ABSTRACT. The publication, based on the generalization of the processes of detection and tracking of moving objects, shows the possibility of a single methodological approach for the formation of requirements for integrated radar systems for monitoring the surrounding space for monitoring moving objects, regardless of the type of radar sensors used in it, which are called systems for remote monitoring of the environment space in relation to moving objects. This approach provides an isomorphic (analogous) attitude to various processes characteristic of such systems, the use of the same methods for their evaluation, analysis, synthesis and formation of requirements for them, including in the case of a hybrid composition of their sensory part. A methodological scheme for the formation of requirements for the military system of remote monitoring of the surrounding space for moving objects is proposed, subject to financial restrictions on the construction (modernization) of the system, the implementation of which allows to streamline this process on a scientific basis. The result is a set of expected defining characteristics of a specific system, approved by the military management body as the requirements of the appropriate level for this system.

ABSTRACT. Effects of millimetre wave (MMW) radiation in biological objects have been studied for the last several decades. The volume of research on the topic is proportional to the number of new methods and techniques in biological sciences capable of picking up and characterising the MMW-triggered changes in the functionality of the biological object. Yet, regardless of the characterizing technique employed, there is always a question of comparison of MMW-related heating and equivalent conductive heating effect in the sample. Moreover, for a number of reasons related to the complexity of fresh tissue's natural organization and technical imperfections of available today's temperature sensors, the measurement of MMW-associated heating of fresh tissue could be challenging or unreliable. Here, we test the reliability and applicability of two commercially available fluorescent dyes – Rhodamine B and Rhodamine 6G – as a temperature reporter in fresh nervous tissue exposed to intense MMW radiation (100 mW). Results demonstrate the advantages and disadvantages of either dye, their performance, and some practical aspects of usage.

ABSTRACT. This paper presents a practical application of an opportunistic technique for the estimation of rainfall intensity and accumulated precipitation. The proposed technique is based upon signal strength measurements made by commercial-grade interactive satellite terminals. By applying some processing, the rain-induced attenuation on the microwave downlink from the satellite is first evaluated; then the rain attenuation is eventually mapped into a rainfall rate estimate via a tropospheric model. This methodology has been applied to a test area of 30x30 km2 around the city of Dortmund (North Rhine-Westphalia, upper basin of Ermscher river), for the heavy rain event that devastated western Germany in July, 2021. A rainfall map on this area is obtained from a set of satellite terminal deployed in the region, and successfully compared with a map obtained with a conventional weather radar.

ABSTRACT. In this paper the approach to detect atmospheric turbulence using the polarization feature of reflected from liquid hydrometeors signal is analized. The information about presence of turbulence is retrieved from the character of the variation of low frequency component of reflected from liquid hydrometeor radiosignal. The algorithm of turbulence detection is developed as decision of the problem of presence of turbulence of different intensity against the alternatives. The next step of the algorithm is approach to make aircraft dependent turbulence intensity classification and the algorithm of turbulence detection and classification is proposed.

ABSTRACT. This paper considers generalized coherent-polarimetric method of retrieving information about remote objects using electromagnetic waves. Both active and passive electronic systems as well as different objects under observation, operating frequency bands, and physical meaning (interpretation) of the frequency as spectral argument can be used. As an example, retrieving information about turbulence using microwave weather radar is considered.

ABSTRACT. The dispersion properties of electromagnetic eigenmodes in a semiconductor nanotube filled by a nonmagnetic dielectric and placed in a coaxial DC magnetic field have been studied theoretically. A new quantum electrodynamical phenomenon has been predicted. An increase of the twodimensional electron density in the nanotube is shown to lead to the appearance of more and more new branches in the eigenmodes spectrum. It has been demonstrated that the number of branches monotonously increases when increasing the twodimensional electron density and experiences the Aharonov- Bohm oscillations with growth of the number of magnetic flux quanta through the nanotube.

