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Cross Range Smear Characterization In Xpatch Isar Images, Peter E. Muend
Cross Range Smear Characterization In Xpatch Isar Images, Peter E. Muend
Theses and Dissertations
This thesis investigates a cross range smear phenomenon seen in far field, frequency domain Xpatch calculations. The phenomenon is very subtle, manifesting itself in 2-D ISAR images as a low-level scatterer response smeared in the cross range direction. This cross range smear occurs only using complex target models with certain characteristics. It is also a mathematical construct, not occurring in physical SAR systems. Using a carefully constructed scattering target set, Xpatch-generated ISAR images are used to characterize cross range smear in terms of its input parameters. The characterization is done as a DOE-based polynomial approximation to the observed smear levels. …
Stepped Waveguide Electromagnetic Material Characterization Technique, Sean P. Dorey
Stepped Waveguide Electromagnetic Material Characterization Technique, Sean P. Dorey
Theses and Dissertations
Electromagnetic material characterization is the process of determining the complex permittivity and permeability of a material. A new waveguide material measurement technique is developed to reduce test sample size requirements for low-frequency applications. Specifically, a waveguide sample holder having a reduced aperture is utilized to decrease the time and cost spent producing large precision test samples. This type of sample holder causes a disruption in the waveguide-wall surface currents that results in the excitation of higher-order modes. This thesis will demonstrate how these higher-order modes can be accommodated using a modal-analysis technique, thus resulting in the ability to measure smaller …