A Methodology for Determining the Level and Nature of Scattering from Measurements of Material Samples in RF Propagation Modeling: System Calibration at 3.5GHz

For accurate RF propagation modeling, material parameters must be realistically determined for tools like Ray Tracing. This paper presents a reliable method for measuring RF scattering by sample materials and outlines the process for deriving usable modeling parameters. Traditional reliance on conductive and dielectric properties alone can lead to accuracy issues at higher frequency. The method is, however scalable across frequencies, with a focus on 3.5 GHz. It accommodates small-dimension samples, with calibration being a critical component. The paper emphasizes calibration using a flat metal plate $(34 \mathrm{~cm}$ $\mathrm{x} 17 \mathrm{~cm}$) and highlights key outcomes used to discern the scattering behavior of various materials based on gain, beamwidth, and sidelobe levels. The results closely match theoretical expectations for a uniformly illuminated metal sheet, with a beamwidth ranging approximately $40^{\circ}-50^{\circ}$, sidelobe levels below $11 \mathrm{~dB}$ than the main beam, and a cross-polarization ratio (XPR) around 18-20 dB. This data enhances RF propagation modeling.