A New Method for Measuring Anisotropy at Microwave Frequencies

A method for measuring electric or magnetic anisotropy at microwave frequencies is described. It is based on the effect produced by an anisotropic sample placed inside a square resonant cavity, on two originally degenerate and mutually independent modes. A coupling between the modes is created and, at the same time, the degeneracy is lifted and two distinct resonant frequencies appear. The theory of these effects is presented for the case of uniaxial anisotropic dielectrics. Experiments carried out with samples simulating anisotropy yielded results in good agreement with the theoretical predictions.