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Field Coupling into the A380 Aircraft

Introduction

The field equivalence principle

Special consideration for slots

Demonstration by means of a small example

Numerical model of the A380 aircraft with back doors

Fully discretized model, EFIE problem

Coupling-in results based on the application of equivalent currents of magnetic type

Conclusion

Dietmar Leugner, H.-D. Brünsleugner@tu-harburg.debruens@tu-harburg.de

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Introduction

Fully discretized MoM model

10219 unkowns

Typical element dimensions from2 cm² to 2500 cm²

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Introduction

Loop antenna, HF range

Numerically critical becauseof very low radiationresistance

Stable solution only withinserted wire grid

Validation: power budget

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Typcal results for the HF range (A380)

Radiation diagram at 30 MHz

Loop antenna input impedance

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Huygens principle in electromagnetics

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Transition slot / conducting part(problem of end charges)

Possible solution:

overlap

and inclusion ofinto the system matrix as impressed current (to be done)

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Illuminated sphere at 300 MHz

Field vectors in log. scaleGeometry

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Coupled-in E field

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Discretization of back door (1)

Door: 0.9m x 1.9mSlot width: 1 cm

Surface currents at 30 MHz

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Discretization of back door (2)

Details of slot discretization

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Failure of classical EFIE (1MHz, 0°)

Closed Model Model with door

Cross section of empty aircraft

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E field at 1 MHz generated by magnetic currents (phase 0°)

Vectors are plotted in log. scale

Cross section of empty aircraft

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E field caused by magnetic slot currents

Maximum magnitude of E in cross section of empty aircraft Aircraft structure completely neglected

1 MHz 30 MHz

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Conclusion

Small slots in large conducting bodies cannot be treated sufficiently by a MoM-EFIE approach

Equivalent currents in slots and apertures acting as excitation sources provide an alternative

Special treatment at the intersecting line of Huygens surfaces and MoM surfaces is necessary

Application of purely magnetic slot currents give a first order solution

The method works only if completely decoupled spaces are considered