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Field Coupling into the A380 Aircraft. Dietmar Leugner, H.-D. Brüns leugner@tu-harburg.de bruens@tu-harburg.de. 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
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Field Coupling into the A380 Aircraft Dietmar Leugner, H.-D. Brüns leugner@tu-harburg.de bruens@tu-harburg.de • 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
Introduction • Fully discretized MoM model • 10219 unkowns • Typical element dimensions from2 cm² to 2500 cm²
Introduction • Loop antenna, HF range • Numerically critical becauseof very low radiationresistance • Stable solution only withinserted wire grid • Validation: power budget
Typcal results for the HF range (A380) Radiation diagram at 30 MHz Loop antenna input impedance
Transition slot / conducting part(problem of end charges) Possible solution: overlap and inclusion of into the system matrix as impressed current (to be done)
Illuminated sphere at 300 MHz Geometry Field vectors in log. scale
Discretization of back door (1) Surface currents at 30 MHz Door: 0.9m x 1.9m Slot width: 1 cm
Discretization of back door (2) Details of slot discretization
Failure of classical EFIE (1MHz, 0°) Cross section of empty aircraft Closed Model Model with door
E field at 1 MHz generated by magnetic currents (phase 0°) Cross section of empty aircraft Vectors are plotted in log. scale
E field caused by magnetic slot currents 30 MHz 1 MHz Maximum magnitude of E in cross section of empty aircraft Aircraft structure completely neglected
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