A Microwave Quadruplexer (Correspondence)

In an earlier issue of these transactions Brown and Clark brought an unpublished phenomenon into discussion with their correspondence, "A Unique Solid-State Diplexer:" When a ferromagnetic oxide with small linewidth (yttrium-iron garnet substituted with aluminium in their experiments) is applied to a Y-junction circulator at a frequency lying just below the ferromagnetic resonance then circulation takes place in the opposite sense to that for a frequency just above the resonance.