Кафедри
Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/35393
Переглянути
7 результатів
Результати пошуку
Документ Excitation of magnetoplasma oscillations in semiconductor structures by fluxes of charged particles(Національний технічний університет "Харківський політехнічний інститут", 2021) Serkov, Aleksandr; Breslavets, Vitaliy; Yakovenko, Igor; Fomenko, AndriiThe subject of the papers is the processes of analysis and physical model of excitation (amplification) of magnetoplasma oscillations (helicons) by fluxes of charged particles (electrons) in the presence of a constant magnetic field. This model is based on the Cherenkov mechanism for converting kinetic energy of particles into the energy of natural electromagnetic oscillations of solid-state (semiconductor) structures under resonance conditions when the particle velocities coincide with phase velocities of oscillations. The aim here is to justify the formulation of theoretical studies basing on the proposed physical model of generation (amplification) of electromagnetic oscillations (emergence of oscillation instabilities, i.e., exponential growth of their amplitude). We define parameters intervals for the external magnetic field, particle fluxes and types of semiconductor structures which this physical model is applied to. We perform theoretical study of the influence charged particle fluxes have on waveguide characteristics of semiconductor structures. The study justifies the possibility of generation and amplification of magnetoplasma oscillations in the submillimeter range. Our objectives are theoretical studies of the interaction of moving charges with electromagnetic oscillations of a semiconductor structure under conditions of Cherenkov radiation. The methods used are the method of successive approximations for solving the dispersion equations for a system of charged particle flux - semiconductor structure within the framework of hydrodynamic approach. The following results are obtained: Theoretical studies of the functioning of semiconductor components of electrical radio equipment in the presence of charged particle fluxes have been carried out. It is shown that the effect of the particle flux is characterized by the emergence of oscillation instabilities in the semiconductor structure. We have determined one of the mechanisms for the excitation of magnetoplasma oscillations based on the interaction of moving charges with the intrinsic fields of the structures that constitute a semiconductor unit. Such equipment failures occur under conditions of Cherenkov radiation. We have shown that this interaction leads to appearance of a mode of oscillation generation. The results of a comparative analysis of the data obtained in this work make it possible to use the proposed physical model to determine the criteria for the occurrence and development of instabilities of magnetoplasma oscillations. Conclusions. The results obtained in this work can be used in the development of active microwave range devices (amplifiers, generators and transducers of electromagnetic oscillations of the millimeter and submillimeter bands). The comparative analysis of quantitative estimates of the growth rates of oscillation instabilities, depending on the spatial configuration of the acting field (when induced current is parallel to the structure boundary), carried out in this work, provides a solution to the problem of optimizing the operating characteristics of active microwave devices.Документ Electromagnetic compatibility of semiconductor structures with a two-dimensional electron layer(Національний технічний університет "Харківський політехнічний інститут", 2019) Kravchenko, Volodymyr; Knyazev, Volodymyr; Serkov, Aleksandr; Breslavets, Vitaliy; Yakovenko, IgorThe subject matter is the mechanisms of interaction of the flow of charged particles with the surface plasmons of a two-dimensional electron layer (2D) due to the action of external pulsed electromagnetic radiation (EMP).The aim is obtaining design relations that determine to what degree the instabilities of natural vibrationsof a two-dimensional electronic layer of a semiconductor structure may influence the performance of semiconductor devices. The objectives area model of occurrence of reversible failures of radio products arising from the transformation of energy of currents induced by external pulsed radiation to excite electrostatic oscillations of a two-dimensional electronic layer of semiconductor structures. The methodsused areanalytical methods for solving electrodynamics (Maxwell) equations and material equations in the framework of kinetic approach. The following resultshave been obtained: The mechanisms of interaction of the flow of charged particles with the natural electromagnetic vibrations of a two-dimensional electron gas occurring due to the presence of a potential barrier at the interface have been studied. Investigations of functioning of semiconductor components of radio products (structures with two-dimensional electron gas) under the influence of strong pulsed electromagnetic fields have been carried out. A kinetic equation describing the change in thenumber of electromagnetic oscillations of such a system has been obtained. The solution of the equation has been found, which allows determining the influence of the barrier on the instability increment of surface vibrations as well as the contributions of the