1350 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1953 



20 



16 



^ 12 



UJ 



oi 



a. „ 

 o 8 



UJ 



o 

 ? 4 



z 



1260 1680 2100 



FIELD CURRENT IN OERSTEDS 



2520 



2940 



3360 



Fig. 8 — Rotation of the plane of polarization and absorption of the positive 

 component as functions of applied dc field for a wave propagating through a 

 waveguide containing a very small cylinder of ferrite. The inflection of 2,400 

 oersteds is due to a "cavity resonance" as discussed later. 



the waveguide the cutoff wavelength is increased because the effective 

 value of € is increased. If the ferrite cylinder is quite small this alteration 

 will be unimportant, but if the diameter of the rod exceeds about one- 

 quarter that of the air filled dominant mode guide this mechanism can 

 lead to the existence of higher order modes for the negative component. 

 When this happens the plane wave theory obviously cannot be expected 

 to apply, for the presence of multiple modes in the propagation of either 

 component will introduce an additional variable not present in the plane 



