Mode conv., Resonant Absorption in Bent Overmoded Waveguide Abstract
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ALMA Memo # 550
Mode conversion and Resonant Absorption in Bent Overmoded Waveguide
A.-L. Fontana and B. Lazareff
2006-06-05
Mode conversion losses are a concern when an oversize waveguide is used to minimize ohmic losses. We present computations of mode conversion in oversize rectangular waveguide bends.
The numerical results are based on a published analytical formulation of the problem. They are presented in a dimensionless form applicable to a range of parameters believed to cover practical cases of interest for engineers that need to design a signal transport involving oversized waveguide and bends.
A few cases have been cross validated using a 3D EM simulation software; the numerical and analytical results are in good agreement.
Oversized waveguide bends are sometimes used to minize ohmic losses when a signal must be transported over a significant distance. The waveguide devices at both ends are usually in a smaller, single-mode waveguide size, and are connected to the overmode waveguide by suitable transitions. The combination forms a resonant cavity for higher order modes. We examine how the transmission of the fundamental mode is affected by resonances in the higher order modes.
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