V. S. Miroshnichenko

Determination of Oscillation Parameters of Open Resonator Systems using Fractional-Rational Approximation by Continued Fraction

Open resonators (OR) are one of basic elements of modern systems and devices of millimeter and submillimeter wavelength ranges. The one-port network presentation of the coupling OR, and processing of the measurements of complex reflection coefficient by linear-fractional approximation allows one to determine oscillation parameters of single resonance in open resonance systems at presence of radiation losses in coupling ports.

Investigation of the Resonance Field Structure in an Open Resonator by the Probe Method: Theory and Experiment

The mode structure in a 2D open resonator is reconstructed with the probe method in numerical and full-scale experiments. The domain of applicability of this method, which is specified by the continuous variation of the eigenmode phase in the open resonator, is found. A probe-induced change in the diffraction Q factor of the eigenmode does not necessarily meet its amplitude distribution in the open resonator. The potential of the probe method for estimation of the energy characteristics of modes in open resonators is discussed.

Formation of super-gaussian fields in open two-mirror resonators

The characteristics of excitation of oscillations in the open resonator (OR) with super-Gaussian fields, as a resonant system of diffraction radiation oscillator (DRO) in THz have been considered. The results of theoretical researches of the spectral distribution and the structure of fields in two-dimensional OR and experimental evidence of modes of excitation in three-dimensional OR with super-Gaussian fields are shown.

Method of resonant matching in diffraction radiation oscillator with a double comb

The resonant matching instead of the traditional phase matching of the double periodic grating substantially changes the resonant oscillation field structure in the ORS as DRO part. On the other hand, the double periodic grating at the bottom of the rectangular groove acting as a quarter-wave transformer enhances the resonance field utilization by the electron beam and effectively removes high-order modes, enabling us to further advance to the terahertz region. When the matching groove height is chosen to be b = 0.75λ , quite a wide tuning range is possible to achieve for the working oscillation with a high radiation quality. A larger factor of resonance field utilization in the ORS is due to the resonance field contraction to the ORS axis in the mirror space rather than the field amplitude growth in the double periodic structure, and it will not increase the ORS ohmic loss.

The experimental investigations of dro-orbictron in 8-MM waveband

The experimental researches of DRO-orbictron mainly confirmed the conclusions of theoretical researches and showed perspective of the use in DRO resonance matching method of double grating with the ORS-field. The placing of double grating on the bottom of the matching groove gives the opportunity in substantially decreasing of ORS-mirrors aperture, and we can excite in the ORS only the basic TEM00q-modes. The increasing of efficiency for energy exchange between an electron beam and resonance field in DRO-orbictron is caused by gathering of the resonance field to the width of matching groove and do not accompanied by the growth of ohmic losses in a resonator. At the choice of the matching groove height to b ≈ 0,75λ the width of one-mode frequency tuning for DRO-orbictron exceeds 5,5%, and the output power arrives P = 10Watt at the beam current Ia = 130mA and the accelerating voltage Ua = 2,9 kV. The carried-out experimental researches of DRO-orbictron showed a perspective of use the given ORS in short-wavelengths DRO.

Excitation of diffraction radiation oscillator with double grating on higher space harmonics

The experimental researches of the diffraction radiation oscillators (DRO) in millimeter waves range with the double periodic grating optimized for operation on the higher space harmonics are presented. The field amplitude magnification in a grating is revealed under a grating period increase.

Mode excitation in DRO with phase shift of the field in the middle of interaction space

The experimental results on mode excitation in the diffraction radiation oscillator (DRO) with phase inversion of a field of the open resonant system (ORS) in the middle of interaction space are presented. The DRO for 5-mm wavelength worked on a TEM01q-mode with output power 3divide5 Watt in a wide band of frequency tuning. 4-5 timespsila increase of starting current for a competitive surface mode of oscillations in comparison with homogeneous grating was observed.

Ohmic Losses Influence on Excitation of Diffraction Radiation Oscillator on High Order Space Harmonics

The report discusses experimental results obtained in an effort to compare the DRO operation features in the case of excitation on the first, second and third space harmonics of the reflecting diffraction grating placed inside the same open resonant system (ORS). It will be shown that the choice of ORS provides DRO excitation on the high-order space harmonics almost without the starting current increasing.

Scalar Meausurement Technique of Coupling Coefficient of diffraction Radiation Oscillator

The technique of scalar measurements of coupling coefficient and Q-factor in open resonant systems (ORS) is offered in view of radiating (non resonant) losses in the coupling hole. Various techniques for measurement of coupling coefficient of diffraction radiation oscillator (DRO) have been compared

Diffraction Radiation Oscillators with Low Consumption

A new design and experimental research results of physical characteristics of the diffraction radiation oscillator in 5-mm wavelength range with lowered accelerating voltage of 600-1000 V are presented