Comparison of dielectric properties using metal-backed and transmission reflection method / Jane Jaong

This paper presents free-space measurements on metal-backed samples and planar samples such as teflon, polyvinyl-chloride (PVC), polypropylene (PP), polyethylene (PE) and nylon in free-space. This free-space measurement is conducted m an anechoic chamber and operated in the frequency range of 8.0-12.5 GHz. For metal-backed samples, loss tangents are calculated from the measured reflection coefficient, S11. As for the planar samples, complex permittivity and complex permeability can be calculated from the measured reflection and transmission coefficient S11 and S21. The measurement system consist of transmit and receive horn lens antennas, Wiltron Vector Network Analyzer, mode transitions, printer and coaxial cables. Diffraction effects at the edges of the samples are minimized by using spot-focusing horn lens antennas. Errors due to the multiple reflections between antennas and via the surface of the sample are eliminated by performing a free space LRL (Line, Reflect, Line) calibration technique.