A wide-band nonreciprocal TEM-transmission-line network

This nonreciprocal TEM-mode network consists basically of a parallel arrangement of two conductors and a ferrite rod within a grounded outer conductor. The conductors are connected in a two-port configuration providing, in the absence of the ferrite rod, complete isolation from zero frequency to the cutoff frequency of the first higher mode. With an unmagnetized ferrite rod properly inserted, the broadband isolation is virtually unaffected. When the rod is magnetized by an axial magnetic field, coupling occurs between the two ports by a process analogous to Faraday rotation. The device may be used as a broad-band gyrator, switch, or modulator, and with the addition of a resistanee card as an isolator. The bandwidth of these components is inherently limited only by the bandwidth capability of the ferrite material itself.