Observed 5-6 mm Attenuation for the Circular Electric Wave in Small and Medium-Sized Pipes

Sincc 5.4-mm dominant-mode rectangular waveguide has attenuations of the order of 60 db/100 ft, another transmission technique is required in applications which involve appreciable line lengths. Losses may be reduced by the use of oversize waveguide; some earlier work with dominant mode transmission in slightly oversize round waveguide (two or three propagating modes) has been reported.1 The possibility of still lower losses exists with circular electric wave transmission in an oversize round waveguide. Miller and Beck2 have computed the theoretical relative transmission losses of the TE 0 i and TEn modes as functions of 1 A. P. King, Dominant Wave Transmission Characteristics of a Multimode Round Waveguide, Proc. I.R.E., 40, pp 966-969, Aug., 1952. 2 S. E. Miller and A. C. Beck, Low Loss Waveguide Transmission, Proc. I.R.E., 41, pp 348-358, March, 1953.