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THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1951 



For comparison with equations (IV-21) and (IV-22), we shall next cal- 

 culate the attenuation of the parallel plate transmission line shown in Fig. 8. 



Fig. 8 — Plane parallel transmission line with solid conductors. 



For the fields we have again 



In shield: 



H. 



Ae 



v(y-d) 



In dielectric : 



(IV-23) 

 (IV-24) 

 (IV-25) 



(IV-26) 



(IV-27) 



(IV-28) 

 By matching the fields at j = dwG readily obtain the characteristic equation 



i^d) tanh i^d) + ^%^ = (IV-29) 



(T 



which gives approximately 



(^df = - — ' rjd (IV-30) 



We also determine the constant A to be unity. Proceeding as before, we find 

 for the propagation constant 



= \/(i)^Ho€i 



1 + 



1 



2d y/io)fio(Tj 



(IV-31) 



