Diffraction Radiation Generator Research Articles

A setup for measuring characteristics of microwave electric vacuum devices with open resonance structures

A new modification of the universal experimental setup for measuring electrodynamic characteristics of microwave generators with open resonance structures of the orotron-diffraction-radiation-generator type is described. To expand the functional capabilities and the electronic frequency-tuning range, an additional periodic metal-dielectric structure is introduced into the open resonator. The experimental results of investigations of the energy, volt-ampere, and frequency characteristics of the modified diffraction-radiation generator prototype are compared to the characteristics of the generator without a metal-dielectric structure.

Influence of the local inhomogeneity of a magnetostatic field on the start and output characteristics of a differaction radiation generator

We study, both theoretically and experimentally, the possibilities of improving the output characteristics of a nonrelativistic diffraction radiation generator (DRG) by creating a local inhomogeneity of the magnetostatic field (LIMF) in the electron-wave interaction region. The LIMF was created in a homogeneous focusing magnetic field using a ferromagnetic rod. We found relationships for calculation of the main characteristics of the LIMF and showed the dependence of the start current on the size of the rod and its location relative to the interaction region. The theoretical results were confirmed by the experimental studies of DRGs in the frequency range 40 to 170 GHz. It is shown that the use of an LIMF improves the start, power, and spectral characteristics of the DRG. We conclude that the proposed technique is useful for designing lowvoltage generators with improved output characteristics at short millimeter and submillimeter wavelengths.

Investigation of a Diffraction Radiation Generator (orotron) with a Local Magnetostatic Inhomogeneity in the Interaction Space

The possibilities are studied for raising the efficiency of energy-exchange processes and improving output characteristics of a nonrelativistic, diffraction-radiation generator (orotron) (DRG) through introduction of a local magnetostatic field inhomogeneity (LMI) in the interaction space. Formation of the local magnetostatic field inhomogeneity by a ferromagnetic rod and the effect of the inhomogeneity upon excitation of electromagnetic oscillations in a DRG are analyzed theoretically. Meanwhile, the experiment shows that introduction of a LMI in the DRG allows improving its starting, power and spectral characteristics in the frequency range of 40-80 GHz. Here we report on the development of a prototype packaged millimeter-wave DRG based on the idea that is characterized by improved output characteristics compared with the known devices of the kind.

Realization of intermode oscillations in open resonator of diffraction radiation generator

The results of an experimental study of oscillation interaction in the open resonator of a diffraction radiation generator (DRG) are presented. Interaction is obtained in the region of oscillation splitting in the electrodynamic system of the DRG in the diffraction-radiation mode. The possibility of improving the generator's frequency stability in the vicinities of Morse critical points is shown.

Diffraction Radiation Generators in mm Range

ABSTRACT The paper deals with the results of investigations of a new highstable source of electromagnetic oscillations of the EHF range, namely, a diffraction radiation generator (DRG). Its operating principle is based on using the effect of diffraction radiation (Smith-Parcel effect). Technical specification of the DRG and examples of their application in radisystems are given.

Output characteristics of a diffraction radiation generator in the autonomous and nonautonomous modes

Output characteristics of a diffraction radiation generator in the autonomous and nonautonomous modes

Numerical simulation of stationary regimes of a diffraction radiation generator

Numerical simulation of stationary regimes of a diffraction radiation generator

Transient processes in diffraction-radiation generator with frequency modulation of the oscillations

Transient processes in diffraction-radiation generator with frequency modulation of the oscillations

Study of polarization characteristics of radiation from a diffraction radiation generator

Polarization characteristics of radiation from a DRG are experimentally studied. For a proper interpretation of the obtained results, both the internal and external resonance fields of the electrodynamic system of a generator in the cold mode are studied. It is shown that the polarization of the output radiation of the generator changes with an increase in the focusing magnetic field and the beam current. An interrelation is established between the polarization characteristics of the electromagnetic field inside the generator and its radiation field.

The autodyne effect in a diffraction-radiation generator

The autodyne effect in a diffraction-radiation generator

Theory of diffraction-radiation generator on basis of discrete-interaction model

A dynamic nonlinear theory of a diffraction-radiation generator is developed here on the basis of the discrete-interaction model. A thorough comparison is made between energy characteristics calculated according to the discrete-interaction model and according to the wave model. The range of applicability is established for the wave model and some physical data are presented. The theory proposed, with the aid of Fourier integral transformations, allows rigorous accounting for the finite width of slots and the Coulomb repulsion forces.

Unstable resonator and output-coupling design study for diffraction radiation generator near-mm sources

Configurations of unstable resonators that could be used for diffraction radiation generators (DRG's) are presented. The output coupling of a negative branch unstable resonator exhibits an extreme sensitivity to mirror radius and appears to be unsuited to DRG use. The positive branch resonator does not exhibit this sensitivity to mirror radius, and the mirror radii that are needed to give output couplings of a few percent appear practical.

Degenerate oscillations in a quasioptical open resonator with rectangular large-aperture mirrors

The results of this study suggest the following. 1. The spectrum of a precisely fabricated and adjusted open resonator with large-aperture mirrors (2a ≫ λ anda ∼ d) consists of axisymmetric modes when excitation is concentrated along the resonator axis. 2. Alinear combination of modes with rectangular even symmetry corresponds to an axisymmetric mode when the inequality m+n+1=2p+l+1 is satisfied. 3. The degeneracy of modes is effectively removed by insertion of a phase filter into space of the open resonator, or by the use of mirrors with slightly different radii of curvature in mutually orthogonal directions (astigmatic mirrors). 4. Using the well-known method of a test probe for analyzing the spectral content of oscillations in an open resonator [4] requires a certain caution, viz.: it must be remembered that reliable quantitative results will be obtained only for the lowest-order TEM00q mode and for nondegenerate modes with rectangular symmetry. 5. It is expedient to use an open resonator with a “pure” spectrum of natural modes in millimeter-wave devices such as radiospectrometer cells and resonance spaces in diffraction radiation generators, also as active cells in spectrum analyzers of spatial field structures of any configuration.

Theoretical analysis of stationary modes in a diffraction radiation generator with a reflected beam

Theoretical analysis of stationary modes in a diffraction radiation generator with a reflected beam

Investigation of the spectral characteristics of pulses of diffraction radiation

The physical phenomena which lead to distortions of the spectrum of diffraction radiation pulses are analyzed by means of theoretical estimates and experimental investigations. The experimental investigations were carried out for pulses of high-frequency oscillations with a duration of 0.15–10μsec, excited in a diffraction radiation generator in the millimeter-wavelength range. The effect of steepness of the electron frequency retuning, the magnitude of the focusing magnetic field, and the pressure of the residual gases on the spectral characteristics of the instrument is established. The range of variation of the generator parameters is determined, where parasitic effects leading to distortions of the spectrum are expressed only slightly.

Effect of dynamic and static electron displacements on start-up currents of a diffraction-radiation generator

Effect of dynamic and static electron displacements on start-up currents of a diffraction-radiation generator

Millimeter-range diffraction-radiation generator with an open resonator of paired cylindrical mirrors

Millimeter-range diffraction-radiation generator with an open resonator of paired cylindrical mirrors