The optimum spacing of bead supports in coaxial line at microwave frequencies

In coaxial transmission lines, the inner conductor is commonly supported by dielectric beads spaced at intervals along identical sections of line. At microwave frequencies, where the bead spacing is large compared with the wavelength, there result sharp peaks of reflection corresponding to reinforcement of the reflections of individual beads. Assuming that the reflections of the beads themselves have been reduced to a uniform minimum by careful design and production control, it is advantageous to disperse the beads in each section so as to reduce the cumulative reflection peaks. A dispersal has been found which is believed to yield the minimum value of peak reflection.