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• MATHEMATICAL SIMULATION AND CALCULATION OF SCATTERING CHARACTERISTICS IN FREQUENCY SELECTIVE PRINTED ANTENNA RADOME

  A.O. Kasyanov

  2021-02-13

  Abstract ▼

  Mathematical model of multilayered printed frequency selective surfaces with dielectric covers
  is presented in this paper. The model is built on the suggestion of array infinity and perfect
  conductivity of microstrip elements. Such printed structures can be used as frequency selective
  surface and as covers with controllable characteristics (for example tunable filters, adaptive radar
  cover, electronically switched polarizers). Full-wave analysis is executed by the integral equation
  method. The numerical solution of an integral equation has been obtained by Galerkin’s method.
  Unknown distribution of surface magnetic currents has been approximated by roof-top basic functions.
  The generalized scattering matrix method was used for simulation of multilayered printed
  frequency selective surface. The paper presents the compound algorithm which combines the integral
  equation method with the method of generalized scattering matrix. A lot of numerical examples
  are presented proving the algorithm effectiveness. By means of this model there were synthesized
  multilayer frequency selective surface as periodic arrays of the printed elements, which have
  arbitrary shape of reradiators. It is known, that the printed elements of special shape ensure, as
  rejecting and as transacting of electromagnetic waves in the given frequencies, and have neglected
  angular sensitivity. The results of constructive synthesis of printed frequency selective surfaces as
  rejecting or transmitting filters, which have neglected angular sensitivity, are represented in paper.
  Such an algorithm is rather flexible and multiple repeats the basic problem solution. It makes
  the procedure of computer code preparing much more effective and do not require to change the
  problem decision itself.

• TO ESTIMATION OF ATTRACTION AREA OF EQUILIBRIUM IN NONLINEAR CONTROL SYSTEMS

  Almashaal Mohammad Jalal

  6-14

  2025-07-31

  Abstract ▼

  Designing nonlinear control systems is still difficult, so many researchers are trying to find
  some useful ways and methods to solve this problem. As a result of such research, some methods
  have been seen trying to design a good enough control system for nonlinear plants. But a disadvantage
  of these methods is the complexity, so it created a need to compare some methods to determine
  which one is the easiest method to design a control system for nonlinear plants. It was
  found a way to compare two methods, which is comparing the regions of initial conditions of the systems which are designed using these methods. Two analytical nonlinear control systems design
  methods are compared on the example of the design control systems mobile robots. The algebraic
  polynomial-matrix method uses a quasilinear model, and the feedback linearization method uses
  particular feedback. Both considered methods give a bounded domain of equilibrium attraction,
  therefore the obtained control systems can be operated only with bounded initial conditions. The
  numerical example of designing the control systems for one object by these methods and the estimates
  of the attraction areas of the system’s equilibriums in these systems are given in the paper.
  As a result of this paper, it was found that using the algebraic polynomial-matrix method will get a
  bigger section of initial conditions of the plant’s variable than the same section which is given by
  the feedback linearization method.

• MATRIX METHOD FOR SIMULTANEOUS RELIABILITY ASSESSMENT OF COMPLEX MULTI-AGENT RECOFIGURABLE SYSTEMS

  V.K. Pshikhopov , А. L. Verevkin , А.R. Gaiduk , L.S. Verevkina

  249-259

  2026-09-10

  Abstract ▼

  The article presents the developed matrix method of simultaneous assessment of the reliability of several variants of complex multi-agent reconfigurable systems, as well as the staged method of reservation, which differ from the known ones in their simplicity and wide scope of application The matrix reliability assessment method consists in a matrix display of the reliability parameters of all agents of a specific variant of a group of system agents and a vector representation of the mission conditions. It is assumed that the mission reliability of a target group of agents is determined solely by the reliability of the agents themselves and the nature of their redundancy. The staged redundancy method is distinguished by its use of traditional standard redundancy schemes as stages in the process of redundant agent groups, significantly increasing the reliability of system variants. System agents are divided into active agents, directly performing the current mission, and passive agents, awaiting activation. Active agents, in turn, are divided into primary and backup agents. Primary agents initiate mission execution, while backup agents, awaiting replacement of failed active agents, can be in either an active state (hot standby) or a cold standby state. Specific mission conditions are taken into account by a vector of correction factors, significantly improving the accuracy of reliability assessment and agent group uptime prediction. An important feature of the proposed methods for assessing and predicting reliability is their analytical nature, which allows the use of modern high-speed computing tools in solving problems of ensuring the required reliability of missions performed by complex multi-agent systems

• RESULTS OF NUMERICAL STUDY OF SCATTERING CHARACTERISTICS IN ANTENNA RADOMES BASED ON METAL-DIELECTRIC GRATINGS

  А. О. Kasyanov

  2021-07-18

  Abstract ▼

  Mathematical model of multilayered printed frequency selective surfaces with dielectric covers
  is presented in this paper. The model is built on the suggestion of array infinity and perfect
  conductivity of microstrip elements. Such printed structures can be used as frequency selective
  surface and as covers with controllable characteristics (for example tunable filters, adaptive radar
  cover, electronically switched polarizers). Full-wave analysis is executed by the integral equation
  method of electromagnetics. The numerical solution of an integral equation has been obtained by
  Galerkin’s method. Unknown distribution of surface magnetic currents has been approximated by
  roof-top basic functions. The generalized scattering matrix method was used for simulation of
  multilayered printed frequency selective surface. The paper presents the compound algorithm
  which combines the integral equation method with the method of generalized scattering matrix. A
  lot of numerical examples are presented proving the algorithm effectiveness. By means of this
  model there were synthesized multilayer frequency selective surface as periodic arrays of the
  printed elements, which have arbitrary shape of reradiators. It is known, that the printed elements
  of special shape ensure, as rejecting and as transacting of electromagnetic waves in the given
  frequencies, and have neglected angular sensitivity. The results of constructive synthesis of printed
  frequency selective surfaces as rejecting or transmitting filters, which have neglected angular
  sensitivity, are represented in paper. Such an algorithm is rather flexible and multiple repeats the
  basic problem solution. It makes the procedure of computer code preparing much more effective
  and do not require to change the problem decision itself.