Measurements on Vivaldi v2 for AAVS0,
design considerations
G. Virone, A. Olivieri, A. Tibaldi, Z. Farooqui
O.A. Peverini, G. Addamo, R. Tascone
M. Piras°, A. Lingua°, A. Cina°, P. Maschio°, H. Bendea°
°DIATI, Politecnico di Torino
F. Perini*, M. Schiaffino*, J. Monari*, G. Bianchi *, S. Montebugnoli*
*Istituto di Radio Astronomia
Istituto Nazionale di Astro Fisica
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
Vivaldi v2
- Unbalanced 50 Ohm excitation
- Low cross pol on the principal axes
- No ground plane required
- Small size
- Metal-only
- Optical Self-powered element
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
AAVS0 Results – mutual coupling
Medicina, May 9th 2012
Ant1(Front) Ant2(Front)
0
Simulation (free space)
Simulation (Soil C)
Mesurement
Mutual Coupling in the H-plane (dB)
-5
-10
-15
-20
-25
Spacing 1.5 m
-30
-35
-40
-45
-50
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Frequency (GHz)
CNR IEIIT – Applied Electromagnetics Group
0.4
0.45
0.5
AAVP Progress Meeting,
Medicina, October 22-23 2012
AAVS0 Results – mutual coupling
Medicina, May 9th 2012
Ant1(Front) Ant2(Front)
Simulation (free space)
Simulation (Soil C)
Mesurement
Mutual Coupling in the H-plane (Deg)
150
100
50
0
-50
-100
-150
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Frequency (GHz)
CNR IEIIT – Applied Electromagnetics Group
0.4
0.45
0.5
AAVP Progress Meeting,
Medicina, October 22-23 2012
AAVS0 Results – mutual cross coupling
Ant1(Back) Ant2(Front)
-20
Simulation (free space)
Simulation (Soil C)
Mesurement
(Cross) Mutual Coupling (dB)
-30
-40
-50
Spacing 1.5 m
-60
-70
-80
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Frequency (GHz)
CNR IEIIT – Applied Electromagnetics Group
0.4
0.45
0.5
AAVP Progress Meeting,
Medicina, October 22-23 2012
AAVS0 Far-field Measurements
Embedded Element Pattern measurement in the operative conditions
120
R=10
D=1.5 m, R=2D2/
100
D=3 m, R=2D2/
D=4.5 m, R=2D2/
Distance (m)
80
D=6 m, R=2D2/
60
40
20
0
50
100
150
200
250
300
Frequency (MHz)
350
CNR IEIIT – Applied Electromagnetics Group
400
450
AAVP Progress Meeting,
Medicina, October 22-23 2012
Planar Scan Strategy
Normalized Total Station Data
100
AUT
Time
Time
Time
Time
50
0
Window
Window
Window
Window
1
1(interp)
2
2(interp)
NS: y (m)
Height=60 m
-50
AUT
-100
-150
-100
-50
0
50
EW: x (m)
100
150
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
Single Antenna Pattern @ 75 MHz
E-plane
H-plane
Fitting bewteen Measurement and Simulation
-25
-25
-30
-30
Received RF Power (dBm)
Received RF Power (dBm)
Fitting bewteen Measurement and Simulation
-35
-40
-45
-50
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-55
09:31:30
09:32:00
Time (HH:MM:SS)
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-35
-40
-45
-50
-55
19:03:00
19:03:30
Time (HH:MM:SS)
- Problems with TX instability
- TX spurious radiation
- Compass Accuracy
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
Single Antenna Pattern @ 150 MHz
E-plane
H-plane
Fitting bewteen Measurement and Simulation
Fitting bewteen Measurement and Simulation
-30
-30
-35
Received RF Power (dBm)
Received RF Power (dBm)
-35
-40
-45
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-50
-40
-45
-50
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-55
-60
-65
-55
-70
10:09:30
10:09:40
10:09:50
Time (HH:MM:SS)
10:10:00
CNR IEIIT – Applied Electromagnetics Group
10:07:30
Time (HH:MM:SS)
10:08:00
AAVP Progress Meeting,
Medicina, October 22-23 2012
Single Antenna Pattern @ 300 MHz
E-plane
H-plane
Fitting bewteen Measurement and Simulation
Fitting bewteen Measurement and Simulation
-35
-35
-40
Received RF Power (dBm)
Received RF Power (dBm)
-40
-45
-50
-55
-60
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-65
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-45
-50
-55
-60
-65
-70
-75
-70
09:06:45
09:07:00
Time (HH:MM:SS)
09:07:15
