2007 International Kharkov Symposium Physics and Engrg. of Millimeter and Sub-Millimeter Waves (MSMW)

The present report discusses experimental results obtained in an effort to compare the diffraction radiation oscillator operation features in the case of the excitation on the first, second and third space harmonics of the reflecting diffraction grating accommodated in the interior of the same open resonant system (ORS). It will be shown that a reasonable ORS choice provides the DRO excitation on ... View full abstract»

In this paper, the low-voltage pulse orotron generators of the short millimeter and long submillimeter waves with power level up to 1 W have been developed. Some methods of frequency and power enhancement are proposed. View full abstract»

A new linearization technique is proposed that compensates 3rd-and-5th-order intermodulation distortion (IM3 and IM5) simultaneously by using Cuber Predistortion and 2nd harmonics injection. Due to the use of predistortion, the power amplifier (PA) can be linearized at lower output back-off values and smaller drain currents than possible with the PA using conventio... View full abstract»

It is shown that the output power on the second space harmonic may be comparable with that on the first space harmonic at one-wave DRR regime. The possibility of the orotron OPS period increasing and tooth grating width increasing even operating only on the second space harmonic is demonstrated. The 3 times tooth grating width increase will allow to improve the hardness of small size OPS. Thus it ... View full abstract»

Until recently, development of new gyrotrons focused mainly on the increase of their operating frequency, power and efficiency. The power level of modern cw gyrotrons has reach 1 MW and there is an evident tendency further increase their output power to at least up to 1.5-2 MW.It is evident, that there are rather significant reserves for decrease of the losses and appropriate enhancement of the gy... View full abstract»

A possible chaotic behavior of electrons moving in the pump magnetic field of a hybrid planar ubitron may seriously influence its operating regimes. It turns out that some answers to the posed questions can be provided even in the framework of the linear theory. View full abstract»

The efficiency of powerful gyro-devices strongly depends on the quality of helical electron beams (HEBs) used as an active media for RF generation. The most popular system to form HEB is the magnetron-injection gun (MIG). In MIGs one of the most important factors influencing on the quality of HEBs is the reflection of particles from the magnetic mirror near the cavity. Influence of the pulse form ... View full abstract»

In this paper, theoretical investigations of the auxiliary cathode operation in magnetrons with secondary-emission cold cathode have been performed. It is shown that in the current magnetron design, the emission current of the auxiliary cathode depends on the temperature. It is also shown that a spatial-charge limited emission regime of the auxiliary cathode operation can be realized by introducin... View full abstract»

This article reports the enhancement of coaxial gyrotron backward-wave oscillator (gyro-BWO) efficiency due to local variation of magnetic field that prolongs stay of electron bunch in retarding phase of TE₀₁ mode field. The temporally averaged efficiency of the gyro-BWO is investigated for homogeneous and non-homogeneous guiding magnetic fields. View full abstract»

This report aims to compare the motion trajectory of charged particles in crossed-field systems with both smooth and cavity anodes. To solve this problem, it is necessary to find the distribution of electrostatic potential in smooth and cavity anodes. Calculations of charged particle trajectory under these conditions are presented. View full abstract»

Presented in this work magnetron-injection gun (MIG) was developed for operation in anode range from 2 to 6 kV and electron current up to 300 mA with pinch parameter varying from 2 to 4. The results of the experimental and theoretical investigations of the influence of magnetic field mirror and the influence of beam space charge on beam parameters are presented in this paper. Now we carry out expe... View full abstract»

In this paper, analysis from experimental results showed some regularity in microwave discharge behavior and in signal propagation along transmission line. Microwave discharge in thin (conductor diameter three times less then oscillator wave length) single conductor transmission line represents erosion discharge of torch type. Material consumption and brightness temperature of conductor sputtering... View full abstract»

In the course of development work on designing millimeter-wavelength magnetrons, many attempts had been made to achieve the regime of interaction between an electron flow and a spatial harmonic of one of the doublet-type oscillation modes. The techniques for establishing the causes that restricted the extent of oscillation in modes for the magnetic field non-pi-mode magnetron and determining the c... View full abstract»

The low-voltage DRO development at the short-wave end of the mm region requires recognition of the prospects for enhancement of the DRO with a thick electron beam. For this purpose, the potential of "klinotron" excitation regime, magnetostatic field profiling and enhanced gratings is studied. The present work reports test specimens of the 50-80 GHz DRO whose focusing field carries a local magnetos... View full abstract»

Sources of intensive coherent short-wave radiation up to X-ray can be created by radiation of high numbers harmonics by an ensemble of nonrelativistic oscillators moving in periodically inhomogeneous medium or in external space-periodic potential. The mechanism of harmonics excitation is investigated in a microwave range. View full abstract»