Radio physics and electronics

10-17

Authors: V. K. Ivanov, A. Ya. Matveev,V. N. Tsymbal, S. Ye. Yatsevich, D. M. Bychkov

Atmospheric dust is a mixture of minute particles of various salts and minerals; it also contains the remains of plants and animals, spores of pathogenic microbes, etc. The winds carry the dust over long distances, and its presence in the atmosphere is one of the factors that significantly affect the planet's climate. Currently, for space monitoring of aeolian processes and their consequences only multispectral optical systems are used (TOMS, METEOSAT, MODIS, etc.); they cannot identify the areas which are the sources of raising dust in the atmosphere regardless of clouds, brightness and transparency of the atmosphere. This problem can be solved by the space remote sensing radar systems. The article presents the first results of processing the method of radar identification of desert areas in which under the influence of aeolian processes the process of raising dust from the surface to the atmosphere takes place. The testing was performed using the data of radar remote sensing of Mauritania deserts of SAR Envisat-1. The peculiarities of manifestation of focused backscattering of radio waves in radar images at different speeds of surface wind, surface radar radiation and wind directions were analyzed. It is concluded that applying the radar remote sensing to identify areas raising dust in the atmosphere is effective. The results of the study allow to create new methods of remote monitoring of processes in desert areas, affecting the climate of vast regions of the Earth.

24-30

Authors: A .V. Dormidontov, Yu. V. Prokopenko, V. M. Yakovenko

One of the urgent problems of modern radiophysics is the study of the fundamental properties of solid-state structures that contain nanodimension fragments. Studies of the excitation mechanisms of electromagnetic waves when the charged particles move in various electrodynamic systems form the basis of electronics. In this case, a number of the fundamentally important characteristics of structures include their dispersion equations. They allow to determine the place of electrodynamic structures in the radio physical systems of different purposes. An energy loss of a charged particle per unit time on the waves and/or oscillations excitation in the system is the data characteristic. In electrostatic approximation the dispersion equation describing the eigenmodes of semiconductor cylinder with the layer of two-dimensional electron gas on the side surface (3D+2D-plasma) has been obtained. The energy loss of charged particle was found when it was moving in external magnetic field that has the intensity vector parallel to the symmetry longitudinal axis of the 3D+2D-plasma of cylindrical configuration. It was noted that the obtained relation has the universal character. With the help of it the energy loss may be determined for rotary motion of particle around the cylinder and its translational motion parallel to the cylinder generatrix. The effect of non-reciprocity of the eigenmodes excitation of 3D+2D plasma cylinder was discovered. These modes have identical structures of the field distribution, but differ in the propagation direction along the azimuthal coordinate. Research results extend our conceptions about the electrodynamic properties of systems with plasma mediums and systematize the knowledge of the excitation mechanisms of electromagnetic waves in electrodynamic systems that form the basis of microwave devices.

39-44

Authors: O. V. Sytnik, S. A. Masalov, G. P. Pochanin

The actual problem of measuring the thickness of the surface layers of the soil using GPR radar systems under stringent restrictions on the minimum length of a video pulse and under the presence of the noise caused by resonance effects in antenna and multiple reflections of the sounding signal from the boundaries between media has been studied. Traditional extreme correlation signal processing methods do not provide the resolution less than half of the total duration of the pulse. To overcome this limitation is possible by using nonlinear methods, for example the homomorphic signal processing. The possibility of high resolution of subsurface stratified media boundaries by using non-linear homomorphic digital signal processing of reflections is proved theoretically and experimentally. The proposed method has used the non-linear spectrum transformation of ultra wideband sounding signals. It allows getting resolution approximately to 5 % of pulse duration instead of limitation of the traditional correlation method of signal processing. The FFT algorithm is used to calculate the amplitude spectrum of the signal, the result is subjected to logarithms and then the inverse Fourier transform is computed, to get a signal's cepstrum containing the probe signal and digital signal delay. The analysis of cepstrum at a relatively high signal to noise ratio allows one to calculate the estimate of the thickness of the layer. The results of simulations and experimental data processing are also shown.

