1194 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1954 



the TM modes. In Part I where the propagation in guides of very large 

 radius was briefly examined, it may be recalled that in both of the ranges 

 < cr < ao and a < —1 the field patterns approached those of a plane 

 wave rotating in the same sense as the pattern as a whole. Again, it was 

 found that for — cro < o- < or o- > 1, the field at most points in the 

 guide was locally rotating in the opposite direction to that of the whole 

 pattern. The points of similarity to the present case are clear and it is 

 also evident that the TE mode more nearly approaches the large guide 

 situation because r^ = 5.75 is much further above the cut-off radius for 

 this mode than it is beyond the cut-off for the TM-mode. 



ACKNOWLEDGMENTS 



We are indebted to M. T. Weiss for frequent consultations and for 

 permission to use some of the data computed for him. We are also 

 obliged to J. H. Rowen and to S. P. Morgan, Jr., for advice in some 

 matters relating to Part III, and to R. Kompfner for useful discussions 

 concerning the "non-reciprocal helix." R. W. Hamming arranged the 

 integration of the Ricatti equation of Part II. 



Special thanks are due to Mrs. A. Rebarber for the many computa- 

 tions relating to Parts I and III, to Mrs. C. A. Lambert for her calcu- 

 lations on Part II, and to Miss M. J. Brannon for a number of results 

 computed for Part III. 



REFERENCES 



1. A. A. Th. M. Van Trier, Applied Sci. Res., Sec. B, 3, p. 305, B. Lax, Private 



communication. 



2. R. B. Adler, Res. Lab. of Electronics, M. I. T., Teclmical Report No. 102, May, 



1949. 



3. J. H. Rowen, B. S. T. J., 32, pp. 1333-1369, Nov., 1953. 



