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Effects of Curved Wavefronts on Conductor-Backed Reflection-Only Free-Space Material Characterization Techniques.
Raenita A Fenner1, Edward J Rothwell2
1Loyola University Maryland, Baltimore, MD 21210, USA.
International Scholarly Research Notices
|June 28, 2016
Summary
Wavefront curvature causes errors in free-space material characterization. This study analyzes the impact of curvature on the two-thickness method, comparing plane waves and line sources for accurate material property extraction.
Area of Science:
- Electromagnetics and Material Science
- Wave Propagation and Optics
Background:
- True plane waves are difficult to achieve in experimental settings.
- Wavefront curvature is a source of systematic error in free-space material characterization.
- Accurate determination of electric permittivity and magnetic permeability is crucial for various applications.
Purpose of the Study:
- To perform an error analysis of wavefront curvature's impact on the two-thickness free-space method.
- To compare the accuracy of extracted electric and magnetic permeability using plane wave versus line source approximations.
- To investigate these effects for both transverse electric (TE) and transverse magnetic (TM) polarizations.
Main Methods:
- Utilized the two-thickness free-space measurement technique.
- Simulated and analyzed the effects of wavefront curvature on material parameter extraction.
- Compared results obtained using idealized plane wave models against those derived from line source models.
- Evaluated performance for low-loss dielectric and magnetic radar-absorbing materials.
Main Results:
- Quantified the systematic error introduced by wavefront curvature in free-space material characterization.
- Demonstrated significant differences in extracted electric and magnetic permeability values between plane wave and line source models.
- Identified the dependence of these errors on the type of source (plane wave vs. line source) and polarization (TE vs. TM).
Conclusions:
- Wavefront curvature significantly affects the accuracy of free-space material characterization, particularly with the two-thickness method.
- Line source models may offer a more realistic representation than plane wave models in certain experimental conditions.
- Careful consideration of wavefront effects is necessary for precise determination of electromagnetic properties.
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