transmitted and reflected components of the particle flux to the increment. Equations for the increment of instabilitie sallow us to determine the energy loss of the induced currents on the excitation of natural oscillations i.e. the emergence of a mode of oscillation generation, which is characterized by a change in the volt-ampere characteristics of radio devices. Conclusion. A comparative analysis of the instabilities of vibrations of structures with a two-dimensional electron gas has been carried out under conditions when the interaction of waves and particles is randomand deterministic. It is shown that the differences in the expressions for increments are associated with a change in the size of the region of interaction of waves and particles. Differences in the influence of the potential barrier on the increment are established in cases where the interaction of surface plasmons and charged particles is determined or has the character of random collisions. The mechanisms of the influence of the boundary on the interaction of surface electromagnetic waves and electrons in the presence of a potential barrier are determined. I ntrinsic electromagnetic oscillations of a two-dimensional electron layer are taken as research objects. The results obtained in the work can be used to assess the operability of electronic equipment in millimeter and submillimeter ranges under the influence of pulsed electromagnetic fields.Документ Electromagnetic compatibility of semiconductor devices exposed to transitionradiation(Національний технічний університет "Харківський політехнічний інститут", 2019) Knyazev, Volodymyr; Serkov, Aleksandr; Breslavets, Vitaliy; Yakovenko, IgorThe subject of the paper is an analysis and a physical model of the occurrence of reversible failures in semiconductor diodes (when current-voltage characteristics of the devices are influenced by electromagnetic radiation (EMR)). The model is based on the mechanism with which the energy of currents induced by external EMR is converted into the energy of natural electromagnetic oscillations of solid-state components of radio units (transition radiationeffect).The aim of the paper is to justify experimental studies on the basis of the proposed physical model of reversible failures (occurrence of negative resistance sections in current-voltage curve of semiconductor diodes). We determined external electromagnetic radiation and semiconductor device parameter ranges with which this physical modelcan be applied. We conductedsome experiments to study the influence of pulsed electromagnetic radiation on the current-voltage characteristics of direct current diode sections. The experiments justified the presence of areas with negative differential resistance characteristic for the natural oscillation generation mode (an increase in forward current when the voltage drops).Our objectives are to perform experimental study of interactions betweenthe currents induced by external EMR and electrostatic oscillations of a semiconductor structure. Such interactionsresults from conversion of energy of moving charges (induced currents) into energy of electromagnetic oscillations under conditions of transition radiation when the particle flux goes along the normal to asemiconductor structure boundary. The methodsused areanalytical methods, i.e.solving Maxwell's equations and medium equations in the framework of the hydrodynamic approach. The followingresults wereobtained. Experimental studies of behavior of semiconductor components of electrical radio units exposed to strong pulsed electromagnetic fields have been carried out. The nature of changes in the performance of semiconductor components has been studied. It has been shown that the impactof pulsed electromagnetic radiation is accompanied by currents in the conductive elements of the units. We define here a certain type of reversible failures of semiconductor radio units. Failures of this type occur due to interaction between the external radiation inducedcurrents and own fields of radio equipment components. Such failures occurs in presence of transition radiation (when the current is directed along the normal to the boundary of the unit). Wearguethat suchinteractionslead to energy losses ininduced currents due to excitation of natural oscillations in the units, i.e. the units enters an oscillation generation mode, which is characterized by a change in the current-voltagecharacteristics of radio devices. With the results of comparative analysis of the experimental and calculated data obtained in this work,it is possible to use the proposed physical model of reversible failures and calculated derived relationships to determine criteria of occurrence and quantitative characteristics of reversible failures insemiconductor diodes exposed topulsed electromagnetic radiation (occurrence of S-shaped sections of direct current). Conclusion.The results obtained can be used to assess electromagnetic compatibility of active electronic devices (millimeter/submillimeter amplifiers, generators and transducers of electromagnetic oscillations) exposed toexternal pulsed electromagnetic fields. A comparative analysis of quantitative estimates of reversible failures of semiconductor devices depending on the spatial configuration of the affectingfield (the induced current is normal to the structure boundary) allows us to solve the problem of optimizing the degree of distortion inthe perating characteristics of these devices.