Circular Electric Wave Transmission Through Serpentine Bends

Iii curved sections of round waveguide the TE 0 i - wave couples to the TM a and TEi,, waves, and power is converted to these waves when the TEoi wave is transmitted through bends. A form of bend which is inherently present even in an otherwise straight and perfect line is the serpentine bend, Fig. 1. Between discrete supports the pipe is deflected by the force of its own weight. The resulting curve is well known from the theory of elasticity. The curvature varies along the axis following essentially a square law. The minimum bending radius occurs at the supports. For the practical example of a copper pipe of 2§-inch O.D., 2.00inch I.D. and a supporting distance of 15 ft, this minimum bending radius is 992 ft. A uniform bend of this radius would convert most of the power incident in the TE 0 i wave to the TMn wave after a certain length of bend. Fortunately a serpentine bend with the same order of bending radius does not affect circular electric wave transmission as seriously as does a 1279