Efficient hybrid MM/MoM technique for the CAD of circular combline filters with resonators of more general shape

Abstract

A hybrid mode-matching 0 I method-ofmoment (MOM) technique is presented for the efficient CAD and optimization of circular combline fflters involving more general elements like corrugated circular post and reentrant resonators. Using the free-space Green's function, the proposed technique combines the high flexibility of the MOM with the efficiency of the MM method. A locally refined adaptive tiangular surface mesh and the application of R a e Wilton-Glisson (RWG) basis functions achieve the reliable modeling of arbitrarily shaped structures. The building blocks are combined by the generalized scattering matrix (GSM) allowing typical MM elements like irises to be efficiently included. The attractive feature of the proposed method is its short computation time (order of a few seconds per frequency point) achieving the full-wave optimization of such fdters within reasonable times. The high versatility of the hybrid method is demonstrated at examples of practical interest; its efficiency and accuracy is verified by available measurements.

Application of a hybrid finite difference-mode matching method to the analysis of circular cavities loaded with cylindrical metallic objects

“…In this case, the more suitable are hybrid methods [12][13][14][15][16][17][18][19]. In these techniques the discrete approach like FDTD [12], method of moments (MoM) [13] or FEM [14,15], is only limited to the region where analytical solution of the problem is difficult.…”

“…In these techniques the discrete approach like FDTD [12], method of moments (MoM) [13] or FEM [14,15], is only limited to the region where analytical solution of the problem is difficult. Next, the discrete fields are combined with the analytical ones using general scattering matrix (GSM) [13][14][15]. This approach allows one to achieve higher flexibility, increase the accuracy of the method and reduce the numerical complexity of the analysis.…”

Analysis of Scattering From Arbitrary Configuration of Cylindrical Objects Using Hybrid Finite-Difference Mode-Matching Method

“…Since, in considered problems objects with arbitrary shape are assumed, the most powerful techniques of analysis are hybrid methods [13][14][15][16][17][18][19][20][21]. In these method the discrete techniques such as finite element method (FEM) [13][14][15], finite-difference time domain method (FDTD) [16][17][18] or frequency domain (FDFD) [19] methods and method of moments (MoM) [18,20,21] are used in limited region surrounding the analyzed structure.…”

“…In these method the discrete techniques such as finite element method (FEM) [13][14][15], finite-difference time domain method (FDTD) [16][17][18] or frequency domain (FDFD) [19] methods and method of moments (MoM) [18,20,21] are used in limited region surrounding the analyzed structure. In the outer region the fields are combined with analytical solution of the problem using e.g., integral equation technique [15,17] for open structures or general scattering matrix (GSM) approach for closed problems [13,20,21]. As a result, the hybrid techniques allows one to achieve higher flexibility, increase the accuracy and reduce the numerical complexity of the analysis.…”

“…In comparison to alternative methods [13][14][15][16][17][18][19][20][21] the presented approach allows one to analyze scattering from arbitrary set of cylindrical objects which can be located both in free space or in waveguide junctions. At first, in our approach each single object is considered separately in its local coordinate system.…”