A measurement of complex permittivity of lossy dielectrics by using flanged rectangular waveguide.

If it is possible to derive the complex permittivity of a dielectric material by measurement of the coefficient of reflection from the aperture of a flanged rectangular waveguide attached to a conductor-backed lossy dielectric sheet, an effective nondestructive measurement method can be established. In this paper, by solving simultaneous equations derived by an application of the spectral domain method, contour maps for derivation of the complex permittivity of a lossy dielectric from the reflection coefficient are formed and their characteristics are studied. The effectiveness of these contour maps is confirmed by experiments. In the region within the contour chart where the permittivity can be determined with good accuracy, it can be determined with an error of about 5% by means of a general-purpose network analyzer. Further, the attenuation of the electromagnetic wave within the lossy dielectric in the direction of propagation is studied in order to derive the dimensions of the sample and flange needed for actual measurement. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(4): 59–67, 2001 [ABSTRACT FROM AUTHOR]