54-61

Authors: K. A. Lukin, P. P. Maksymov

The actual task of semiconductor electronics is development and creation of diode generators of microwave power on the basis of active elements with the extended functional possibilities. It is shown that avalanche-generator diodes (AGD) on the basis of abrupt p–n-junctions with constant voltage of the reversed bias are the generators of microwave power. The theoretical analysis of mathematical model of AGD is based on the decision of the complete system of equalizations of diffusive-drifting model describing physical processes in a diode taking into account the influence of charge of mobile carriers on the electric field. A limiting cycle and invariant torus is certain in the phase plane of AGD. It is shown that at high voltage of the reversed bias on abrupt p–n-junctions in AGD there is an internal feed-back between the electric field and avalanche current, resulting in current instability and generation of two-frequency oscillations. The results of theoretical analysis of AGD can be of practical interest to developers of powerful dual-frequency sources of electromagnetic waves of microwave range.

70-79

Authors: V.V. Glamazdin, M.P. Natarov, V.N. Skresanov, A.I. Shubnyj

The application of open resonators in the measurement technique or in the generator oscillation systems requires taking into account the influence of coupling elements (CE) on the open resonator (OR) characteristics. The additional radiation loss takes place under the OR excitation or energy output process. It is not known about investigations of such loss in mirror dielectric disk resonators (MDDR) with whispering gallery modes, which are the type of OR. The results of experimental investigation of the radiation loss of the MDDR CE with matched waveguides are presented. Two methods of measurements, the impedance method and the method of power balance, were modified for application to MDDR and used for investigations. Two types of CE have been studied: the hole in the thing metal wall on the surface of the MDDR mirror which is connected to the rectangular waveguide and the narrow slot on the mirror surface which is smoothly transformed to rectangular waveguide. The results of radiation loss characteristics measurements, their dependence of sizes and disposition relative to the disk are presented. Comparison of the characteristics of different CE has been made. It has been shown that slot CE have higher efficiency, both excitation and output, than hole CE.

87-91

Authors: A. Ya. Kirichenko, G. V. GolubnichayaPARTICULARITIES OF INTER-TYPE INTERAC

Disc dielectric resonators with whispering gallery modes are usually characterized by high Q-factor, nevertheless, dense spectrum of these oscillation is the factor which impedes their use as microwave elements. In particular, inter-type interaction of oscillations results in the distortions of amplitude-frequency characteristics. The investigation of particularities of this interaction allows one to understand conditions when they appear and find the possibilities to avoid them. The particularities of inter-type interaction in disk quasioptical resonator, excited at high azimuthal modes, in the case of internal excitation of parasitic oscillations in single disk are investigated experimentally. The influence of parameters of coupling element between the resonator and dielectric waveguide on the resonance characteristics is studied. It is shown, that this influence can be compensated by introducing the additional irregularity. Also it is demonstrated, that parameters of two-hump resonant characteristic strongly depend upon azimuthal position of this irregularity. Till the present time the intermode interaction was investigated only in the case of external excitation, using two disk dielectric resonators. The obtained results can be used as a method for selection of disc dielectric resonator oscillation spectrum.

98-101

Authors: O. I. Bilous, N. V. Bryuzginova, S. P. Siren ko, A. I. Fisun

UHF-radiation is used in medicine for medical treatment and diagnostic. Low-level and super low-level radiation influence is named as the information one. In this case the heat balance of bioobjects is unchanged. The UHF-autohemotherapy with microwave blood activation is one of the ways of the present-day physiotherapy. In this paper it has been proposed to monitor the efficiency of this physiotherapeutic procedure by means of testing the electrophoretic mobility of nuclei of buccal epithelium cells. The set of the experiments is carried out for the purpose of corroboration of the possibility to make an estimation of the neurological pathology treatment in traditional medical way and by the UHF-autohemotherapy.