Документ Excitation of surface vibrations of semiconductor structures exposedto external electromagnetic radiation(Національний технічний університет "Харківський політехнічний інститут", 2018) Serkov, A.; Breslavets, Vitaliy; Yakovenko, I.; Dziabenko, O.The subject of the study are processes of manifestation of instabilities of natural oscillations of semiconductor structures, which are caused by the mechanisms of interaction of charged particle flows in the presence of powerful external electromagnetic radiation. The goalis to obtain design relationships that allow determining the degree of deviation of the performance characteristics of semiconductor components from the norm, depending on the parameters of the external pulsed electromagnetic field. The taskis to construct a model of interaction induced by external electromagnetic radiation currents with electrostatic oscillations of the semiconductor structure. The modelis based on the realization of the resonance (Cherenkov) interaction of moving charges and electromagnetic oscillations under conditions where the phase velocity of the wave and the velocity of the charged particle are the same. The methodsused: analytical methods for solving the Maxwell equations and the equations of the medium in the framework of the hydrodynamic approach. The following results are obtained. Investigations of the functioning of semiconductor components of electronic equipment under the influence of strong-pulsed electromagnetic fields are carried out. The nature of changes in the working capacity of semiconductor components of the hardware component base is determined. It is shown that the influence of pulsed electromagnetic radiation is accompanied by the appearance of currents in the conductive elements of products and the appearance of intrinsic internal fields. One of the types of reversible failures of the semiconductor element base of electronic products is determined, based on the interaction of currents induced by external radiation with the intrinsic fields of the structures that complete the product. Similar failures are realized under conditions of Cherenkov radiation, when the current is parallel to the boundary of the structure. It is shown that this interaction leads to energy losses of the induced currents to excitation of the natural vibrations of the structure, i.e. the appearance of a mode of oscillation generation, which is characterized by a change in the volt-ampere characteristics of radio products. The comparative analysis of quantitative evaluations of reversible failures of semiconductor devices depending on the spatial configuration of the acting field, in which the induced current is paralleled to the structure boundary, allows solving problems of optimizing the degree of distortion of the performance characteristics of these devices. The results obtained in the work canbe used to evaluate the efficiency of active radioelectronic devices, for example, amplifiers, generators and converters of electromagnetic oscillations in the millimeter and submillimeter ranges under the influence of powerful external pulsed electromagnetic fields.Документ Method of coding information distributed by wireless communication lines under conditions of interference(Національний технічний університет "Харківський політехнічний інститут", 2018) Serkov, A.; Breslavets, Vitaliy; Tolkachov, M.; Kravets, V.The subject matter of the paper is the processes of analysis and evaluation of the effectiveness of information coding methods in wireless systems. The aim is to improve noise immunity of information messages under conditions of powerful electromagnetic interference, with the help of complex signal-code constructions. The objective is to develop a method for noise-immune encoding in a wireless information transmission system, providing increase ininformation transmission rate. The methods used: Simulation and digital signal coding. The following results have been obtained: A method for encoding information transmitted via wireless communication lines in presence of interference. For signal coding, it is proposed to use Gaussian monocycle with time-dependent position-pulse modulation (PPM). It is shown that for organization of independent channels within a single frequency band, it is practical to use a system of orthogonal codes. Pulses of the useful information signal accumulated in a receiver correlator provide significantly increase in signal-to-noise ratio, allowing transmission of information over a wide frequency range well below the noise level. As a result of encoding information in wireless information transmission systems with the help of ultra-short pulse signals, the effectiveness of the proposed method is aquantitatively and qualitatively evaluated. Using Pulse Position Modulation coding in wireless information transmission systems allows transmitting large volumes of information with high transmission rate and high noise immunity of the communication channel as well as protecting the channel from message interception. Ability to work with low radiating power and high signal capacity to penetrate various obstacles ensure fulfilment of electromagnetic compatibility requirements as well as stable communication in conditions of multipath radio wave propagation. Apossibility that powerful electromagnetic disturbances accompanying a lightning discharge may have catastrophic impact on the information transmission channel is also eliminated.