Abstract
A method is proposed for the measurement of phase shift and attenuation using a slotted line. These measurements enable the complex permittivity of isotropic films to be found by mounting the specimen longitudinally at the centre of a rectangular waveguide, the electric field being in the plane of the film. Experiments have been performed on films of Mylar and Teflon for a range of thicknesses from 75 to 250 mu m. The experimental results agree well with the accepted values (within approximately 2%).