A NEW MICROWAVE TRIODE 



533 



couples the input waveguide to the input cavity and is tuned by a small 

 trimming screw across its opening. The metal shell of the base of the 

 tube makes contact to the input cavity through spring-contact fingers 

 around its circumference and forms a part of the input cavity. The 

 cathode and its by-pass condenser, located within the envelope, complete 

 the input circuit cavity. The heater and cathode leads, brought out 

 through eyelets in the base of the tube, are isolated from the microwave 



Fig. 3. — Model eleven microwave circuit for the close-spaced triode looking into the 

 output waveguide. 



energy in the input cavity by means of the internal by-pass condenser. 

 When the tube is used as a modulator, this by-pass condenser acts as a 

 portion of the network through which the intermediate frequency signal 

 power is fed onto the cathode. 



The output circuit cavity is coupled to the output waveguide through a 

 coaxial transformer, a coaxial line and a wide-band coaxial-to-waveguide 

 transducer. The output cavity is bounded by the grid, the coaxial line 

 outer conductor, the radial face of the quarter-wave coaxial transformer 



