SOME RESULTS ON CYLINDRICAL CAVITY RESONATORS 



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frequency of that particular mode are undisturbed. For example, Fig. 13 

 shows the £-lines in a TE llw mode in a circular cylinder. If the upper 

 half of the cylinder wall is replaced by a new surface, shown dotted, the 

 field and frequency in the resulting flattened cylinder will be the same as 



NEW SURFACE PERPENDICULAR 

 TO E- LINES LEAVES REST OF 

 FIELD AND FREQUENCY UNALTERED 



Fig. 13 — E Lines in TE lire mode 



^ORIGINAL CYLINDER 



t'- 



Fig. 14— "TE 01m" mode in half-cylinder 



before. Indeed, they will also be the same in the crescent-shaped resonator 

 indicated in the figure. 



Except for isolated cases, all the other modes of the original cylinder will 

 be perturbed in frequency since the old fields fail to satisfy the boundary 

 conditions over the new surface. Furthermore, if the original cylinder was 



