete
D
-180.
-150.
-120.
-90.
-60.
-30.
0.
30.
60.
90.
120.
150.
180.
Lambda/4 compensation needs to be looked at
Mitaka, 27 Feb 2008
NA FEIC b9 far field
Aperture efficiency 63.3%, Phase center X, Y, Z: 1.32, -0.83, 289 (mm) (0,-0.94) Deg
-15 -10 -5 0 5 10 15 20X angle (Deg)
-15
-10
-5
0
5
10
15
)geD( elgna
Y
NRAO FE1 band9 2007-11 Scan 77 FF SINGLE BEAM.txt
)Bd( edutilp
mA detcete
D
0. -4. -8. -12. -16. -20. -24. -28. -32. -36. -40. -44. -48. -52. -56. -60. -64. -68. -72. -76. -80.
{0.003, -1.4}
-10 -5 0 5 10X angle (Deg)
-10
-5
0
5
10
)geD( elgna
Y
NRAO FE1 band9 2007-11 Scan 77 FF SINGLE BEAM.txt
)Bd( edutilp
mA detcete
D
0.
-4.
-8.
-12.
-16.
-20.
-24.
-28.
-32.
-36.
-40.
-44.
-48.
-52.
-56.
-60.
-64.
-68.
-72.
-76.
-80.
{0.003, -1.4}
Aperture efficiency 65.1%, Phase center X, Y, Z: 1.32, -0.87, 292 (mm) (0, -1.40) Deg
Probe model: OEWG WR22: 33.00-50.00 GHz ?
Mitaka, 27 Feb 2008
NA FEIC b7 data, near field
NRAO FE1 Band7 2007 Scan 39 Nearfield.txt
-60 -40 -20 0 20 40 60 80X displacement (mm)
-60
-40
-20
0
20
40
60
)m
m( tnemecalpsid
Y
)Bd( edutilp
mA detcete
D
0. -5. -10. -15. -20. -25. -30. -35. -40. -45. -50. -55. -60. -65. -70. -75. -80. -85. -90. -95.-100.-105.-110.-115.-120.
-60 -40 -20 0 20 40 60 80X displacement (mm)
-60
-40
-20
0
20
40
60
)m
m( tnemecalpsid
Y
)ged( esahP detcete
D
-180.
-150.
-120.
-90.
-60.
-30.
0.
30.
60.
90.
120.
150.
180.
Mitaka, 27 Feb 2008
NA FEIC b7 data, far field
-20 -10 0 10 20X angle (Deg)
-20
-10
0
10
20
)geD( elgna
Y
NRAO FE1 Band7 2007 Scan 39 Nearfield.txt
)Bd( edutilp
mA detcete
D
0.
-4.
-8.
-12.
-16.
-20.
-24.
-28.
-32.
-36.
-40.
-44.
-48.
-52.
-56.
-60.
-64.
-68.
-72.
-76.
-80.
{1., -0.51}
-10 -5 0 5 10X angle (Deg)
-10
-5
0
5
10
)geD( elgna
Y
NRAO FE1 Band7 2007 Scan 39 Nearfield.txt
)Bd( edutilp
mA detcete
D
0.
-4.
-8.
-12.
-16.
-20.
-24.
-28.
-32.
-36.
-40.
-44.
-48.
-52.
-56.
-60.
-64.
-68.
-72.
-76.
-80.
{1., -0.51}
Aperture Efficiency 42.9, Phase center X,Y,Z -- 2.22, 5.92, 103.84 (mm)
