Comments On "Line Width and Bandwidth of Millimeter-Wave Resonance Isolators" [Correspondence]

The writer cannot agree with some of the principal conclusions in the article by P. Vilmur and K. Ishii. The authors report a very narrow line width for a single crystal barium ferrite slab. The line width is very frequency sensitive, ranging from 3.5 oersteds at 58 Gc to 13 oersteds at 59 Gc. The authors derive a formula for line width which they claim fits the experimental data. However, it is believed that the narrow line width is not necessarily an intrinsic property of the material, but is influenced by the relatively large thickness of the slab used. Also this writer does not agree with the formula for line width derived by the authors.