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2025-04-09

Robust Mode Matching of Waveguide Discontinuities by Minimizing Mean-Squared Error

James R. Nagel,

Dr. James R. Nagel

L3Harris

United States

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Karl Warnick

Dr. Karl Warnick

Department of Electrical and Computer Engineering

Brigham Young University

USA

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Progress In Electromagnetics Research C, Vol. 154, 175-182, 2025

doi:10.2528/PIERC25012101

Abstract

The Mode-Matching Method (MMM) is a numerical technique that can be used to calculate electromagnetic wave propagation through a stepped waveguide junction. We present a generalized approach to mode-matching that works by minimizing the mean-squared error (MSE) of electromagnetic boundary conditions. The process begins by expressing each component of the electromagnetic field profile as a finite summation of modes within each waveguide region. Given some arbitrary pair of mode profiles, we next calculate the squared-error of each boundary condition along the entire span of the junction. The squared error is then averaged across the junction, resulting in a single matrix-vector equation for MSE. That equation is finally differentiated with respect to the mode amplitudes, and the result is then set to zero. The solution is thus a field profile in each waveguide region that minimizes the MSE of electromagnetic boundary conditions.

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James R. Nagel, and Karl Warnick, "Robust Mode Matching of Waveguide Discontinuities by Minimizing Mean-Squared Error," Progress In Electromagnetics Research C, Vol. 154, 175-182, 2025.
doi:10.2528/PIERC25012101

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