262 



BELL SYSTEM TECHNICAL JOURNAL 



difficulties in using them. For these reasons stranded conductors do 

 not seem Hkely to find early application in broad band transmission 

 circuits. 



Optimum Proportioning as a Function of Conductor Resistance 



The optimum diameter ratio of a coaxial circuit may also be ex- 

 pressed broadly as a function of the two conductor resistances. As- 

 sume a coaxial circuit in which the high-frequency resistance of the 

 inner conductor varies, at least over a limited range, inversely as its 



0.1 0.2 0.3 0.4 0.5 1 2 3 4 5 



RATIO OF high-frequency RESISTANCES (INNER STRANDED CONDUCTOR TO 

 SOLID CONDUCTOR OF SAME SIZE BUT OF MATERIAL OF OUTER CONDUCTOR, ID-j 



Vn 

 Pig 6 — Optimum diameter ratio of coaxial circuit with stranded inner conductor. 



outer radius and that of the outer conductor as its inner radius, thus 



7? -*' 



R.='^ 



(27), (28) 



These relations are approximately true for all the types of circuits 

 which have been discussed. Let 



_ ki _ Ro c _ j?0 

 ' ^~h,~R,' h~Ri 



(29) 



