Frequency/time‐domain modelling of 3D waveguide structures by a BI‐RME approach

Abstract

SUMMARYThis paper presents a full wave method for the determination of the mathematical model of a 3D waveguide structure in the form of the pole expansion in the s-plane of its generalized admittance matrix. The method is based on a boundary integral-resonant mode expansion approach. By the introduction of appropriate state-variables, the method leads to the pole expansion by solving a linear generalized eigenvalue problem, like in the well-known techniques used up to now in frequency/time domain modelling based on "nite di!erence or "nite element methods. With respect to these methods we have the advantage of a signi"cant reduction in both memory allocation and computing time. Two examples show the accuracy of the results and the e$ciency of the method.

Design of compensated multiport waveguide junctions considering mechanization effects

“…Concretely, the 2-D BI-RME method [2] is used to characterize a rectangular waveguide with rounded corners. This multimodal technique has been combined with the 3-D BI-RME method [8], which yields a generalized admittance matrix of arbitrarily shaped 3-D cavities, to finally provide a wide-band electromagnetic characterization of the whole structure.…”

“…. , M ) represent the first M resonant wavenumbers of the shortcircuited cavity, and vectors y (i) are related to the eigenvectors associated to k i (see [8] for more details).…”

“…A more complex five-port device, specifically a compensated turnstile junction, considering these mechanization effects is also reported. It is important to emphasize that this work provides, for the first time to the authors' knowledge, a rigorous combination of 2-D and 3-D Boundary IntegralResonant Mode Expansion (BI-RME) techniques [2], [8] for the efficient analysis and design of compensated multiport waveguide junctions considering mechanization effects. To this respect, note that the novelty of this work lies on the fact that previous works of the authors did not considered the presence of rounded corners in the analyzed multiport junctions (i.e.…”

Full-Wave Analysis and Design of Broadband Turnstile Junctions

“…Afterwards, the 3-D Boundary Integral-Resonant Mode Expansion technique (BI-RME) [8] is employed to derive the generalized admittance matrix (GAM) of the rest of the structure, that is, a component with four rectangular waveguide ports and a coaxial access port (see Fig. 2).…”

“…The implemented modal technique, which is based on the 3-D Boundary Integral-Resonant Mode Expansion method [8], is very efficient from a computational point of view, thus minimizing the CPU effort related to the design process with respect to previous contributions. In addition to this, the diameter D of the circular waveguide of the designed turnstile junctions satisfies D ≤ a with the aim of reducing the number of excited higher order modes.…”