THE MICROWAVE GYRATOR 



17 



at the transition. Absorbing vanes, inserted in the circular section, 

 absorb this reflected component. The circular guide is placed in a solenoid 

 to establish an axial magnetic field along its length. 



The ferrite cylinders to be measured were placed at the mid-section 

 of the circular guide. When a cylinder was used which did not fill the 

 cross-section of the guide, it was supported along the axis of the guide 

 by means of a hollow polystyrene cylinder which did fill the guide. 



In addition to measuring the Faraday rotation, measurements of 

 insertion loss were made by determining the power transmitted under 

 identical conditions with the ferrite cylinder removed, and the ellipticity 

 of the transmitted wave was determined by measuring the power trans- 

 mitted when the rectangular guide on the detector side was rotated to 

 both positions of maximum and minimum transmission. Power trans- 

 mission measurements could be repeated within 0.2 db. Measurements 

 of the angle of rotation of the plane of polarization could be repeated 

 within 1° except in the region close to the gyromagnetic resonance where 

 rotations were large and ellipticity so great that it was difficult to decide 

 the positions of maximum and minimum transmission. These errors 

 increased up to the point where the transmitted wave was circularly 

 polarized where it was impossible to measure the angle of rotation. 



EXPERIMENTAL RESULTS 



Equation (25) indicates that the rotation per unit path length through 

 the ferromagnetic material is proportional to the magnetization of the 



CATHODE -RAY 

 OSCILLOSCOPE 



XTAL 

 DETECTOR 



(2K 



VARIABLE 

 ATTENUATOR 



J^ 



SIGNAL 

 OSCILLATOR 



^_1 



-/^ 



m 



BEAT 

 OSCILLATOR 



VARIABLE 

 ATTENUATOR 



TEST 

 CHAMBER 



^ 



AMPLIFIER 



DETECTOR 



(60 MC) 



VARIABLE 



I F 



ATTENUATOR 



METER 



VARIABLE 

 ATTENUATOR 



VARIABLE 

 ATTENUATOR 



VARIABLE 

 ATTENUATOR 



XTAL 

 CONVERTOR 



Fig. 5 — Experimental equipment set-up used to measure Farada}' rotations. 