11-21

Authors: V. N.Skresanov, V.V.Glamazdin

A method is proposed for measuring the Q-factor of microwave resonators, which allows the study of microwave properties of materials and environments using open resonators of different types under conditions of availability of close-frequency modes in the surroundings of the given mode, the radiation losses of coupling elements and crosstalk between them. Measurement of the loaded Q-factor is based on both the representation of the frequency dependence of the resonator complex reflection or transmission coefficients by the sum of fractional-linear complex functions, describing the responses of individual modes, and approximation of a square measured frequency response by means of the variation gradient method. The eigen Q-factor calculation method is based on calculation of the resonator impedance on the measured reflectance modulus. The developed algorithms for processing measurement data are implemented in a computer program and are illustrated by the example of the processing frequency dependences of S-parameters for the open dielectric mirror resonator excited with whispering gallery modes, when the S-parameters are calculated by finite element method. Measuring quality factors by the proposed method eliminates the systematic measurement error associated with the distortion of the resonance curves, and makes it possible to perform measurements in conditions where classical methods are unsuitable.

30-37

Authors: A.P. Nickolaenko, Yu.P. Galuk, M. Hayakawa

Investigations of link between parameters of global electromagnetic (Schumann) resonance and characteristics of vertical profile of atmospheric conductivity remain an actual problem. We use a rigorous solution of the electrodynamic problem in the spherical Earth-ionosphere cavity by the full wave technique and compare the results with the knee model, as introduced in the literature. The vertical conductivity profile of the atmosphere was constructed by using parameters of this model, and this allowed us to build the rigorous electromagnetic solution, and to compute the energy spectra of the vertical and horizontal electric magnetic fields corresponding to the uniform distribution of the global thunderstorms over the planet. It is shown that the knee model, discussed in the literature, does not match the rigorous full wave solution and the subsequent computations of the power spectra of Schumann resonance.

49-54

Authors: A.E.Kogut, R.S.Dolia, S.O.Nosatiuk,He Jaochan

The spectral and energy characteristics of the shielded halfspherical resonator at the forced oscillations mode are investigated experimentally at using of the slot-line. It is shown that the use of slot-line allows maximally rarefying the spectrum of forced oscillations of the shielded resonators with an exceptional allocation of whispering gallery modes and achieving the greatest Q-factor. The experimental investigation and computer simulation show that the slot-line is a channel waveguide having the resonance properties.

62-65

Authors: A. S. Vakula

Magnetic nanoparticles are used extensively in various areas of science and technology due to ability to vary their parameters over a wide range. Magnetic properties of the nanoparticles depend strongly on technique of synthesis. The impact of various techniques of synthesis on the magnetic properties of the nanoparticle is not studied well now. Therefore, in this paper the microwave magnetic properties of the Fe3O4 nanoparticles prepared by various techniques of chemical synthesis are under research. The magnetic properties are studied by the ferromagnetic resonance technique at T = 77…300 K. It is shown that the resonant frequency increases when the diameter of nanoparticle rises. The diameter depends in turn on the technique of synthesis. Also it is shown that when the temperature increases the resonant frequency and linewidth are decreased. The results of investigation can be used to select an optimal technique of synthesis of Fe3O4 nanoparticles with specified magnetic properties.

72-78

Authors: O.V.Zemlyaniy

Application of chaotic signals in modern radar and telecommunications is an actual task that can significantly extend the functionality of these systems and improve their performance. In this paper, a method for information transmission using chaotic signal generated by nonlinear dynamical system with delayed feedback of ring type has been suggested. Modulating information sequence controls the parameter of non-linear element, so that it switches the chaotic modes and changes the spectral structure of the signal transmitted to the communication channel. A non-coherent reception was used for demodulation of the received message. The effectiveness of this method of information transmission for the covert operation of communication system in a complex interference environment has been shown.

