GUIDED-WAVE l'l{()PA(!ATI( )N' TIlKorciII CYKO.MAGXKTIC MKDIA (131 



1.0 

 0.9 

 0.8 

 0.7 

 0.6 

 0.5 

 0.4 

 0.3 

 0.2 



-I.O -0.8 -0.6 -0.4 -0.2 0.2 0.4 0.6 0.8 1.0 



(T 



Fig. 13 — Approximate course of modes in the /S^ — a plane for various -p values 

 and at two values of To . Fig. 13(a), above, /\i = 2.75, TEu-limit modes; — 1 < o- < 1. 

 Fig. 13(b), ro = 2.75, TEu-limit mode and incipient T]Mii-limit mode, o- > 1. Fig. 

 13(c), ro = 2.75, TEu-limit mode, a < -1. Fig. 13(d), (e) and (f), ro = 5.75, TEu- 

 limit and TEi2-limit modes; Fig. 13(d), -1 < o- < 1; Fig. 13(e), <r > 1; Fig. 13(f), 

 a < -1. Fig. 13(g), 13(h) and 13(i), ro = 5.75, TM„-limit modes; Fig. 13(g); 

 -1 < o- < 1; Fig. 13(h), (7 > 1; Fig. 13(i), <t < 1. It should be noted that a scale 



linear in 



1 + 



is used for convenience when \ a \ > crn 



continuously to a- = — cro , X2 = 



1 



(To 



and, simultaneously, the cut-off 



point of the TMu curve occupies the position relinquished by the for- 

 mer. The TMu mode now exists for all p. A new solution curve (TE12) 

 appears in the region bounded by 0/, (Oi)r and //, if p is not too large, 

 terminatuig at (Ia)t — I\, the point left by the TMi terminus. (If p 

 exceeds -y/l — ji^/uz' this curve will not exist at all.) 



Figs. 13(a) to (i) and 14 show the approximate course of the /3" — o- 

 curves for the TEn mode at ro = 2.75 and for the TEu , TMn and TEi2 

 modes at ro = 5.75. The incipient TMu mode at ro = 2.75 is shown 

 for positive 0-, p only. They were computed b}^ the methods outlined 

 above. 



4.14. Guides of large radius. It is of some interest because of the high 

 dielectric constant of ferrites to examine the behavior of the modes as 

 the radius, ro , is allowed to become very large. The two sides of the 

 G-equation will remain determinate for inilimited ro provided 



ro 



/[^IX-VI^J 



