roma, 26/11/2007

Università di Napoli Federico IIDipartimento di Ingegneria Elettrica

SAS Project

Electromagnetic analysis of protection systems for airport structures

Ing. Dario Assante Contributors : Andrea G. Chiariello

Giovanni Miano Guglielmo Rubinacci

Luigi Verolino

Roma, 26/11/2007Roma, 26/11/2007

Università di Napoli Federico II - Dipartimento di Ingegneria Elettrica 2/27

What is radio-transparency?

Ideal condition

ground station

correct signal

correct direction


noisy signal

What is radio-transparency?

ground station

correct signal

…but some obstacles could interfere

wrong direction ?

?


Rules for the surrounding area

Different objects have to respect some distances not to interfere with the VOR signal


Characteristics of the Source

VOR navigation systemAlford antenna


Electromagnetic analysis

• Not possible to verify the radio-transparency of the barrier in real site• Not possible to reproduce the real radiation pattern of a VOR• Criteria to establish the distance between an object and the VOR are unknown

The behavior of the barrier is tested in a controlled place

The behavior of the barrier is numerically simulated


A finite-element numerical model

Finite-element numerical model with Comsol

CounterpoiseSource

Ground


A finite-element numerical model

Mesh Solution without obstacles

Dark lines: radiated power


Numerical results

Basement height: 2.5 mBasement height: 0.5 m

Dark lines: radiated powerDark lines: radiated power


Numerical results: radiated power


Anechoic chamber

receiving antenna

transmitting antenna


Anechoic chamber

Semi-anechoic chamber of the University of Naples Federico II

Length: 9.048 mWidth: 5.848 mHeight: 5.858 mFrequency: 26 Mhz - 18 Ghz

Can be turned into an anechoic chamber using mobile cones and ferrites


Anechoic chamber: the antennas


Measurements setup


Measure results: vertical polarization

-5

0

5

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25

100 200 300 400 500 600 700 800 900 1000

vuoto

0°

10°

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30°

40°

50°

Frequency [MHz]

Rec

eive

d po

wer

[dB

m]



0

5

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25

100 150 200 250 300 350 400

vuoto

0°

10°

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50°

Frequency [MHz]

Rec

eive

d po

wer

[dB

m]



-6

-5

-4

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0

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6

100 200 300 400 500 600 700 800 900 1000

0°

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Frequency [MHz]

Abs

orbe

d po

wer

[dB

m]


-6

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0

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100 150 200 250 300 350 400

0°

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Frequency [MHz]

Abs

orbe

d po

wer

[dB

m]



-3

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-1

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0 10 20 30 40 50

100 Mhz

150 Mhz

200 Mhz

250 Mhz

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350 Mhz

400 Mhz

Measure results: vertical polarizationA

bsor

bed

pow

er [

dBm

]

Angular position [Deg]


Measure results: horizontal polarization

-5

0

5

10

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20

25

100 200 300 400 500 600 700 800 900 1000

vuoto

0°

10°

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30°

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50°

Frequency [MHz]

Rec

eive

d po

wer

[dB

m]



10

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26

100 150 200 250 300 350 400

vuoto

0°

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50°

Frequency [MHz]

Rec

eive

d po

wer

[dB

m]


-8

-7

-6

-5

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-2

-1

0

1

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100 200 300 400 500 600 700 800 900 1000

0°

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20°

30°

40°

50°


Frequency [MHz]

Abs

orbe

d po

wer

[dB

m]


-8

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

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5

100 150 200 250 300 350 400

0°

10°

20°

30°

40°

50°


Frequency [MHz]

Abs

orbe

d po

wer

[dB

m]


-4

-3

-2

-1

0

1

2

3

0 10 20 30 40 50

100 Mhz

150 Mhz

200 Mhz

250 Mhz

300 Mhz

350 Mhz

400 Mhz

Measure results: horizontal polarizationA

bsor

bed

pow

er [

dBm

]

Angular position [Deg]


No appreciable effects has been measured in a wide range of frequencies

The barriers have to be tested in a real situation, but it’s reasonable to presume that no interference will be found

Anyway we suggest to place the basement of the barriers under the counterpoise of the VOR

Conclusions

roma, 26/11/2007

Documents