90-95

Authors: I. P. Storozhenko

The use of variband semiconductors in uniformly doped devices with the effect of intervalley electron transfer can lead to the appearance of a static electric domain. The interest in the static domain is due to the possibility of creating a local electric field sufficient for impact ionization of zone area. Diodes with avalanche ionization in the static domain can be used as active elements of noise generators. The article analyzes the process of formation of a static domain and avalanche multiplication of current in it on the basis of the two-temperature model variband AlGaAs. It is shown that for the formation of a static domain at room temperature, it is necessary that the minimum value of the energy gap between the G-valley and the closest by energy side valley was smaller than the thermal energy of the electrons at the rate of change of the energy gap to coordinate more than 150 eV×cm–1. Accordingly, in devices based on Al0.36Ga0.64As–GaAs cathode static domain is formed, and on the basis of GaAs–Al0.36Ga0.64As anode static domain is formed. The variband semiconductor compounds in which it is possible to form a static domain were determined. Using variband compounds Al0.36Ga0.64As–GaAs with low levels of doping in the vicinity of the cathode increases the effective and integral current multipliers as compared to GaAs-diode. The findings expand the knowledge of the physical processes of charge transport in complex semiconductor structures. They can be used for technological development of new high-speed devices, such as transistors, Gunn diodes, diodes with a stationary domain, avalanche-transit diodes, frequency multipliers.

9-14

Authors: E. M. Ganapolskii

In this paper for the first time we have discovered and studied the analogy of the second order phase transition in spheri-cal microwave cavities with heterogeneity in the form of a metal ball. The transition occurs between the state when the ball is sym-metrically disposed relative to the side walls and the state with asymmetric arrangement of the ball. For these states the spectra of oscillations in 8-mm range were measured and on the basis of the obtained data the correlation coefficients of inter-frequency inter-vals were determined. It has been established that an integrable system of spherical symmetric cavity with an inner ball has a cor-relation coefficient close to zero, while for non-integrable systems with asymmetric arrangement of the ball, the correlation coeffi-cient C(1) > 0.2. Phase transition between these states occurs in a narrow range of eccentricity. The dependence of the distribution of inter-frequency intervals on the mean distance between the natural frequencies were determined and it was found that for an integrable system, this dependence is described by the Poisson function, and for non-integrable by Wigner distribution, which is typical for states with repulsion resonance lines and quantum chaos. Thus, it was found that a change in the symmetry of the microwave resonator leads to the second order phase transition, when the system becomes non-integrable cavity and is accompa-nied by quantum chaos.

20-31

Authors: A. Ya. Matveev, A. A. Kubryakov, A. G. Boev, D. M. Bychkov, S. A. Velichko, V. K. Ivanov, S. V. Stanichny, V. N. Tsymbal

In the article the validation of the multiangle method for spaceborne radar diagnostics of oil pollutions on the sea surface are described. The validation was performed by comparing the radar estimates of the mass and thickness of the polluted oil film with the numerical simulation results obtained by the new Floating Object Tracking System (FOTS) model of oil drift dynamics. Synthetic aperture radar (SAR) satellite Envisat-1 data of the oil-producing area “Oil Stones” in the Caspian surveillances were used for the analysis. FOTS model allows us to calculate the displacement and changing in the mass and size of the oil slick basing only on available satellite measurements and atmospheric reanalysis data. The model takes into account the main processes impacting on the oil slicks dynamics (gravitational spreading, advection transport, dispersion, emulsification, turbulent mixing and evaporation). The model allows to calculate the changes in thickness, and the oil slick displacements in the timeslot between two consecutive radar images, and to estimate spilled oil volume. Satisfactory agreement between the oil film thickness that was calculated by using radar measurements and oil drift model results is observed, which confirms the reliability of the radar multi-angle method. The work was performed as a part of the project 11140 with European Space Agency (ESA) and was supported by the Federal Target Program 1.2 “Study on the technology of monitoring and forecasting the water environment ecological state of the sea shelf: Agreement with the Russian Ministry of Education 14.604.21.0044”

