Funtov Alexandr

@sgu.ru

кафедра электроники, колебаний и волн
Федеральное государственное бюджетное образовательное учреждение высшего образования «Саратовский национальный исследовательский государственный университет имени Н.Г. Чернышевского»



           

https://researchid.co/funtovalexandr
6

Scopus Publications

Scopus Publications

  • About theory of hybride TWTO and an amplifire with a complex permittivity
    and Aleksandr Funtov
    Saratov State University
    The purpose of this work is to construct a nonlinear theory of a hybrid between travelling wave tube (TWT) and an amplifier with a complex permittivity. Methods. The following model is considered: an ion-compensated one-dimensional electron beam penetrates the input travelling wave tube section, then flies into a medium with a complex permittivity, and then enters the output travelling wave tube section. A linear theory of this hybrid is constructed, and its results are compared with the results of the well-known linear theory of travelling wave tube. A nonlinear theory of this hybrid was constructed by a modified wave method, and the results were compared with the nonlinear travelling wave tube theory obtained by the classical Ovcharov–Solntsev’s wave method. In addition, to test the limits of applicability of the obtained results, a stationary nonlinear theory of the hybrid was constructed, obtained using the large particle method. The results of this theory were also compared with the stationary nonlinear travelling wave tube theory constructed using the large particle method. Results and conclusion. Based on the results of the developed theories, it is shown that, under certain parameters, the linear theory and nonlinear theories (both by the modified Ovcharov–Solntsev’s wave method and by the large particle method) make it possible to obtain comparable results both in the case of a classical travelling wave tube and for the hybrid under study. It is shown that under certain parameters, due to the resistive instability, the bunching of electrons can be noticeably improved and, as a result, the gain of the hybrid can exceed the gain in a classical travelling wave tube with the same parameters and the same total length of the device in the linear mode of operation. In the nonlinear mode of operation, the specified hybrid, with optimal environmental parameters, can have significantly higher values of output power and efficiency than travelling wave tube with the same value of the space charge parameter and the Pierce parameter.

  • About theory of extended interaction klystron and drift space in the form of medium with complex permittivity
    and Aleksandr Funtov
    Saratov State University
    Purpose of this work is to construct a theory of extended interaction klystron with ordinary distributed resonators, but with a drift space in the form of medium with complex permittivity. Methods. For this, a hybrid of extended interaction klystron and an amplifier with a complex permittivity is considered in the framework of the weak signal approximation. Two types of configurations of a extended interaction klystron were considered: with two and three distributed resonators. For a two-resonator klystron with distributed interaction, two cases are considered: without reflections from the ends of distributed resonators and the case when the input binder is fully matched to the external transmission line, and for the second distributed resonator, the so-called condition of critical coupling of the “hot” resonator with the transmission line is satisfied. For a three-resonator klystron with distributed interaction, the case is considered without reflections from the ends of distributed resonators. Results and conclusion. According to the results of the developed theory of a weak signal in a extended interaction klystron with ordinary distributed resonators and a drift space with a complex dielectric constant, by choosing the parameters, it is possible to achieve a greater gain at a length that is shorter than in a conventional extended interaction klystron, all other things being equal. In addition, the presence of an intermediate distributed resonator makes it possible to increase the gain while maintaining the full length of the device.




  • Linear Theory of M-Type Amplifier on Absorption (Amplification and Noise)
    A.A. Funtov
    IEEE
    A linear theory of the interaction of an electron beam with fields of media with complex conductivity in crossed static electric and magnetic fields is presented. The flux flies between two flat surfaces, generally having complex conductivity. The models of an infinite thin beam and a beam of finite thickness are investigated. The noise coefficient for a lamp on an M-type absorption with a beam of finite thickness is estimated.

  • Noise in resistive-wall amplifier of m-type with «thick» beam
    and A. A. Funtov
    Saratov State University
    Цель нашего исследования – изучение шумов в резистивном усилителе со скрещенными электрическим и магнитным полями с пучком конечной толщины. Если теория резистивного усилителя О-типа достаточно известна, хотя бы как классический пример прибора, использующего волны с отрицательной энергией, то резистивный усилитель М-типа, в котором тоже используются волны с отрицательной энергией, до недавнего времени почти не исследовался. Представляется интересным изучить шумы в приборе со скрещенными полями, тем более, что в ранних работах упоминалось о возможном малом уровне шума. Метод. Шумы изучаются на основе ранее построенной двумерной линейной адиабатической теории устройства с электронным потоком конечной толщины, который движется в скрещенных статических электрическом и магнитном полях (поток магнетронного типа) между двумя плоскими поверхностями с комплексной проводимостью. В такой системе шумы изучаются впервые. Рассмотрены случаи, когда обе поверхности металлические, и когда одна из поверхностей металлическая, а другая имеет активную, емкостную или индуктивную проводимость. Результаты и обсуждение. Показано, что наличие одной поверхности с комплексной проводимостью при второй металлической, не дает заметного преимущества ни в увеличении коэффициента усиления, ни в снижении коэффициента шума по сравнению со случаем обеих металлических поверхностей. Показано, что для получения наибольшего коэффициента усиления и наименьшего коэффициента шума нужен близкий к единице фактор заполнения.



  • Noises in resistive wall amplifier, caused by fluctuations in the electron beam
    , D. I. Trubetskov, A. A. Funtov, , N. V. Chizhmotrya, and
    Saratov State University


  • Some questions of the theory of resistive wall amplifier m-type


  • Interference amplification in an electron-wave tube (Linear Theory)
    D. I. Trubetskov, A. V. Titov, and A. A. Funtov
    Pleiades Publishing Ltd

  • ABOUT APPROXIMATE ANALYTICAL SOLUTIONS OF LOTKA-VOLTERRA EQUATIONS
    Фунтов Александр Андреевич
    Saratov State University
    The possibility of analytical decision of Lotka-Volterra equation is demonstrated for «predator-prey» model, and for comlicated models.