The relative complex permittivity can be extracted with time domain data from a perfect electrical conductor (PEC) backed sample of a low-loss, non-dispersive dielectric using dual ridged waveguide aperture probes with attached PEC flange plates of the same geometry and different dimensions. The temporal domain measurement of interest is the ability to detect the reflection from the edge of the flange plate in the parallel region created by the flange plate and the PEC backing on the dielectric sample. Signal processing windows are applied to the data in order to exploit this edge reflection. The types of signal processing methods used and the geometry and size of the flange plate help identify the edge reflection. Measurements are taken using square and circular flange plates of different dimensions. Measured data is then processing using Kaiser and Blackman-Harris windows to show the edge reflection. A simple extraction technique for the permittivity is used and compared with industry standard values