ABSTRACT. The excitation theory of electromagnetic waves in a cylindrical magnetoplasma solid-state waveguide when a magnetized tubular electron beam blows around it is developed. It is shown that the eigen hybrid bulk-surface or surface electromagnetic waves of helicon origin are excited in the waveguide when the conditions of a quasi-stationary electromagnetic field are satisfied. Their excitation is carried out by the beam space-charge field with matching of the longitudinal components of electric field. It is noted that helicons and waves of their nature are formed in a conducting plasma medium in the assistance of an external magnetic field. It is shown that the instability of coupled waves occurs in the electrodynamic system due to the Vavilov–Cherenkov effect.

ABSTRACT. Waveguides with additional layers between hollow core and periodic binary and ternary structure are considered. On the base of dispersion equation solutions dispersion diagrams are calculated. Spatial field distributions are built for different additional layers permittivity values. It is shown that waveguide with ternary cladding has wider possibility for tuning than binary ones. Permittivity changing makes possible to almost double times increasing of the field amplitude in the central part of the channel. This feature can be useful for interaction with sheet electron beams.

ABSTRACT. The paper analyzes the dissipative properties of microstrip (planar) whispering gallery mode (WGM) resonators by comparing the Q-factors of resonators based on both HTS and normal metal films. The analysis was performed in the frequency range from 1.5 GHz to 40 GHz. By using numerical simulation of partial Q-factors it is shown that the value of the total (eigen) Q-factor at a temperature of 77 K for the microstrip WGM YBa2Cu3O7- - based resonator exceeds the Q-factor value obtained for the similar copper-based resonator in the entire frequency range under study. This superiority is about 2 orders of magnitude at 1.5 GHz and about 5 times at 40 GHz.

ABSTRACT. The paper analyzes the oscillation spectrum of a hemispherical open resonator (OR). The first highest axially asymmetric type of TEM10q oscillations is excited in the resonator with the help of two aperture coupling elements located symmetrically with respect to the resonator axis. Each coupling element is a pyramidal horn with an aperture of 6.9×9.6 mm and a length of 85 mm. The connection of the input waveguides with a cross section of 3.6 × 1.8 mm with the resonator is controlled using one-dimensional E-polarized diffraction gratings, which are located on the surface of a flat mirror. A grating with a period of 0.6 mm and a lamella thickness of 0.02 mm was used in the experiment. It is shown that the excitation efficiency of the TEM10q mode in a hemispherical OR using two aperture coupling elements is 0.816. The oscillation spectra of the same resonator excited by slot and aperture coupling elements are compared. It has been established that with the aperture method of excitation, a significant rarefaction of the oscillation spectrum of the resonator occurs.

ABSTRACT. In this paper the behavior of coaxial filter filled with carbonyl iron micropowder was studied. Amplitude-frequency characteristics (AFC) and phase-frequency characteristics (PFC) were obtained. Using the non-resonant technique value of refractive index was measured. Moreover, with the same technique dependence of refractive index on the magnetic field was studied. It is discovered that such a filter has hysteresis losses. Furthermore, varying the amplitude of the magnetic field one can change AFC of the filter (i.e. cut off frequency).

ABSTRACT. Tweek-atmospherics (tweeks), along with radio transmission by VLF radio stations, are used to study the lower ionosphere. The limits for using the new single-position method for determining of electron density in the lower ionosphere by results of analysis of multimodal tweek-atmospherics is studied upon the experimental records. The database accumulated at the Ukrainian Antarctic Station "Akademik Vernadsky" in 2019 has been used by clustering sources of tweeks. It is shown that the propagation West – East non-reciprocity results in the least attenuation for tweeks arriving from the geomagnetic east. In non-equatorial regions the method discussed can be used up to 10 Mm from receiving point for eastern tweeks and no more than 5 Mm for tweeks from western sector, and for tweeks with other propagation directions these limits lay at roughly 7 Mm from receiving station.

