11-7] THE PLATINOTRON 603 



Signal 



Cathode 



Output 





\- Terminating 

 Slow Wave Structure \ Resistance 



/ ^ 



"^msMms^^Mmi,------^ 



L D '\ -r- — -. ^ WW 



y" \ Direction of / 



4node \ Magnetic Field ^'Collector 



Electron Beam 

 Fig. 11-29 Axial-Field Backward Wave Oscillator — Type-0 Carcinotron. 



Signal 

 Output 



Anode 



Slow Wave Structure 



Terminating 

 Resistance - 



A WW 



injiTLryiJixy^Jini ^ 



/ ^Flprtrnn \ m ^- or ^Collector 



Cathode ^Beam ^Negative Sole geam 



Magnetic Field Normal to Page 

 Fig. 11-30 Crossed-Field Backward Wave Oscillator — Type-M Carcinotron. 



efficiency combined with wide-range electronic tuning makes these tubes 

 attractive for countermeasure or jamming applications. Backward wave 

 oscillators for high pulse powers have yet to be developed. 



11-7 THE PLATINOTRON 



The platinotron is a relatively new type of microwave power tube. It 

 bears a strong physical resemblance to the microwave magnetron and the 

 M-Carcinotron, but the differences in performance are very significant. 

 In its most interesting form, known as the ajyiplitron^ the tube functions as 

 a wideband amplifier and combines the magnetron virtues of high efficiency, 

 light weight, and low operating voltage with the ability to amplify signals 

 over a wide band of frequencies. 



The basic structure of the platinotron as compared with the magnetron 

 is shown in Fig. 11-31. The cathode structure is essentially the same in both 

 tubes. Both tubes are immersed in a magnetic field parallel to the axis of 

 the cathode, so that many of the comments that apply to the electron 

 trajectories in the magnetron are equally applicable to the platinotron. 

 The essential difference is in the anode structure. In the magnetron, the 

 slow wave structure, generally consisting of a series of cavity resonators, 

 is re-entrant or closed on itself, so that the RF circuitry forms a resonant 

 system with multiple modes of oscillation. In the platinotron, the slow 



