Over-moded rectangular waveguide for high-power transmission

The limitation in power-carrying capacity of standard-size rectangular waveguides due to Joule heating effects is briefly discussed. Suggestions are advanced for using a larger-sized rectangular waveguide whose transverse dimensions are just less than ¿ × 2¿. The problems that arise from over-moding are considered, with particular reference to trapped-mode resonance effects. A method of eliminating these resonances using a multiple-slot filter suitable for high power levels is suggested. Experimental results on such a system at low power levels are described.