VOUR-FOLE ADMITTANCES OT MICROWAVE TRIODES 655 



grid, 1553 triode having input and output spacings of 0.5 and 12 mils respec- 

 tively. The capacitances averaged about 0.008 /x/xf, which would correspond 

 to a value of Vi2 of 0.0002 mho at 4060 megacycles. The latter is about 50 

 times lower than the measured 4060 megacycle value. Evidently, therefore, 

 electromagnetic coupling plays a dominant role. 



Reciprocity should give a reasonable idea of the accuracy of these meas- 

 urements. Thus, for Si = 0.001" and ^2 = 0.012'', one would expect the 

 same yn as for the case where Si = 0.012" and S2 = 0.001". An examination 

 of the data will indicate that the reciprocal differences are of the order of 

 10% in some cases. These differences may be partly the result of the change 

 in line cross section encountered in going from the input to the output. 

 That is to say, the two cases bemg compared are not quite reciprocal in 

 geometr)'. 



Figure 8 shows the phase of yn for the parallel wire grid. Because of the 

 low transmission through the grids there was not sufficient energy to deter- 

 mine the transfer phases with any very great accuracy, particularly for 

 wide spacings in the case of the parallel wire grid and for all spacings in 

 the case of the cross-lateral. Consequently, Fig. 8 shows only those results 

 which are believed to be reasonably accurate. 



The author wishes to acknowledge the contribution of Mr. F. A. Braun 

 who ably assisted in this work. 



