Material sheets have been characterized for dielectric properties using the Vector network analyzer based freespace method. The VNA has been calibrated through Thru -Reflect -Line technique by realizing the free space standards in 8.2–12.4 GHz frequency range. Complex permittivity has been evaluated for Teflon sheet of 0.675 cm thickness placing between two antennas and for validation of the set up. In the same manner the dielectric constant of Plaster of Paris (CaSO4·H2O) was determined in the range of 2.26 to 2.50 over the measured frequency range. The uncertainties in the dielectric constant, loss factor and loss tangent were evaluated at spot frequencies using the derived expressions based on the factors associated with S-parameter measurements, operating frequency and thicknesses of samples. The present study will be very useful for determining the dielectric properties of newly developed materials in a sheet form at microwave frequencies.
Dielectric properties, plaster of Paris, measurement uncertainty, calibration, S-parameters