Документ Noise-like signals in wireless information transmission systems(NTU "KhPI", 2017) Serkov, A.; Breslavets, Vitaliy; Tolkachov, M.; Churyumov, G.; Issam, SaadThe subject matteris analysis and evaluation of efficiency of noise-like signals in wireless information transmission systems. The aim is qualityof service improvement for mobile subscribers, due to communication channel multiplexing using complex signal-code structures. The objective is development of a systemic view of the technology of information transmission using ultra-short pulse signals focusing on main phenomena that arise at different stages of signal transmission in a wireless information transmission system. The methods use dare sequential analysis, simulation modeling and digital signal coding. The following results have been obtained. An antenna design featuring an expanding slit has been proposed for effective emission and receptionof noise-like signals. A method for controlling radiation pattern of such antenna array has been developed. Gaussian Monocycle coding of information with time position-pulse modulation has been justified to be used as a noise-like signal. It has been shown that for the organization of independent channels in one frequency band, it is practical touse a system of orthogonal codes, e.g. Walsh sequence. Due to accumulation of pulses of a useful information signal in the receiver correlator, significant increase insignal-to-noise ratio becomes possible, which enables information transmission over a wide frequency range well below the noise level. As a result, a systematic understanding of the technology of information transmission using ultra-short pulse signals in wireless information transmission systems is developed and a quantitative evaluation of the efficiency of the proposed technical solutionsis provided. Conclusion. The use of noise-like signals in wireless information transmission systems provides for high data transmission rates with high interference immunity and tapping protection communication channel. The ability to operate with low emitted power and the high penetrability of noise-like signals through various obstacles, for example, walls, allow meeting the requirements for electromagnetic compatibility and ensuring stable communication in conditions of multipath propagation of radio waves. These circum stances form the basis for the development and implementation of information transfer technology using noise-like signals when designingoffice networks.Документ Extraneous electromagnetic radiation impact on waveguide characteristics of a semiconductor superlattice(НТУ "ХПІ", 2018) Kravchenko, Volodymyr; Breslavets, Vitaliy; Yakovenko, Igor; Hui, Qiu JingThe subject matter is the mechanisms of emergence of instabilities in natural oscillations of semiconductor supertattices caused by their interaction with charged particle flows of extraneous electromagnetic radiation. The aimis calculating ratios to determine a degree of deviation of operating characteristics of semiconductor components from the norm, depending on the parameters of extraneous pulsed electromagnetic radiation. The objectiveis to model how currents that are induced with extraneous EMR interact with electrostatic oscillations of a semiconductor supertattice, using an implementation of (Cherenkov) resonance interaction of moving charges with electromagnetic oscillations under conditions where the phase velocity of the wave and the velocity of the charged particle are the same. The methods used: analytical methods for solving Maxwell's equations and medium equations in a framework of hydrodynamic approach. The following results are obtained. We have studied semiconductor components of electronic equipment (supertattices) being exposed to strong pulsed electromagnetic fields. The study was focused on the nature of changes in the working capacity of the components. We show that the effect of pulsed electromagnetic radiation is accompanied by an emergence of currents in the conductive hardware elements and an emergence of internal fields within them. One kind of reversible failures of semiconductor hardware elements is determined, based on interaction of extraneous radiation induced currents with the intrinsic fields of the supertattices of the hardware components. Similar failures occur under conditions of Cerenkov radiation (when the current is parallel to the structure boundary). It is shown that such interaction leads to energy losses in the induced currents spent to excitation of natural oscillations of the supertattice, i.e. to emergence of an oscillation generation mode that is characterized with a change in the volt-ampere characteristics of the hardware. The results obtained in this work can be used to evaluate the efficiency of active radio electronic devices (amplifiers, generators and converters of electromagnetic oscillations in the millimeter and sub-millimeter ranges) being exposed to extraneous pulsed electromagnetic fields. The comparative analysis of quantitative evaluations of reversible failures of semiconductor devices in dependence on the spatial configuration of the acting field (induced current parallel to the structure boundary) allows solving problems in optimizing the degree of distortion of the performance characteristics of these devices.