A spectrometer method for measuring the electrical constants of lossy materials

The analysis of the propagation of a plane wave at oblique incidence through a strip of lossy material is stated, the behaviour of the lossy material being completely represented by the use of a complex refractive index and a complex reflection coefficient. A measurement technique is described whereby these constants can be measured from a strip of material used in a 1 cm parallel-plate spectrometer. The analysis and measurement technique are checked by the application of the spectrometer method and the established waveguide method to the measurement of two ordinary lossy dielectrics. The spectrometer method may be used for the measurement of any homogeneous material, and is especially suitable for the examination of anisotropic artificial dielectrics. The accuracy of the method is discussed for the measurement of the electrical constants of medium-loss materials with refractive indices between 0.5 and 2.0.