High Order FDFD computation of all waveguide modes using a single grid

Abstract

We describe here a High Order Finite Difference Frequency Domain approach to the cut-off frequency and mode computation in rectangular and circular waveguide with use of a single grid for both TE and TM modes. The proposed technique has been assested against a commercial FEM-based general-purpose EM solver

Design of a chemical reactor under microwave irradiation in resonance conditions

“…22is an eigenvalue problem, and could be solved numerically. Probably, the most effective approach is the finite-difference frequency-domain (FDFD) method [14], which can be applied both to scalar [15][16][17][18][19][20][21] and to vector [22,23] problems. As a matter of fact, the FDFD approach, namely the direct discretization of the differential eigenvalue problem, is the simplest numerical strategy to compute eigenvalues and modes of metallic hollow waveguides [23].…”

Ridge waveguide optimization with PSO algorithm

“…As a matter of fact, the FDFD approach, namely the direct discretization of the differential eigenvalue problem, is the simplest numerical strategy to compute eigenvalues and modes of metallic hollow WGs [18] and therefore it is well tailored to be used in PSO but it is useful also in procedure based on method of moments (MoM) [19,20] or mode matching (MM). [21] The WG section is discretized with a regular grid of sampling points, and the differential eigenvalue problem is replaced by a finite difference one, [22] using suitable Taylor approximations of second [6] or fourth [23] order. The standard FDFD approach, using two Cartesian sampling grids (one for TE modes and the other for TM ones, due to the different boundary conditions), allows a very effective solution for rectangular WGs or, more generally, for WG with piecewise rectangular boundaries, since in these cases the boundary is perfectly fitted to the discretization grid, either uniform or non-uniform.…”

Optimization of rectangular ridge waveguides using PSO

“…where φ is the Hertz-Debye (HD) potential , is replaced by a finite difference one, using suitable Taylor approximations of second [5] or fourth [12] order. These approximations must, of course, include the different boundary conditions for TE and TM modes [1].…”