40-47

Authors: Yu. P. Galuk, A. P. Nickolaenko, M. Hayakawa

The rapid development of computer technology allows for the direct numerical solution of the electromagnetic resonance problem in the Earth–ionosphere cavity. Either the two-dimensional telegraph equations (2DTU) or the finite element method in the time domain (FDTD) techniques are used. The direct solutions apply the same models of the conductivity profile of atmosphere as those applied in ordinary solutions. However, it is forgotten that these profiles are nothing else, but a convenient interpretation for the approximate heuristic relations for deriving the propgation constant. Since the full wave solution of the electromagnetic problem for such a profile does not coincide with the aproximate one, the direct numerical solutions must also deviate from the heuristic one. We apply the knee conductivity profile in the rigorous full wave solution and in the approximate solution and evaluate their devations

54-60

Authors: M. V. Milcho

There is a problem of designing convenient in use and not particularly expensive oscillators for mastering the sub-millimetre waveband. The backward wave oscillators (BWOs) provide good results in the long-wavelength part of the sub-millimetre waveband. However, their advancement in the short-wavelength part of the sub-millimetre waveband causes substantial problems. Existing technological opportunities do not allow to obtain extremely thin high-current-density electron beams necessary for this waveband. Application of the frequency multipliers could weaken requirements to the electron beams considerably. A clinotron-type oscillator can be used for bunching electron beam in the frequency multiplier. In the clinotron oscillator, a wide and comparatively thick sheet electron beam is directed at a small angle to the surface of the slow-wave structure and is partly dispersed on this surface. Clinotron provides output powers a few orders of magnitude greater than conventional BWOs of the same waveband. This is important for obtaining good (i.e., deep) bunching of an electron beam. In clinotron-type oscillators, it is necessary to investigate the process of dense electron bunching and to clarify the conditions of its use for bunching electron beam in a frequency multiplier. In this article, numerical simulation of electron bunching is conducted in the clinotron by means of our previously in-house designed special computer program, which takes into account the specifics of the clinontron operational regime. Three-dimensional motion of electron is investigated in the finite focusing (guide) magnetic field. As a result of numeral simulations, we find the effect of “layer-by-layer” bunching of the electron beam in a clinotron-type oscillators. The farther an electron layer is located from the surface of the slow-wave structure the later electron bunching in that layer occurs. We show that singling out the clinotron operating regime and the slope angle of the guide magnetic field to the surface of the comb allows one to ensure the formation of dense electron bunches in the part of the beam outside the clinotron slow-wave structure, where the second slow-wave structure (working in the power-catching regime) must be located. Thus, the principal possibility of the clinotron use for designing a frequency multiplier is proved.

68-72

Authors: A. A. Kurayev, V. D. Yeryomka, A. O. Rak

The equations of excitation of waveguides and resonators by foreign sources are used for solving problems in electrodynamics, microwave and terahertz electronics. The authors of several monographs describe the algorithm for solving the problem of excitation, presenting a waveguide (or a resonator) in the area of foreign currents as a regular one, and as a result in terms of orthogonality of eigen modes of regular waveguide in this area. In reality, foreign currents are set on excitation elements (pins, loops, slots and apertures in the sides of a waveguide or resonator), which transform the mentioned electrodynamics systems into irregular, diffraction and wave scattering take place in the area of foreign sources. Therefore, the well-known equations of excitation from the mentioned monographs cannot be applied for solving problems on excitation of irregular electrodynamics systems by foreign sources. In vacuum electron microwave devices this limitation is removed: foreign electric currents are formed by free electrons currents and excitation elements i.e. slots, loops and apertures are absent. However, there is another obstacle: in vacuum sources of microwave radiation unlike passive electrodynamics, the areas of excitation are not fixed in space, that is why transversal electrons phasing takes place. In this paper we formulated equations of excitation of waveguides and resonators by electron currents under transversal electrons phasing. Application of these equations considerably expands the area of solved problems in electrodynamics and vacuum microwave electronics (in particular, in electronics of gyro devices of new type).

