Designing a Beam-Plasma Traveling Wave Tube
The method of equivalent systems is used to simulate resonator slow-wave structures of beamplasma devices. A collisionless plasma is considered as a filler for the drift channel. The adequacy of the model is shown by comparing the calculation results with known experimental data. The dispersion characteristics of slow-wave systems are analyzed. The structure of the high-frequency unit of a beam-plasma traveling wave tube is developed, and the parameters of the tube are evaluated using the VEGA code.
A portable wireless device for recharging batteries of vehicles, phones, and another apparatus is offered and described in this paper. Application of novel antennas, formed by sections of coupled radial spirals with dimensions significantly less than the operating wavelength in free space, makes it possible effective transmission RF energy from one object to another without radiation into surrounding medium.
This paper considers the model of amplification of electromagnetic millimeter waves by non-relativistic electron beams in one-dimensional periodic electrodynamic systems. As slow-wave structures are investigated systems such as “winding waveguide” and “counter-pins”-type suitable for use in the millimeter range. The main directions of research are: - development of a traveling-wave tube model on the basis of the differential theory of excitation of electrodynamic systems by currents; - modeling and calculation for simplified waveguide-resonator model of electrodynamic properties of slow-wave structures such as "winding waveguide" in the millimeter range; - representation of a waveguide-resonator model of "winding waveguide"-type slow-wave structure, composed of segments of rectangular and U-shaped waveguide; - obtaining by a waveguide-resonator model coefficients of the transmission matrix, which allows to analyze the dispersion and coupling impedance in the band of amplified frequencies; - investigation of “winding waveguide"-type slow-wave structure taking into account the geometric phase rotation field in neighboring gaps by linear waveguide-resonator model represented by a chain of quadripoles by means of opposite switching of the induced current in the neighboring interaction gaps and also the first spatial harmonic used in traveling-wave tubes for the calculation of the dispersion; - calculation of a number of options that characterize the basic laws of changes in the properties of “winding waveguide"-type slow-wave structure; - modeling the properties of slow-wave structures such as "winding waveguide" using 3D-codes; - application of the results obtained using the 3D-codes as the numerical experiment to adjust waveguide-resonator model; - model building pin-type slow-wave structures using waveguide-resonator model, customized by experimental reference points. The paper shows that for modeling slow-wave structures such as “winding waveguide” and “counter-pins” waveguide-resonator model customized to the experimentally obtained reference points can be used. As the reference points can also be used the values of deceleration and the coupling impedance obtained by numerical experiment using HFSS. Waveguide resonator models constructed in such way are sufficiently accurate and simple. This paper shows that these models can be successfully used for the calculation of traveling-wave tubes operating in the millimeter range.
Microwave devices designed on the basis of multipole lenses (ring electromagnetic structures using resonant sections of slow-wave structures) are analyzed. The possibility of development on the basis of these lenses of a low-noise amplifier and a microwave multiplier, which ensure long-term interaction of the electron beam and the transversely extended electromagnetic field with continuous extraction of energy, is shown.
The electrodynamic characteristics of the helical slow-wave structure of a high-power pulse traveling-wave tube operating in the centimeter wavelength range are calculated by means of the solution of the dispersion equation and simulation. Special attention is focused on the effect of a helix wire profile on the electrodynamic characteristics of the system. The results of the theoretical study are compared with the experimental data.
The Asia-Pacific Microwave Conference (APMC) is the largest microwave event of its kind in the Asia-Pacific region. APMC provides a broad forum for participants from both academia and industries to exchange information, share research results, and discuss collaborations in the fields of not only microwave but also millimeter wave and even to the far infrared and optical waves. The series of APMC began at New Delhi, India in 1986 and APMC 2018 is going to be the commemorable 30th conference. APMC 2018 will be held at Kyoto International Conference Center (ICC Kyoto), Kyoto, Japan, on November 6-9, 2018. Commemorating its 30th conference, the APMC 2018 Steering Committee plans to hold special events and is privileged to welcome all the colleagues around the world in this special occasion.
In this paper, dispersion characteristics of "serpentine”-type slow-wave structures, which are promising for the terahertz range use, are calculated. For 3D-modeling, HFSS was used. Program described in work was used in the calculation. Using the obtained characteristics, octopole chain model of the slow-wave structure is constructed. Discrete approach is advisable in solving these problems. Justification of the applied mathematical model for the discrete interaction follows from the difference form of electrodynamic theory of excitation . Requirements to coefficients of the resulting finite-difference equation are high, because their accuracy determines how close the mathematical model of the discrete interaction to the physical laws is. These coefficients have a certain electrodynamic sense and are obtained through the octopole transmission matrix coefficients. In turn, this octopole is a mathematical model of the resonator slow-wave structure cell.
A linear theory of the discrete interaction of electron beams and electromagnetic waves in slow-wave structures (SWS) is developed. The theory is based on the finite_difference equations of SWS excitation.The local coupling impedance entering these equations characterizes the field intensity excited by the electron beam in interaction gaps and has a finite value at SWS cutoff frequencies. The theory uniformly describes the electron–wave interaction in SWS passbands and stopbands without using equivalent circuits, a circumstance that allows considering the processes in the vicinity of cutoff frequencies and switching from the Cerenkov mechanism of interaction in a traveling wave tube to the klystron mechanism when passing to SWS stopbands. The features of the equations of the discrete electron–wave interaction in pseudoperiodic SWSs are analyzed.
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.