TRANSMISSION PROPERTIES OF CLOGSTON TYPE CONDUCTORS 699 



coaxial cable, in that when one of the conductors carriers a current in 

 one direction, the other will carry a current in the opposite direction. 

 In Clogston II there is also a reversal of currents somewhere between the 

 outermost layers and the innermost. It is therefore a kind of a two 

 conductor cable, but the point of division between the conductors is 

 determined by the electromagnetic field configuration of the situation. 

 This point has been worked out by S. P. Morgan and will be referred to 

 in the second part of this paper. 



3. OPTIMUM PROPORTIONING 



The cross-sectional aspect of Clogston II is completely characterized 

 by that proportion of the diameter D which is occupied by the lamina- 

 tions. This proportion is called the Fill Factor and is defined by: 



011 = (D - d)/D Clogston II. (3) 



The fill factor is also a useful parameter for Clogston I, though it is 

 not sufficient to determine its geometry. It is defined by: 



0j = (Di - di-^ D2 - d2)/D2 Clogston I. (4) 



The additional parameters which, with the outer diameter D2, will 

 completely determine the geometry, are the ratio of the over-all thick- 

 ness of the inner laminated conductor to the over-all thickness of the 

 outer conductor, and a parameter which locates the inner diameter di 

 of the inner conductor. These parameters are defined by: 



T = (Di - dO/iD2 - d2), 



U = di/D2. 



In a conventional coaxial cable, shown in Fig. 3, the optimum value of 

 attenuation^ is obtained when D/d = 3.59. In Clogston cables no such 

 optimum values exist. 



S. P. Morgan, however, has shown that there are useful relative 

 optimum relations in Clogston I, which direct the choice of T and U 

 for the cables which are illustrated in this paper. For example, for a 

 fill factor of one-half, there is a broad optimum of attenuation when 

 T = 1.96 and U = 0.0842. Thus the over-all thickness of the inner 

 conductor is about twice that of the outer conductor, and the diameter 

 di of the inner core is about one-twelfth of the outer diameter D2 . With 



3 Green, E. I., F. A. Leibe and H. E. Curtis, The Proportioning of Shielded 

 Circuits for Minimum High-Frequency Attenuation, Bell System Tech. J., 15, 

 pp. 248-283, April, 1936. 



