ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)


Innovations in applied physics

Wave processes in the electron beam in crossed static electric and magnetic fields as it moves in a medium with a complex conductivity

Resistive wall amplifier is vacuum microwave device. The gain is due to the phase shift between a.c. of electron beam and the alternating field components. The absorbing device walls influence on the alternating field components is considered. It is interesting that there is no need for a slowing system that is important to learn the submillimeter range. Furthermore the feedback is completely absent between the output and the input.

W-band relativistic gyrotron project with 5-10 MW output power

The 3-mm band relativistic gyrotron excited by 250 keV electron beam with record output parameters (power 5–10 MW, efficiency 35–40%, microwave pulse duration 0.5–1 µs) was developed. The main design solutions of components, such as the electronoptical system forming helical electron beam, the interaction space and the electrodynamic system of microwave output, are presented.

The influence of the azimuthal inhomogeneity of electron beam–microwave interaction on the operation regime of subterahertz gyrotrons

The investigation of operation regimes of CW/263 GHz/1kW gyrotron, developed at IAP RAS/GYCOM Ltd., was made by various numerical methods. The influence of the azimuthal inhomogeneity (such as electron beam radial misalignments and tilt) has been studied. The method of average equations and 3D PIC codes (CST Studio Suite and KARAT) were used. Results, achieved by different methods, are in agreement with experimental data. It is shown, that for feasible values of asymmetry, relative efficiency reduction can reach 40% from initial value.

Control of the electromagnetic spin waves spectrum in a heterostructure based on the lateral system of magnetic microwaveguides

At present, the actual task is to study magnetic microstructures, the characteristics of which can be controlled by changing static magnetic and electric fields. Thin films of yttriumiron garnet show much lower damping of spin waves in comparison with metallic magnetic films. The propagation length of spin waves in magnetic microwaveguides and magnonic crystals is of the order of a few millimeters at room temperature. The use of lateral magnetic microstructures is important for the development of interconnection elements in planar topologies of magnonic networks.

Automodulation and chaotic regimes of generation in a two-resonator gyroklystron with delayed feedback

Topic and aim. The dynamics of a double-resonator gyroklystron of the 93 GHz band with delayed feedback is studied. A comparative analysis of the dynamical regimes of amplifier generation obtained in the numerical experiment both on the basis of averaged equations and in the framework of direct numerical simulation by the «particle-in-cells» method using the KARAT code is carried out. Method.

Effect of low-frequency noise signal on microwave oscillator of deterministic oscillation at si–ge transistor

Aim of this work – to show the possibility of oscillation chaotization at the effect of low- frequency (0.1...3.0 MHz) noise signal both on feed circuit of IMPATT diode in one-frequency IMPATT diode oscillator (IMPATT-DO) and on feed circuit of transistor in one-frequency transistor oscillator. It supposed to confirm the assumption, said early, that this effect, found by us in first time for one-frequency IMPATT-DO, can take place for any semiconductor oscillators with p–n-transition, more exactly, it’s nonlinear current-voltage characteristic. Method.

Development of field emitters for short wave microwave devices and their investigation in spbpu. The last achievements

Topic and aim. The data on the latest achievements of authors on the development and investigation of field emitters for electron-beam microwave devices of millimeter and submillimeter wavelengths range are presented. Methods. The methods for creating and characteristics of new type cathodes, that are of great practical interest, are described: multi-tip silicon cathodes with two-layer metal-fullerene coatings and multilayer nano-structured cathodes, whose emission is determined by the fields at the contacts of materials with a different work function.

Differentially coherent information transmission based on chaotic radio pulses

Subject of the study. Differentially coherent information transmission scheme using chaotic signals as carriers - DCSK (Differential Chaos Shift Keying) was proposed as an alternative to communication systems based on chaotic synchronization. It is resistant to noise and other disturbances at the same level as classic transmission systems based on regular signals. However the requirement of using long time delay lines makes difficult practical implementation of wireless communication systems based on DCSK.

Noises in resistive wall amplifier, caused by fluctuations in the electron beam

In this paper, noise in resistive wall amplifier – vacuum microwave device is studied, in which in which the gain is due to the phase shift between the electron beam and the alternating field components due to the presence of absorbing walls. It should be noted that in resistive wall amplifier, there is no need for a slowing system and that almost completely there is completely lacks the feedback between the output and the input. Recently, attention has been paid to it, in particular, because of the possibility of using metamaterials that increase the gain factor.

About possible theoretical approach in the linear theory of dielectric twt and devices containing metamaterials

In this paper we present overview of devices using a dielectric as a slow-wave structure. There are increased focus on consideration of dielectric Cherenkov maser (DCM) and resistive-wall amplifier (RWA). This type of devices may be advance in THz range. The principle of the DCM operation is described by two-dimensional planar model with the indication of main advantages of this device. In particular, there are sufficiently large gain and possibility of great tunability range (by varying the beam voltage).

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