CNR IEIIT – Applied Electromagnetics Group
09:44:00
09:44:30
Time (HH:MM:SS)
AAVP Progress Meeting,
Medicina, October 22-23 2012
E-plane @ 450 MHz
Single antenna
3 x 3 Array (1.5 m spacing)
Fitting bewteen Measurement and Simulation
-50
-40
-55
-45
Received RF Power (dBm)
Received RF Power (dBm)
Fitting bewteen Measurement and Simulation
-60
-65
-70
-75
-80
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-85
10:34:15
Time (HH:MM:SS)
-55
-60
-65
-70
-75
-90
10:34:00
-50
10:34:30
CNR IEIIT – Applied Electromagnetics Group
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
08:56:45
08:57:00
Time (HH:MM:SS)
08:57:15
AAVP Progress Meeting,
Medicina, October 22-23 2012
H-plane @ 450 MHz
Single antenna
3 x 3 Array (1.5 m spacing)
Fitting bewteen Measurement and Simulation
Fitting bewteen Measurement and Simulation
-40
-50
-45
Received RF Power (dBm)
Received RF Power (dBm)
-55
-60
-65
-70
-75
-80
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-85
10:35:50
10:36:00
Time (HH:MM:SS)
10:36:10
-50
-55
-60
-65
-70
Measurement A (Raw Data)
Simulation A
Measurement B (Raw Data)
Simulation B
-75
-80
-85
-90
08:59:15
08:59:30
Time (HH:MM:SS)
08:59:45
We also measured the honeycomb version
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
New TX Unit for hexacopter
•
•
•
•
CNR IEIIT – Applied Electromagnetics Group
DDS Generator
4x Multiplier
External Programming
Good Symmetry
AAVP Progress Meeting,
Medicina, October 22-23 2012
Design activity
250
 =2
 =4
• Parametric Analyses
Width (mm)
– Width
– Length
– Aperture
– Inner Profile
– Outer Profile
 =6
200
Ellipse
150
100
50
0
0
100
200
300
400
500
600
700
800
900
Length (mm)
• Optimization runs (gradient, genetic)
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
Better matching
S11
0
W=1096, A=452, L=857, R=286, Rt=36, alpha=2, g=24, t=20, mL=55
W=1096, A=452, L=857, R=286, Rt=36, alpha=4, g=24, t=20, mL=55
W=1096, A=452, L=857, R=286, Rt=36, alpha=6, g=24, t=20, mL=55
ReferenceEllipse
-2
-4
-6
-8
-10
-12
-14
-16
-18
-20
0.05
0.1
0.15
0.2
0.25
0.3
0.35
frequency (GHz)
CNR IEIIT – Applied Electromagnetics Group
0.4
0.45
0.5
AAVP Progress Meeting,
Medicina, October 22-23 2012
Better symmetry of E- and H-planes
-3 dB angle; solid: DH/D(0) | dashed: DE/D(0) | "*": DH/DmaxH | "o": DE/DmaxE
150
W=1000, A=400, L=850, R=264, Rt=36, alpha=6, g=24, t=20, mL=55
W=1250, A=500, L=850, R=339, Rt=36, alpha=6, g=24, t=20, mL=55
W=1500, A=600, L=850, R=414, Rt=36, alpha=6, g=24, t=20, mL=55
ReferenceEllipse
100
50
0
0.2
0.25
0.3
0.35
frequency (GHz)
CNR IEIIT – Applied Electromagnetics Group
0.4
0.45
AAVP Progress Meeting,
Medicina, October 22-23 2012
No back lobe reduction
Vivaldi: the Back lobe reduction requires a narrower beam
SOLUTIONS
Open Boundary
TEM Horn
Quad Ridge Horn
• Possible Gridded version
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012
2
2
2
Aeff/Tsys [m /K]Aeff/Tsys [m /K]Aeff/Tsys [m /K]
QR Horn Aeff/Tsys
Number of elements = 0.5e6
5000
4000
3000
2000
1000
0
5000
4000
3000
2000
1000
0
5000
4000
3000
2000
1000
0
TantGnd = 11 K @ 450 MHz
Theta=0°
0.1
0.15
Zenith Viv v2
Zenith Horn
0.2
0.25
0.3
0.35
0.4
0.45
Eplane Viv v2
Hplane Viv v2
Eplane Horn
Hplane Horn
Theta=30°
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Eplane Viv v2
Hplane Viv v2
Eplane Horn
Hplane Horn
Theta=45°
0.1
0.15
0.2
0.25
0.3
Frequency (GHz)
CNR IEIIT – Applied Electromagnetics Group
0.35
0.4
0.45
AAVP Progress Meeting,
Medicina, October 22-23 2012
Conclusion
• AAVS0 goals have been reached in schedule
– Experimental results confirmed the computed data of
the Dual-Pol Vivaldi v2
• Mutual Coupling
• Embedded element pattern
• Vivaldi optimization
– Better matching
– High flexibility on main lobe shaping
– Improvement of the back lobe is in progress
CNR IEIIT – Applied Electromagnetics Group
AAVP Progress Meeting,
Medicina, October 22-23 2012