78-82

Authors: V. P. Radionov, P. K. Nesterov, V. K. Kiseliov

Terahertz lasers are used as sources of radiation in different heterodyne radio physical devices. Stable frequency difference between the heterodyne and signal channels is required when using these devices. This paper describes the various ways of solving this problem. A scheme of terahertz laser with several resonators is chosen as an optimal solution. The technique of obtaining and stabilizing the difference frequency in each resonator has been proposed. This multi-line laser can be used in conventional schemes of the interferometers and polarimeters. This laser can also be used in other multichannel systems to obtain a simultaneous radiation with different frequency in channels. The frequency difference is restricted by an amplification band of a laser medium. This gives new possibilities for the application of THz lasers in measuring systems.

90-96

Authors: K. A. Lukin, D. N. Tatyanko, Y. A. Shiyan, L. V. Yurchenko, A. V. Bazakutsa

The paper presents the creation results of the optical low-coherent reflectometer based on spectral interferometry with a heterodyne frequency transfer into the radiorange that allows to measure distances of tens of kilometers. The reflectometer layout for micro-distances based on fiber-optic Fabry-Perot interferometer and broadband infrared source was designed, fabricated and tested. Based on these investigations the feasibility and advisability of using the low-coherence spectral interferometry method for reflectometry measurements of distances for fiber-optic communication lines was demonstrated.

13-25

Authors: A. V. Brovenko, A. A. Vertiy, N. P. Melezhik, P. N. Melezhik, A. Ye. Poyedinchuk

A numerical analytical method of the reverse problem solution is suggested for the relative permittivity profile of layered inhomogeneous media to be obtained from the frequency dependence of the reflection coefficient of a monochromatic plane electromagnetic wave. The idea of the method is to reduce the initial reverse problem to the optimal control problem of the Riccati equation. The solution scheme employs a numerical analytical method for the direct problem solution of monochromatic plane wave diffraction by layered inhomogeneous media and takes advantage of some algorithm developed for smoothing the gradient of the residual functional. With the algorithms elaborated for solving the direct and reverse problems of wave diffraction by layered structures, a series of numerical experiments has been performed, the efficiency of the suggested approach in not a direct determination of layered structure parameters is demonstrated.

32-39

Authors: A. P. Nickolaenko, M. Hayakawa

We model an effect on the Schumann resonance signal recorded in Japan of the ionosphere non-uniformity centered above the earthquake at Taiwan. Changes in the resonance spectrum occur due to interference of the direct radio wave with one reflected from the ionosphere modification above the earthquake. The first part addresses typical models of ELF radio propagation constant and connects it with the vertical profile of atmospheric conductivity. The profile with a knee is analyzed, which is widely used for modeling the Schumann resonance. The four models are included suggested in literature for obtaining the frequency dependence of complex propagation constant of ELF radio waves. It is assumed that the pre-seismic and seismic activity locally reduces the height of the lower-boundary of the ionosphere above the earthquake. The maximum reduction reaches 20 km, and the horizontally symmetric perturbation is described by Gaussian curve having the scale of 1 000 km.

48-57

Authors: V. K. Ivanov, A. Ya. Matveev, V. N. Tsymbal, S. Ye. Yatsevich

Aeolian processes transporting sand and dust is a powerful erosive force that shapes the structure of the surface of the vast territories and loads the atmosphere with aerosols suspended dust spread by wind over long distances. The presence of atmospheric dust in the environment of the planet is one of the factors significantly affecting the temperature and climatic conditions of vast regions. There are no published data on the characteristics of the radio waves scattering features manifested in radar studies of aeolian sand and dust transport processes in desert regions, which can be used for determining the parameters of a remote transport. The article presents the results of the analysis of multiyear surveys of desert areas by side-looking radars (SLR) of “Cosmos-1500” and “Sich-1” satellites, synthetic aperture radars (SAR) of ERS-1, ERS-2 and Envisat-1, aimed at identifying the radio waves scattering features manifested in radar studies of aeolian sand and dust transportation processes in desert regions, which can be used for remote determining the parameters of transportation. It was proposed to explain the mechanism of the effect of a highly directional intense radio waves backscatter, which manifests itself in areas covered with deep sand at the direction of irradiating the surface towards the general direction of the surface wind in the range of local irradiation angle surface Q » 31¸34°, due to their interaction with consistently oriented ionized air layers bordering on sand ripples structures in the process of forming it with aeolian transportation of sand-dust mixture. Ionization is caused by strong inhomogeneous electric field arising in the aeolian transport process. Results of the study allow to create new remote monitoring methods of processes in desert areas that affect the climate of vast regions of the Earth.

