Retrieval of equivalent currents by the use of an integral representation and the extinction theorem --- radome applications
Author
Summary, in English
The aim of this thesis is to solve an inverse source problem. The approach is based on an integral representation together with the extinction theorem. Both a scalar and a full-wave integral representation are implemented and solved by a Method of Moment procedure. The body of revolution enables usage of a Fourier transform to reduce the dimensions of the problem. A singular value decomposition is utilized to suppress singular values in the inversion process. A nose-cone radome is diagnosed by recreating the equivalent surface currents on its surface from measured near fields.
It is shown how the radome interacts with the field, creating beam deflection, pattern distortion, etc. The phase shift of the field due to the transmission through the radome, i.e., the insertion phase delay, is visualized. Disturbances due to defects, not detectable in the measured near field, are correctly localized by the equivalent surface currents. The alteration of side and flash lobes, together with the introduction of scattering due to the defects, are also visualized. Verification is made by comparison between the calculated and measured far field.
It is shown how the radome interacts with the field, creating beam deflection, pattern distortion, etc. The phase shift of the field due to the transmission through the radome, i.e., the insertion phase delay, is visualized. Disturbances due to defects, not detectable in the measured near field, are correctly localized by the equivalent surface currents. The alteration of side and flash lobes, together with the introduction of scattering due to the defects, are also visualized. Verification is made by comparison between the calculated and measured far field.
Publishing year
2010
Language
English
Full text
Document type
Licentiate thesis
Publisher
Department of Electrical and Information Technology, Lund University
Topic
- Electrical Engineering, Electronic Engineering, Information Engineering
Keywords
- extinction theorem
- inverse source problem
- integral representation
- radome diagnosis
- near-field transformation
Status
Published
Project
- Teorel: Radomes and frequency selective surfaces (FMV)
Research group
- Electromagnetic theory
Supervisor