1360 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1953 



1400 



1600 



600 800 1000 



APPLIED FIELD IN OERSTEDS 



Fig. 15 — The dependence of the rotation characteristic upon the geometry 

 and dielectric constant of the surrounding medium. 



the ferrite element and upon the guide wavelength but that it is entirely 

 independent of the total length of the element. In Fig. 16 we show the 

 absorption of a positive circularly polarized wave as a function of applied 

 field for several cylinder diameters. We see that the first hump remains 

 relatively fixed in position while the second hump moves rapidly in the 

 direction of higher fields and becomes larger in height as the diameter 

 is increased. The first resonance is the ferromagnetic resonance, and its 

 movement with increasing diameter is due simply to the fact that the 

 demagnetizing factors of the cylinder are changed when the diameter 

 is changed. The movement of the second hump can be explained if we 

 assume that the resonance frequency of the shape resonance is given by 

 an equation of the form 



/ 



^Vm? 



(20) 



This is an equation typical of those encountered in dimensional reso- 

 nances. Here A is some constant associated with the geometry of the 

 sample and d is the cylinder diameter. At a fixed frequency, we see that 



