Analysis of the dispersion characteristics of slow-wave structures with two microwave propagation channels
Models of rectangular and axially symmetric resonator slow-wave structures, which are built using transmission matrix for determining the characteristics of the slow-wave structures in different operation modes, are investigated. Elements of the transmission matrix are determined from the results of 3D simulation with the use of the HFSS software. In the analysis of the dispersion characteristics, slow-wave structures with two microwave propagation channels are studied and simulated using a 4×4 transmission matrix.
Original Russian Text © N.P. Kravchenko, S.V. Mukhin, S.A. Presnyakov, 2017, published in Radiotekhnika i Elektronika, 2017, Vol. 62, No. 7, pp. 693–702.
The results of this study were reported at the 2nd All-Russia Conference on Problems of Microwave Electronics, Moscow Institute of Electronics and Mathematics, Higher School of Economics (National Research University), Moscow, October 26−28, 2015.
In modeling of resonator slow-wave structures, equivalent systems method was used and collisionless plasma was used as the transit channel filler. Comparison of the results obtained demonstrates the accuracy of the developed model. The dispersion characteristics analysis was conducted.
A model of the slowwave cavity structures that can be used for the analysis of electrodynamic parameters and excitation by the fixed current is electrodynamically substantiated. A possibility of the calcu lation of electrodynamic parameters using the 3D simulation is demonstrated for the slowwave cavity struc tures. The calculated electrodynamic parameters of the two and fourport slowwave structures are pre sented.
In this paper the calculation of the dispersion characteristics of the slow-wave structures suitable for use in the terahertz range devices is conducted. The slow-wave structuress of the "winding waveguide"-, "serpentine"- and "counter-pins"-type can be considered as such. Analysis of the dispersion characteristics was carried out using waveguide-resonator model, which is built for slow-wave structures of the "winding waveguide"-type taking into account the channel for the electron beam. The waveguide-resonator model is composed of quadripoles describing the waveguide segments. This model is most accurately reflects the field structure in the "winding waveguide". The second approach is used to analyze the slowwave structures of "serpentine" and "counter-pins"-type. Analysis of the slow-wave structures was performed using the 3D-modelin in program HFSS . The dispersion characteristics were calculated by the program outlined in the work . These characteristics are used to build the model of the slow-wave structure, which is represented in this case by the chain of the octopoles of quadripoles. The discrete approach is the most common for the solution of this problems. Justification of the application of a mathematical model for the description of the discrete interaction follows from the difference form of electrodynamic excitation theory . Waveguide-resonator model is also used in the construction of a model of TWT section with the discrete interaction. High demands are made to the coefficients of the finite-difference equation, because the more accurately they are given, the more adequate the mathematical model of the discrete interaction in a relation to the physical laws. Those coefficients have a definite electrodynamic meaning and are defined via coefficients of the quadripole transmission matrix derived from the sextopole in the absence of the exciting current. This quadripole, in turn, is a mathematical model of the cell of the resonator slow-wave structure.
The results of numerical simulation of electrodynamic characteristics of a slow-wave structure shaped as a folded waveguide and an electron–optical system of a three-millimeter-band pulse travelling wave tube with an output pulsed power of up to 50 W are presented. The matching devices, the interaction space, and the electron–optical system are calculated, which allows determination of their constructive parameters. The effect of loss caused by the roughness of the surfaces of the walls of the electrodynamic system on the output characteristics of the device is estimated.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.