Re-expansion method for circular waveguide discontinuities: application to concentric expansion chambers

Area of Science:

• Electromagnetics and Wave Propagation
• Applied Physics

Background:

• Analyzing discontinuities in axi-symmetrical circular waveguides is crucial for understanding wave propagation.
• Existing methods may struggle with the complexity of velocity singularities at junction corners.

Purpose of the Study:

• To apply the re-expansion method for analyzing planar discontinuities in circular waveguides.
• To develop a computationally efficient technique for calculating waveguide parameters.

Main Methods:

• The re-expansion method is applied to expand normal modes at the junction plane.
• A system of functions is used to account for velocity singularities.
• The method is validated by analyzing concentric expansion chambers.

Main Results:

• The re-expansion method demonstrates high convergence, requiring few terms for practical solutions.
• Equivalent impedance and scattering matrices are derived, accounting for nonplanar waves and arbitrary mode coupling.
• An explicit formula for the transmission loss coefficient in expansion chambers is obtained.

Conclusions:

• The re-expansion method provides an accurate and efficient approach for analyzing waveguide discontinuities.
• This technique simplifies the calculation of electromagnetic parameters in complex waveguide structures.
• The findings are applicable to various practical problems involving circular waveguide junctions.