Scattering by screw heads in reflecting surfaces and their effect on the sidelobes of reflector antennas
✍ Scribed by Jian Yang; Per-Simon Kildal
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 745 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0895-2477
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✦ Synopsis
Abstract
Screws are often used to fasten the main reflector of a reflector antenna to its support structure. The screw heads may then cause bumps in an otherwise smooth reflector surface. Thereby, they disturb the reflected fields and cause increased sidelobes. In this paper, a perturbation theory is introduced in order to calculate efficiently the increased sidelobes due to scattering from the screw heads. Screw heads are approximated as half spheres, whereby it becomes very efficient to calculate the scattering from them by using a spherical wave expansion algorithm, GIDMULT. This method has been verified by measurements in a low sidelobe antenna. We also describe some ways to reduce the scattering, such as dielectric coating of the screw heads and optimization of their locations. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 213–217, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11018