Propagation characteristics of a periodically loaded transmission line

A cable passing over periodic obstacles, such as existing in an aircraft's interior, can be modeled by a periodically loaded transmission line. This report calculates the propagation characteristics of a line loaded at regular intervals with identical, symmetrical T sections. The dispersion relation determining the possible modes of wave excitation on the line is derived, from which comprehensive information on the propagation constant, the passband-stopband structures, and the phase and group velocities is obtained. The results are illustrated numerically and graphically by working out a typical example.