ABSTRACT. We present the results of our new study of the torsion-rotation spectrum of the acetamide molecule, CH3CONH2. Despite the fact that acetamide was found to be quite abundant in the interstellar medium its rotation spectrum was studied only up to Jmax = 20 so far. The aim of the present study was to extend the quantum number range involved in the analysis (thus improving the quality of predictions for higher excited rotational states) as well as the frequency range coverage. The new measurements were carried out from the millimeter wave range (starting at 34.5 GHz) to the sub-millimeter wave range (up to 645 GHz) using spectrometers in the Kharkiv and Köln laboratories. Our preliminary fits of the vt = 0, 1, 2 torsional states of acetamide with Jmax = 62 revealed some perturbations which we attribute to distortions caused by the NH2 wagging state at ~259 cm−1 (that propagate down to low-lying torsional states via intertorsional interactions). Extension of our assignments to the third excited torsional state of acetamide is a preparatory step toward explicitly accounting for interactions with the NH2 wagging state of acetamide. So far 421 A-type and 263 E-type rotational transitions up to J = 32 belonging to the third excited torsional state of acetamide were assigned and added to the analysis. A joint vt = 0, 1, 2, 3 dataset involving 8240 rotational transitions was fit using the rho axis method giving the weighted root mean square deviation of 2.8 for a Hamiltonian model that includes 114 parameters.

ABSTRACT. The experimental study and numerical simulation of the strong photon-magnon coupling was carried out for the planar waveguide with the defect, which was used as a planar resonator. The experimental spatial distribution of the magnetic component intensity of the electromagnetic field indicates its considerable increase in the defect due to the novel shape of the defect. The obtained under ferromagnetic resonance conditions transmission coefficient spectra have shown that the maximal value of spin-number-normalized photon-magnon coupling strength gN has reached 0.89 Hz at the frequency of 6.4 GHz. The optimal size of the YIG film that filled the defect had been established.

ABSTRACT. We present a project of a new DDS-based multi-functional spectrometer and the results of its partial implementation. The proposed instrument may be rather quickly transformed from an absorption spectrometer to an emission one. Multi-functionality of proposed solution allows one to benefit from the strong features of different spectroscopic techniques depending on the goals of performed spectroscopic study. The emission spectroscopy techniques may be applied to reach the highest sensitivity or allow studying of non-stationary objects with a segmented chirped-pulse mode. The absorption spectroscopy techniques may be applied to reach the highest resolution and accuracy via Lamb-dip measurements or allow traditional studying of molecular spectra with Doppler-limited resolution.

ABSTRACT. It was numerically shown that for a system of a spiral plasmon resonator with magnetic film, a large value of photon-magnon coupling strength for the mode with a field structure in the form of an electric dipole is observed. It is explained by the fact that the magnet filling factor by the magnetic field reaches large values for this mode, since the field decreases rapidly along the normal to the resonator plane.

ABSTRACT. Radio recombination lines (RRLs) have proven themselves as a convenient tool for interstellar medium (ISM) diagnostics. Their observations at low frequencies, particularly at decameter waves, provide the precise and independent method for determining of physical parameters of cold, partially ionized cosmic plasma. In this paper results of highly sensitive decameter carbon RRLs observations carried out at Ukrainian UTR-2 radio telescope for ISM regions lying toward Cygnus A and Perseus A radio galaxies have been described. For the first time it was become possible to detect decameter carbon RRLs toward Cygnus A. The ISM studying by means of decameter RRLs in directions towards bright extragalactic sources is an important branch of modern astrophysics and the using of Ukrainian radio telescopes for these purposes is very promising.

ABSTRACT. An algorithm for optimal signal processing in the radar, measuring three components of the full helicopter flight speed vector, has been synthesized. Several partial problems have been solved for this. In particular, the equation of the distance between the radar antenna and the underlying surface has been found, considering that the helicopter can occupy any position in space relative to the underlying surface. In the solved problem, the antenna radiation pattern is rigidly fixed relative to the helicopter building axis. Unlike the traditional approach, which consists of measuring the components of the velocity vector along the 0x and 0y coordinates by the Doppler frequency shift, the range "migration" information parameter within the irradiated section of the underlying surface is used. As a probing signal, the feasibility of using a signal with linear frequency modulation is substantiated. In contrast to the conventional approach to synthesizing speed determination problems, it is proposed to present the received signal as a superposition of signals reflected by the area irradiated by the antenna's directional pattern. It is shown that it is enough to form three independent beams that are correspond to three independent channels of measuring the law of the range change to solve the problem. Based on the synthesized signal processing algorithm, a structural diagram of the radar has been developed. The results of radar modeling confirm the effectiveness of the results presented in the report.

