Comments on "A Nonreciprocal Circular Polarizer" (Correspondence)

In the above-named work [ibid., vol. MTT-15, pp. 37-41, Jan. 1967] the author described two models of a nonreciprocal circular polarizer. The second model was a two-stage device in which the second stage provided a refinement of the approximate circular polarization produced by the first stage. The device used for this purpose consisted of a circular waveguide with a ferrite rod along its axis, so dimensioned that one sense of circular polarization could propagate but not the other. It has been called to the author\´s attention that a theoretical basis for such a device was provided in a series of papers by R.A. Waldron ("Electromagnetic wave propagation in cylindrical waveguides containing gyromagnetic media," J. Brit. IRE, vol. 18, pp. 597-612, 677-690, 733-746, 1958). Furthermore, a patent embodying the applicacation of this principle was obtained by him (British Patent 850 054, September 2S, 1960).