Electrodynamic Characteristics of T-Mode Coaxial Waveguides with Elliptical Cross-Section

Abstract

The paper presents a rigorous solution of the electrodynamic problem for T-type waves in a coaxial waveguide of elliptical cross-section. The solution was obtained using the original modified elliptical coordinate system. The advantages of this approach are convenient expressions for the electrodynamic characteristics of the transmission line and a simple transition to a particular case of a circular waveguide. The authors have obtained explicit expressions for the impedance, transmitted power and propagation losses of the coaxial elliptical waveguide with T-type waves, and have analyzed their dependences on the size and shape of the cross-section of the transmission line. The graphs of the dependences of these characteristics on the normalized parameters that define the shape and size of the waveguide allow choosing the geometric dimensions of the transmission line based on the requirements of a given characteristic impedance, limiting transmitted power or losses. It is shown that at large eccentricities, the energy in waveguides with similar sizes of internal and external conductors and low wave resistance is concentrated near the foci, which allows using such waveguides as the basis for developing effective probes for radio-spectroscopic studies.