Two-Mode Waveguide for Equal Mode Velocities: Correction (Letters)

The T-septum waveguide was analyzed by Elliott using the orthonormal block method. The numerical results did not compare favorably with experimental measurements and it was suggested that the disparity was related primarily to the assumption of zero-thickness membranes for the septum. Later, Silvester analyzed the T-septum waveguide using a finite-element method and found very good agreement with the measured points, yet the septum thickness was again assumed to be infinitesimal. This letter is being written to dispel the implication that the orthonormal block method of analysis of the T-septum waveguide suffers for lack of accuracy. The universal curves as shown by Elliott will be presented here in corrected form along with experimental results further corroborating both Elliott´s and Silvester´s work.