LAMINATIOD TRANSMISSION LINES. I 



927 





J- — n r 1 7 •■ n r 



Aie + A 26 

 A'iA'2 sh nV = 



(15n - 4) _ (175n^ - 70n - 16) 

 "^ 30 4200 ^ + 



1 



(ir)/i + 4) ., (l7o7i- + 707i - 16) 



30 







4200 



0' + 



1 in 



(cjihY qVs 



0' + 



(188) 



(189) 



(190) 



By siibstitiitiiig the above series into equation (170), we can obtain 

 the variation of the stack impedance with frequency so long as /i/5i is 

 sufficiently small. Although in principle there would be no difficulty in 

 taking into account an arbitrary sheath impedance Z„(yo), for brevity 

 we shall restrict ourselves here to the case in which the sheath impedance 

 is so high that at all frequencies of interest the current in the sheath may 

 be neglected. Then we have equation (191) (see next page). 



< 



5^2 



2 5 12 5 



FREQUENCY f 



Fig. 7 — Surface resistance H of solid i)lates and laminated stacks versus 

 frequency/ on log-log scale. 



