A COUPLED RESONATOR REFLEX KLYSTRON 749 



Operation in the 4000-mc band was found to require a closely fitting 

 primary cavity resonating in its principal mode. This unit, made of 

 gold plated brass, is coupled to the output waveguide and secondary 

 cavity respectively through two rectangular irises the sizes of which are 

 independently variable by means of shutters. Toroidal contact springs 

 located in circular grooves grip the inserted tube and complete the 

 external circuit. The secondary cavity consists of a length of rectangular 

 waveguide and uses a movable contacting plunger for tuning. A micro- 

 meter driven resistance vane may be inserted into this cavity through a 

 longitudinal slot in its top surface thereby obtaining a wide range of 

 continuously variable Q's. The entire unit is attached to the output 

 waveguide by means of the adapter plate shown to the right of the 

 primary cavity in Fig. 14. 



A coupled resonator circuit having a tunable primary cavity is shown 

 in the photograph of Fig. 15. The secondary cavity of this unit is identical 

 to the one shown in the Fig. 14 but the primary resonator has been 



SECONDARY Q 

 ADJUSTMENT 



6 BL 6 



TUNING 

 PLUNGER 



SECONDARY 

 CAVITY 



TUNING 

 ADJUSTMENT 



Fig. 15 — An experimental coupled resonator reflex klystron with a tunable 

 primary cavity. The mechanical tuning range of this tube extends from 3700-4200 