ABSTRACT. The present study investigates electromagnetic diffraction by a pulse from 2-D dielectric objects. A narrow Gaussian beam in the time domain is employed as the incident electromagnetic waves with a large period. The reflected field from the scatterer differs from the object dimension, orientation, and relative permittivity. Therefore, the object location, orientation, and electrical and physical properties of the object can be deduced from the difference in the reflected field characteristics in the time domain. The Method

ABSTRACT. On the basis of formal systems the problem of creating knowledge models for the task of recognition of radio-emitting objects and their states in terms of a priori uncertainty is considered. As a formal system the first order predicate calculus extended by aletic modal logic operators is used. The mechanism of logical inference is developed using a modified method of resolutions. The examples of construction of knowledge models, implemented with the use of expert system are given and experimental studies, which confirmed their effectiveness and high reliability of the results achieved, are carried out

ABSTRACT. In order to create new inconspicuous for contemporary radar detection systems vehicles or to cloak the existing ones some effective instruments for defining the object Radar Cross Section (RCS) are needed. The criterion of truth in this case always is the experimental measurements, but in many cases it is difficult or sometimes impossible to provide its. So, one need reliable and efficient calculation methods to estimate radar detectability of a model of the complex shape object for typical wavelength in radar range. The existing calculation methods assume the scattering field obtaining for each small parts (each facets) of the surface of the investigated model. For radar range the number of such facets can be very significant and the scattered field calculation for all such facets can take a lot of time. On the other hand real radar measurements frequently provides with low accuracy, so the high accuracy in calculations is not needed. It this paper we are going to obtain the approximation formulae for quick estimation of RCS for complex shape object.

ABSTRACT. This paper considered the problem of ensuring the stability of the algorithm for detecting radar signals reflected from a moving target to non-Gaussian clutter. An empirical Bayesian approach for the synthesis of decision-making rules is implemented using an autoregressive disturbance model and develops a robust adaptive algorithm. The effectiveness of the synthesized algorithm under the influence of non-Gaussian interference was determined, and computer simulation was carried out using the Monte Carlo method.

ABSTRACT. Here we reported the effect of the amination of the brominated polyacrylonitrile carbon fibers (PAN CFs) on the efficiency of absorption of electromagnetic radiation studied for the X- and Ka-bands. The fiber modification was carried out by bromination with bromine liquid followed by amination with one of the amines: ethylenediamine (En), sulfolanylethylenediamine (SuEn), diethylamine (Et2N), monoethanolamine (MEA), and piperazine (Py). The amination caused the replacement of attached bromine groups with amino groups. The thermal desorption properties of the prepared PAN CFs were investigated using TGA and TPD MS methods. Thermal desorption of the products of amino groups decomposition from the surface of PAN CFs ranges from 140 to 415 °С with maxima at 240–258 °С depending on the modifying amine and the surface concentration of the amino groups. For the X-band, the type of amine used is not of significant importance, and the value of the absorption for electromagnetic radiation does not exceed −18 dB. In the Ka range, the brominated PAN CFs modified with Py, En, and SuEn reduce the electromagnetic radiation by about −19 dB, −23 dB, and −28 dB, correspondingly. From all the above, it is clear that the brominated PAN CFs modified with amines have a perspective for use as a protective material against the harmful effects of electromagnetic radiation on biological tissues in the Ka-band frequency range. By choice of amine modifier, the absorption magnitude can be regulated when forming a surface protective-and-absorptive layer.

