Unusual Waveguide Characteristics associated with the Apparent Negative Permeability obtainable in Ferrites

Abstract

B AND H in a magnetized ferrite material are related, not by a scalar permeability, but by a tensor of the form: where z is the direction of the magnetization¹. If a plane wave is propagated along the z direction and is circularly polarized, the permeability associated with the transverse components in the xy plane assumes the form: where the sign depends on the direction of the circular polarization. In many ferrites at 10,000 Mc./s., k is greater than µ and the effective permeability for right-handed polarization about the field direction is negative. The propagation constant, which is proportional to the square root of the permeability, is imaginary and the wave is evanescent.