CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
AAVS0 Results, Dual-Polarized Vivaldi Antenna
G. Virone, R. Tascone, A. Olivieri, O.A. Peverini, G. Addamo
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, Dwingeloo, December 12-16 2011
Dual-pol Vivaldi 50 Ohm ver1
• Maximum size 1.1 m
• Metal-only
• 50 Ohm unbal impedance
• No additional ground plane
• Very Low Cross-Pol
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Feed Configuration and LabelingFront Probe
Back Probe
Housing for Electronics
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Manufacturing
Laser cutter
-First Prototype-Laser cutting machine-Multi-layer alluminum prototype
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
VNA Reflection Measurement
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
Frequency (GHz)
Ref
lect
ion
(dB
)Reference Impedance = 50 Ohm
Back Probe (Sim)Front Probe (Sim)Back Probe (Meas)Front Probe (Meas)
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Radiation Pattern Measurements
-100 0 100-30
-20
-10
0
10H-plane @70 MHz
Theta (Deg)
Nor
mal
ized
Gai
n (d
B)
-100 0 100-30
-20
-10
0
10E-plane @70 MHz
Theta (Deg)
Nor
mal
ized
Gai
n (d
B)
-100 0 100-30
-20
-10
0
10H-plane @180 MHz
Theta (Deg)
Gai
n (d
B)
-100 0 100-30
-20
-10
0
10E-plane @180 MHz
Theta (Deg)
Gai
n (d
B)
-100 0 100-30
-20
-10
0
10H-plane @450 MHz
Theta (Deg)
Gai
n (d
B)
-100 0 100-30
-20
-10
0
10E-plane @450 MHz
Theta (Deg)
Gai
n (d
B)
Outdoor Elevated Antenna Test Range (Turin, July 2011)
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
From Version 1 to Version 2
Good matching in the 70-450 MHz band
High back lobe
Low directivity at 45° in E-plane
Acceptable matching in the 70-450 MHz band
Lower back lobe
Higher directivity in the ±45° sky coverage
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Vivaldi Aeff/Tsys for each polarization
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.450
1000
2000
3000
Frequency (GHz)
Aef
f/Tsy
s [m
2 /K]
Number of elements = 1e6
Zenith v1Zenith v2
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.450
1000
2000
3000
Frequency (GHz)
Aef
f/Tsy
s [m
2 /K]
Eplane 45 Deg v1Hplane 45 Deg v1Eplane 45 Deg v2Hplane 45 Deg v2
Theta=0°
Theta=45°
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Effect of the Soil
0.1 0.2 0.3 0.4 0.5
4
6
8
10
12
Frequency (GHz)
Per
mitt
ivity
(Rea
l Par
t)
Soil ASoil BSoil C
0.1 0.2 0.3 0.4 0.50
0.02
0.04
0.06
0.08
0.1
Frequency (GHz)
Con
duct
ivity
(S/m
)
Soil ASoil BSoil C
ICRAR Soil DATA
-150 -100 -50 0 50 100 150-30
-25
-20
-15
-10
-5
0
5
10
Theta (Deg)
Dire
ctiv
ity (d
B)
Directivity @ 100 MHz (H-plane)
-150 -100 -50 0 50 100 150-30
-25
-20
-15
-10
-5
0
5
10
Theta (Deg)
Dire
ctiv
ity (d
B)
Directivity @ 450 MHz (H-plane)
0.1 0.2 0.3 0.4 0.5-30
-25
-20
-15
-10
-5
0
Frequency (GHz)
Ref
lect
ion
Coe
ffici
ent (
dB)
Free SpaceSoil ASoil BSoil C
Radiation Efficiency = 0.7
Rad. Eff. = 0.92
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
50
100
150
200
250
300
Frequency (GHz)
Noise
Temp
eratur
e (K)
Soil A (Full Wave)Soil B (Full Wave)Soil C (Full Wave)TantGnd (Far-Field)TantSky (Far-Field)
Computation of TantGnd
Tantgnd = T0 (1-ηR)T0 = 290 K
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Gain vs Frequency
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45-10
-8
-6
-4
-2
0
2
4
6
8
10
Frequency (GHz)
Gai
n (d
B)
BroadBand Gain (dB)
Free SpaceSoil B
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Hexacopter Far-Field Measurements (1)
http://www.mikrokopter.de
Telemetry and GPS
RF TX and additional battery
Collaboration with DITAG, Politecnico di Torino
Hexacopter Battery
Bow-tie antenna
Optical Scatterer
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Hexacopter (2)• FF Pattern measurement in
the operative condition (ground, small array)
• Meas. range > 60 m• GPS Accuracy : 0.5 m-> 1 cm• Total Station Accuracy: 5 mm
• GPS-sync spectrum analyzer
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Low-cost Manufacturing
Target Cost200€ x
antenna
Mini-production of (48) Vivaldi, with 2cm honeycomb (used for High speed NL trains)
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Optical Self-Powered Vivaldi
BATTERY
- Galvanic isolation between FE and DS - more stable amplitude&phase Vs temperature - RFI immunity (self-shielded)- no Gain disequalization- no Power Distribution no DC power losses- easy-deployable (no buried FO)
Front End
That area could be sufficient,but we need more investigation and tests on the field.Thin film (amorphous silicon )
We have 0.15 m2 maximum available area per arm.
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
Conclusion
• Experimental results confirmed the computed data of the Dual-Pol Vivaldi v1.
• An improved version (v2) has been designed (AAVS0) and manufactured (4 x 4 array)
• Simulations of the soil ground effect confirm the performance (without additional mesh)
• A new measurement setup is being developed• Industrialization process is in progress• Optical Self-powered element
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
3 x 3 Regular Array Simulation
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-40
-35
-30
-25
-20
-15
-10
-5
0
Frequency (GHz)
Ref
lect
ion
& C
oupl
ing
(dB
)Reference Impedance = 50 Ohm
Reflection Coeff. (single element)Reflection Coeff. (embedded element)Mutual Coupling H-planeMutual Coupling E-plane
Element Spacing is 1.5 m
CNR IEIIT – Applied Electromagnetics Group AAVP, Dwingeloo, December 12-16 2011
VNA Coupling Measurement
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
Frequency (GHz)
Cro
ss C
oupl
ing
betw
een
ports
(dB
)Reference Impedance = 50 Ohm
SimulatedMeasured