TRANSMISSION PROPERTIES OF CLOGSTON TYPE CONDUCTORS 697 



speed of propagation is constant over the entire cross-section. A coaxial 

 cable having an inner laminated conductor and an outer laminated sheath 

 must obey the following relation to obtain the desired effect: 



=«■('+ 7) • 



/Z/€z = ;xe 1 + - , (2) 



where: 



Hi = Permeability in space between inner and outer conductor. 



jLt = Permeability of laminated conductors. 



€1 = Dielectric constant of insulation between inner and outer con- 

 ductor. 



€ = Dielectric constant of insulating layers in the laminated con- 

 ductors. 



w = Thickness of copper layers. 



t = Thickness of insulating layers. 



In (2) the expression €(1 + w/t) is of course the mean dielectric con- 

 stant of the laminated conductor. Since I/Vmi^i is the speed of propaga- 

 tion in the main dielectric, equation (2) indicates that the speed of 

 propagation is the same over the entire cross section of the cable. Equa- 

 tion (2) must be satisfied to a high degree of accuracy, otherwise deep 

 penetration is not possible. 



2. DEFINITION OF CLOGSTON CABLES 



Two laminated conductors arranged as a coaxial cable are shown 

 in Fig. 1. The inner conductor consists of a solid copper wire of diameter 

 di, over which a large number of alternate layers of insulation and 

 copper are arranged as concentric thin tubes. The over-all diameter of 

 the inner conductor is Di. The outer conductor of the coaxial cable con- 

 sists of a laminated tube of inner diameter d2 and outer diameter D2. 

 The space between D2 and 6^2 is filled with thin concentric tubes of 

 copper and insulation of the same thicknesses as for the inner conductor. 

 The outside of the outer conductor is covered with a sohd copper sheath 

 for protection, shielding and energizing purposes. This type of cable 

 has been named Clogston I. 



By adding more layers to the outside of the inner conductor and 

 more layers to the inside of the outer conductor, the space between 

 them is completely filled when ^2 = Di. Such a cable is shown in Fig. 2, 

 and has been named Clogston II. 



Clogston I may be thought of as a physical variant of the conventional 