62-67

Authors: N. N. Beletskii, S. A. Borysenko, N. I. Gvozdev

The defect photonic crystals bordering on the solid-state plasma-like media are worthy of special attention. These structures are of interest due to the occurrence of the plasma and defective waves which can interact resonantly with each other. The effect of resonance interaction of different types of electromagnetic waves in defective photonic crystals is not adequately investigated. In this paper, the resonance interaction of plasma and defective TM-electromagnetic waves in a one-dimensional defect dielectric photonic crystal, bordering on the solid-state plasma-like medium, is studied on the basis of the numerical solution of the dispersion equation. The dispersive and energy properties of plasma and defective waves are investigated in accordance with the dielectric constant of the crystal lattice of the solid-state plasma-like medium. It is found that the resonance interaction of plasma and defective waves depends strongly on the type of solid-state plasma-like media. It is established that the effect of resonance interaction between the plasma and the defective waves takes place when the defective photonic crystal borders on the semiconductor plasma. It is shown that the resonance interaction of plasma and defective waves disappears in the case when the defective photonic crystal borders on metal. The results of the study extend significantly our knowledge about the nature of the resonance interaction of plasma and defective waves in defect photonic crystals. The obtained results can be used in developing new devices of microelectronics and photonics.

81-84

Authors: R. I. Bilous, S. P. Martynyuk, A. P. Motornenko, I. G. Skuratovskiy

The resonance structures serve as the basis for many electronic devices. Therefore the creation of the effective tunable resonator is the actual and important problem. Using of the waveguide-dielectric resonator insures opportunity for the mechanical frequency tuning over a wide range but at the same time the Q-factor is changed. The last investigations suggested that the decrease of the eigen Q-factor of the tuning waveguide-dielectric resonator in the section of the circular cut-off waveguide can be decreased by using the resonance short-circuit plunger calculated on the given frequency. The investigations have been conducted for the 3-cm waveband. This paper is devoted to investigation of the possibility to increase Q-factor of the resonator of the waveguide-dielectric type in the millimeter band where influence of the contact imperfection between the plunger and waveguide walls is essential. As a result of the conducted investigations the Q-factor more than 2 000 in over the band of the tuning frequency was obtained for the resonator made of the section of the circuit cut-off waveguide with the Teflon dielectric in the 8-mm waveband.

94-98

Authors: Yu. A. Nestryzhenko

The laser emission polarization and control of its spectrum by means of low-loss prisms is a problem of considerable importance which has been addressed in a great number of research papers. The known polarizers, especially straight view prisms, are characterized by certain disadvantages arising from losses of light energy and/or a need for additional reflecting coatings. These are not always acceptable for laser application, and the problem of spectral control may require the use of additional elements in the laser cavity. In this paper a four-facet, straight view spectral polarizing prism is described involving no cemented components for controlling the laser polarization and spectrum. The effect is due to additional total internal reflection surfaces inside the prism. Theoretical calculations have confirmed feasibility of such a prism for relatively simple, e. g. rhomboid configuration, and the possibility of manufacturing the device in a simple way. The prototype embodied has been tested and showed an effective laser polarization and possibility of its spectral control. This prism can greatly simplify the procedures for laser tuning, providing new possibilities for polarizational and spectral control of the laser emission and generation of two orthogonal polarized rays which may be useful for effective frequency conversation in nonlinear crystals.