.4 NEW MICROWAVE TRIODE 



543 



In some of the experimental tubes, bandwidths to the half power points 

 of 21 mc to 250 mc have been measured. Typical of one of the better 

 tubes, though not the best one, are the data contained in Fig. 17. The 

 bandwidth of the input circuit is about twice that of the output circuit, 

 and the SWR slumps outside the band on the low frequency side. The 

 output impedance is more regular, exhibiting the familiar standing wave 



m 10 



CE 6 



3940 3980 4020 4060 4100 4140 



FREQUENCY IN MEGACYCLES PER SECOND 



Fig. 17. — Input and output standing wave ratio versus frequency. 



■^ a 



^ 6 

 < 



3980 4020 



FREQUENCY IN 



4060 4100 4140 



MEGACYCLES PER SECOND 



Fig. 18. — Transmission characteristic of a one-stage ampiitier. 



ratio of a simple single tuned resonant circuit. When the output impe- 

 dance is plotted on the Smith reflection coefficient chart, the circle which 

 results is also similar to that of a single tuned circuit. This is desirable 

 since it then becomes a simple matter to incorporate the plate circuit in 

 a maximally-flat filter of as many resonant branches as are needed, in 

 the same way that the modulator output circuit was treated. 



The transmission bandwidth for this single stage amplifier was 203 mc 

 to the half power points, as shown in Fig. 18. This, with a gain of 8.05 db 



