D. Yu. Kulik

Fast full 3D EM CAD of waveguide units based on the generalized mode matching technique

A unique 3D EM solver based on the generalized mode matching technique (MMT) and aimed to solve the problems of analysis and synthesis of a wide class of passive devices is presented. The high efficiency of the CAD software will be demonstrated at some typical examples.

Compact polarization plane rotator by an arbitrary angle

We have studied the possibility to design a compact polarization plane rotator of electromagnetic waves based on the structures with dihedral symmetry. Proposed structure allows rotation of polarization plane at arbitrary angles and has acceptable loss in given frequency band.

Calculation of tem-modes in the waveguides having orthogon cross-section

A general analysis for the modal characterization of multiply connected, hollow, conducting waveguides is presented. It is relevant to waveguides with an orthogon cross-section. The transverse electromagnetic (TEM)-modes are analyzed. The approach described allows getting the exact and high-speed algorithm which lends itself naturally to parallelization.

Integrated software package for synthesis, analysis and optimization of frequency-selective devices of millimeter and centimeter waves

The state of the art of theory and practice of signal frequency selection in the millimeter and centimeter wave ranges can be described from one hand as going to more sophisticated schemes of filter building and from another hand, especially in millimeter waves, by extensive usage of practically non-tuning configurations. The first direction as well as the second one is based on the powerful software and on modern production processes, that provide minimal tolerances. Below is a summary of the results that have been obtained in IRE NASU regarding to one of this two sides of filter problems: the short description of the set of software packages for the synthesis and analysis of low-pass (LPF), wide-band and narrow-band band-pass (BPF), and band-stop (BSF) rejection waveguide filters.

Compact polarization plane rotator for arbitrary angle

We have studied the possibility to design a compact polarization plane rotator of electromagnetic waves based on the structures with dihedral symmetry. Proposed structure allows rotation of polarization plane at arbitrary angles and has acceptable loss in given frequency band.

Recent advances in computational electromagnetics for microwaves in IRE NASU

Recent advances in problem-oriented and general-purpose microwave-oriented software and applications developed in the department of computational electromagnetics are considered. Numerical-analytical automatic mode-matching based models are extended on the objects given in cylindrical coordinate system. The geometry has to be specified as the set of piece-wise coordinate fragments in Cartesian (MWD1 or MWD2 with account of edge behavior) or in Cartesian or cylindrical coordinates (MWD3) with automatic cross-section geometry recognition and subsequent formation of corresponding mode-matching technique and S-matrix based numerical algorithms. The future extension to the double-periodical screens and multilayer printed circuits (MWD4) is described moving to terahertz frequency band and “metamaterial” investigations. A set of new microwave devices is proposed which are based on the nonstandard physical principles such as the fringing field interaction, new types of eigen-oscillations of 3D open objects and artificial “optical activity”. They are the band-stop and band-pass waveguide filters, antenna-feed units, polarization rotators, twists etc.

Rotation of the polarization plane by double-layer planar-chiral structures. Review of the results of theoretical and experimental studies

This article provides examples that illustrate the search for different two-layer metamaterials that provide rotation of the polarization plane (“optical activity”). Selected objects show a twenty-year history of the search for a new principle of creation of polarization rotators based on planar metamaterials that were implemented in the form of thin-layered periodic structures. The manifestation of optical activity, presence or absence of satisfactory or perfect matching, the possibility of a multiband phenomena, the role of high spatial harmonics in “electromagnetics” of this effect are explained by the features of the eigen-oscillations that are excited in the gap of the multilayer structure.

Compact polarization rotators based on the diaphragms with several rectangular apertures

A possibility to design a compact polarization rotator based on the structures of dihedral symmetry is studied. Here, the diaphragms with several equal rectangular apertures are considered as dihedral symmetry structures. Ultimate performances of the rotators considered are obtained by using different optimization procedures. They demonstrate acceptable reflection in the predetermined frequency band The rotators that achieve the polarization plane rotation by an angle of choice are examined as well.

Transversal partial-height inserts in a rectangular waveguide as building blocks for multi-band filters

Rectangular waveguide section with two partial-height transversal inserts located side by side is examined. Such a section acts as a resonator providing two transmission zeros and one transmission resonance located between these zeros simultaneously. Thus, the number of transmission zeros is twice more than the number of waveguide sections. The broadband quarter-wavelength resonator filter using such sections provides two stopbands and one passband simultaneously. Their bandwidths and locations are controlled both by the section geometry and the distance between the sections. Two closely spaced sections providing two independent stopbands are proposed as a perspective block for a filter with complicated frequency response.

The shipborne radar antenna pattern at over-horizon object observation

The paper considers the possibilities for shipborne radar (/spl lambda/ = 4.5 cm) to detect over-the-horizon objects in higher refraction conditions. It is shown that, due to antenna pattern adaptation to high refraction coefficient gradients in the troposphere lower layers, the radar receiver output signal-to-noise ratio can increase by 20-23 dB.