The Analysis of a Coaxial-to-Waveguide Transition Using FDTD with Cylindrical to Rectangular Cell Interpolation Scheme

Abstract

We analyze the characteristics of a coaxial‐to‐waveguide transition based on the finite difference time domain (FDTD) method with the cylindrical to rectangular cell interpolation scheme. The scheme presented in this paper is well suited for the analysis of a microwave device with a probe near waveguide discontinuity because perfect TEM mode can be generated inside the coaxial cable by using the cylindrical cell. The scattering parameters of a designed Ka‐band transition are evaluated and compared with those of commercially available software, High Frequency Structure analysis Simulator (HFSS) and measured data. There exists good agreement between the measured and calculated data. In order to prove an accuracy of the interpolation scheme, a coaxial to waveguide transition with a disk‐loaded probe is analyzed by the present approach and the results of this analysis are compared with measured data. Comparison shows that our results match very closely to those of measurement and other approaches. The method presented in this paper can be applied to analyze the characteristics of a probe excited cavity, coaxial waveguide T‐Junctions, and so on.

Current compensation in probe feeding simulation using FDTD algorithm

“…However, in overlapping-grid region, it is also called interpolation region, rectangular and cylindrical coordinates are applied. We make a field transition between two coordinates using reciprocal interpolation technique [6]. The probe feeding structure is defined in cylindrical coordinate.…”

Calculation of a non-reflective connection in a coaxial line

“…Discontinuous changes in the cross section of the coaxial line are considered in [1,2]. The transitions between the coaxial line and the waveguide are also considered [3,4]. A change in the transverse dimensions of the lines to be connected is accompanied by a change in the structure of the electromagnetic field and the wave impedance of such lines.…”

“…When calculating a multi-step transition, it is impossible to apply the standard equivalent diagrams that are used to calculate transitions with a slight difference in the transverse dimensions of the connected lines. Here the method of computer electrodynamics [3] or the exact classical electrodynamics calculation [5] can be applied. 3).…”

Application of the method of integral equation for calculating a step-transition in a coaxial waveguide

“…A number of papers consider the propagation of electromagnetic waves in an inhomogeneous coaxial waveguide [1][2][3][4][5][6]. In [1], the analysis of inhomogeneities in a coaxial waveguide was carried out on the basis of telegraph equations.…”

“…The electrodynamic characteristics of simple inhomogeneities in multimode circular and coaxial waveguides are considered in the paper [4]. In [5][6], for the analysis of coaxial waveguides, the finite difference time domain method is used. This review shows that there is a need to consider this heterogeneity in a coaxial waveguide using classical electrodynamics methods [7][8].…”