Faraday Rotatation in Ferrites
A plane circularly polarised wave propagating in Ho direction will have two different propagation constants given by
Figure : Faraday Rotation in Ferrites
Therefore, for a linearly polarised wave propagating along H0, the plane of polarisation rotates. This phenomenon is a non-reciprocal one. The rotation of the elec- tric field of a linearly polarised wave passing through a magnetised ferrite is known as Faraday rotation as explained above with Figure.
Let a linearly polarised TEM wave propagates in Ferrite along the Z-axis with
The linearly polarised wave may be decomposed into the sum of clockwise and anti-clockwise circularly polarised waves. The component waves propagate with different phase constants β and β- respectively, and the two corresponding electric field vectors rotate at different rates. Over a distance A, the resultant linearly polarised wave will undergo a phase delay of
and corresponding rotation angle.
The rotation per unit distance is
This property is utilised in designing ferrite isolator and circulators.