700 



BELL SYSTEM TECHNICAL JOURNAL 



Combining Eq. 31 and Eq. 39 and solving for V in terms of I 



2 



I' 



4 



(40) 



where t is the length of the cavity and \gQ is the resonant wavelength in the 

 line. 



CD 



10 



^ 9 



(0 6 

 a 7 



u. 6 

 o 



5 

 lij 



< 



°- 3 



U 

 10 

 3 

 <0 o 



3 4 5 6 7 8 9 10 20 30 40 50 60 60 100 



SELECTIVITY CLOADED Q) 



200 300 



Fig. 12— The relation between loaded Q and normalized susceptance. (Capacitive ob- 

 stacles) 



Thus, when this length, corresponding to the excess phase of the cavity 

 resonator, is absorbed in the length of Une connecting two cavities together, 

 the correct total connecting length becomes 



f. = (2w + 1) 



Xpo 



('.- a 



fl -\- h ^0 j_ ^ ^a 



-IT " 4 +'"T 



(41) 



where A and 4 are the lengths of the cavities and m is any integer including 

 zero. 



Obstacles in Waveguides 



The three properties of the cavity — the resonant frequency, the selectiv- 

 ity and the excess phase — are given in Equations 31, 32 and 39, regardless 

 of the sign of the normalized susceptance, B. In the case where the obstacles 

 are inductive, B is negative; and where the obstacles are capacitive, B is 

 positive. 



