aavs0 results, dual-polarized vivaldi antenna

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


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


Feed Configuration and LabelingFront Probe

Back Probe

Housing for Electronics


Manufacturing

Laser cutter

-First Prototype-Laser cutting machine-Multi-layer alluminum prototype


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)


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)


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


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°


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


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


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


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


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


Low-cost Manufacturing

Target Cost200€ x

antenna

Mini-production of (48) Vivaldi, with 2cm honeycomb (used for High speed NL trains)


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.


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


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


Reflection Coeff. (single element)Reflection Coeff. (embedded element)Mutual Coupling H-planeMutual Coupling E-plane

Element Spacing is 1.5 m


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


SimulatedMeasured

aavs0 results, dual-polarized vivaldi antenna

Documents