Anatoly Kirilenko

Automatic electromagnetic solvers based on mode-matching, transverse resonance, and S-matrix techniques

The main goal of the paper is to present a new generalized mode-matching (GMM) approach to both mode bases and S-matrices calculation of complicated waveguide circuits. Development of the GMM procedures makes it possible to realize totally automatic algorithms for a wide set of configurations avoiding a specialized analytical treatment of each new boundary-value problem. Moreover, the background for linking up the interface tools of a circuit geometry specification and editing is provided by the GMM approach together with the special algorithms for recognizing the object configurations and for data preparation. The class of objects that can be calculated by the suggested approach includes any WG circuits with metal boundaries specified in the Cartesian coordinate system or with the smooth boundaries that may be replaced by a staircase surface. The corresponding electromagnetic solvers are closer to the software based on the mesh methods in generality, in the same time saving the high accuracy and computation speed typical for highly specialized mode-matching procedures.

Waveguide diplexer and multiplexer design

A new computer-aided procedure of designing waveguide manifold multiplexers, which combines a rigorous numerical analysis of electromagnetic characteristics of the key elements of the structure and a simple circuit engineering design technique, is proposed. This procedure enables one to obtain the required multiplexer characteristics without any experimental corrections at the minimum computer time expense. Typical design results are given to demonstrate the efficiency of the method. >

Evanescent-mode ridged waveguide bandpass filters with improved performance

New types of evanescent-mode bandpass filters based on the ridged waveguide sections are considered. Insertion of additional inductive strips between the ridge sections enables one to reduce the longitudinal filter size, increase the cross section of the ridged waveguide housing, and achieve a sufficient improvement of stopband characteristics. Results of designing the millimeter-wave filters and comparison with the measured data are presented.

Spectral approach to the synthesis of bandstop filters

A nontraditional approach to the synthesis of bandstop filters (BSF) based on the analysis of the spectrum of complex eigenfrequencies of multimode resonators forming a filter is described. Two types of BSF resonators, which are formed by cross-section enlargements of a finite length of a rectangular waveguide in E- or H-plane, are considered. It was shown that a BSF of the first type had no spurious stopbands and practically did not introduce a loss in the passband. The high accuracy of the filter design is confirmed by the experimental data. >

Spatial filter with quasi-elliptical response

Spatial filters with quasi-elliptical responses are presented. Proposed designs are based on using the frequency-selective surface with at least two different apertures over the period. Such a surface provides the frequency response with a transmission zero. Just cutting additional aperture over the surface period makes possible such non-trivial feature. Two approaches to design a bandpass filter with quasi elliptical response are presented. In the first case a multiaperture surface is used as a high-quality resonant section, providing the response with the point of the total transmission and with two rejection resonances. In the second case, the grating of perforated strips, is used as a coupling element between half-lambda spatial resonators of an extracted-pole directly coupled filter.

Harmonic rejection filters for the dominant and the higher waveguide modes based on the slotted strips

The simplest notch-type filters to reject the dominant and higher modes in the multimode frequency band are proposed using resonant properties of the iris formed by slotted capacitive strips. Various configurations of the slotted strip iris are considered. The simplest one is a centered capacitive strip in a rectangular waveguide with centered single slot that is able to reject the dominant mode up to the TE30-cutoff. The second one is the double-slot capacitive iris that has the ability to reject at the same frequency both the dominant mode and the TE20-mode. The third configuration is based on two double-slot capacitive strips placed close to the upper and lower walls of the waveguide and provides rejection of the TE10, TE20 and TM11-modes simultaneously. Configurations based on slotted inductive strips to reject TE01 and TM11 modes are also considered. These notch filters are perfectly matched in the operating single-mode range, can be easily fabricated and implemented.

Semi‐inversion method for an accurate analysis of rectangular waveguide H plane angular discontinuities

The new efficient numerical-analytical method of electromagnetic interior boundary value problem solving is presented with waveguide H plane angled bends as examples of implementation. The method essence consists in the analytical inversion of the main difference part of the initially derived ill-posed matrix equation of the first kind. As a result, the problem is reduced to the solution of the second-kind matrix equation with an invertible operator. The proposed method differs from other methods dealing with so-called modified Wiener-Hopf geometry structures. It is oriented to noncoordinate boundary value problems to which the ones of angular waveguide discontinuities are related. Detailed consideration of all parts of the numerical algorithm ensures its high efficiency. As application examples, the data for designing the matched truncated corners in a single-mode waveguide and the results of comparison of the known high-frequency heuristic estimations with the exact simulation of waveguide corners having a quasi-optical mirror are presented.

THE MODE-MATCHING TECHNIQUE AND FAST NUMERICAL MODELS OF ARBITRARY COORDINATE WAVEGUIDE OBJECTS

A new algorithm based on two versions of mode-matching (MMT) approaches is proposed for solving the boundary value problems associated with arbitrary waveguides or cavities having piece-wise coordinate surfaces. The solutions are initially based on a pre-processing procedure aimed for automatic recognition of an objects structure and forming the matrix operators taking part in the mode bases search, or in the calculation of step junction S-matrixes. The new code has been tested by the relatively simple objects considered earlier, and by new objects that were not previously considered for MMT modelling because of the laboriousness of an algorithm elaboration. It was shown that the new MMT electromagnetic solver was also applicable in the cases of smooth boundary objects at step-wise approximated surfaces.

Electromagnetic modeling of multi-layer microwave circuits by the longitudinal decomposition approach

A system approach based on the transverse-resonance technique and well-equipped modeling system is used to calculate the eigen-mode spectrum of multiconductor lines with piece-wise continuous coordinate boundaries of their cross-section. The exact models of the multi-layer circuits are built with the mode-matching and generalized S-matrix techniques. Viability of the created program tools is demonstrated with the examples of a multi-turn loop inductor and a third-order low-pass filter.

Radiation of TEM-wave from plane-parallel waveguide with corrugated flange

The mathematical model of radiation of the H-polarized wave from a plane-parallel waveguide with a corrugated flange is constructed. Grooves of arbitrary sizes are symmetrically cut of on perfectly conductive screens to the left and to the right of the waveguide. The investigated structure can be considered as the two-dimensional model of the surface-wave antenna, which consists of the guide in the form of a lamellar grating with finite number of grooves and the exciter in the form of a plane-parallel waveguide.