ABSTRACT. We report on the synthesis of the periodic nanostructures of ‘parquet floor’ type on the surface of single-crystal indium phosphide. The structures were formed by electrochemical etching with the subsequent electrochemical deposition. The obtained structure is characterized by a well-ordered displacement of the nanowires in the longitudinal and transverse directions. It was studied that the nanowires consist of porous oxide. A qualitative explanation of the electrochemical processes that occur at the electrolyte/semiconductor boundary during electrochemical treatment is presented. The obtained structures can be applied as photonic crystals and require further studies

ABSTRACT. The interest in the structures like micro circular dielectric cylinders covered by a graphene layer (GCCDMC) is because they can be used for sensing applications. In this case, the knowledge of peculiarities of their resonant regimes is extremely useful. In this paper free oscillations of such structures are studied in the frame of the spectral problem in which complex resonant frequencies and modes field structures are discussed. The H-polar case is discussed. It was shown that complex frequencies can be split in two families, which correspond to the modes of dielectric waveguide perturbed by a graphene cover and modes of so-called plasmon modes which are concentrated in the graphene area. Also spectral problem was analyzed for perfectly conducting (PEC) cylinder. The field structure of the eigen modes is presented.

ABSTRACT. Plane wave scattering by a periodic finite array with graphene patches on a cylindrical surface (CPFGA) is studied. In discussed CPFGA N graphene patches are placed on a dielectric rod (DR) surface in the azimuth direction. To build a problem solution the Method of Moments (MoM) was applied in the spectral domain using Piece Wise Sinusoidal (PWS) basis functions. The cases of N=1,2,3,4 patches are studied. The radar cross section versus frequency is studied for both E- and H- plane wave polarization. The current distributions and far fields at the resonant frequencies are calculated.

ABSTRACT. Nonlinear rf dynamics of composite Abrikosov vortices in two-band superconductors is considered in the framework of the elaborated phenomenological model. The possibility of dissociation of composite Abrikosov vortices with a whole magnetic flux quantum into fractional components under the influence of a rather strong microwave current is argued. The threshold for such kind of dissociation is calculated as a function of the microwave current amplitude and frequency. The possible manifestation of this type of vortex dissociation through the peculiarities of the amplitude dependencies of nonlinear surface resistance at different frequencies is considered.

ABSTRACT. Plane wave scattering by the system, which consists of the perfectly-electric conducting (PEC) zero thickness half-plane and two PEC zero-thickness circular disks is considered. We study only the case when the disks are placed on the one side of the half-plane. The operator method is used. The scattered field is expressed in terms of the superposition of the plane waves with the use of the Fourier integrals with unknown amplitudes. The operator equations for these amplitudes are reduced to the integral equations. Since the scattering operators of the half-plane have singularities, the regularization procedure is performed. The scattered field can be represented as a superposition of the plane wave, cylindrical and spherical waves. The far field of the spherical waves and the total near field is studied.

ABSTRACT. Shielded loops have recently attracted keen interest in the design of Magnetic Resonance Imaging (MRI) detector arrays. To prevent unwanted detuning of array elements, a preamplifier decoupling is used. So far, the decoupling circuit design was based on intuitive approach of minimizing impedance presented to the terminals of the loop. The approach leads to decent but not optimal results. In this paper a systematic analytical method is used to derive the exact condition for maximum decoupling of shielded loops in array. The condition describes precisely what impedance should be presented to the terminals of the loop for best decoupling. It is shown that the method is valid for single- and multi-gap shielded loops with and without integrated reactive components across the gap. The presented results are useful in the design of MRI receive arrays of shielded loop coils with optimal decoupling.

ABSTRACT. Experimental plasma gun testing bench on the basis of the virtual cathode has been presented. A number of plasma characteristics such as discharge voltage, plasma temperature, glow dynamics and others are estimated. The interferometer scheme was developed, successfully installed, and preliminarily tested on the experimental testing bench. Obtained results will be used for electron concentration measurement of plasma in the millimeter wave band.

ABSTRACT. We present the practical application of microwave dielectrometry method for the express monitoring of the proteins hydrolysis reaction course. The method is based on the complex permittivity determination of the reaction mixture at the frequency of 31.82 GHz. The idea of our approach is the measuring of the differences of the wave phase Δφ and amplitude ΔA of the electromagnetic wave passing through the cells of the dielectrometer cavity (when the one cell is filled by the tested solution and another cell is filled by the reference liquid). The dependence of complex permittivity on time is obtained. During the enzymatic protein hydrolysis reaction course, we observe changes of the real and imaginary complex permittivity parts of the measuring reaction mixtures - multicomponent aqueous solutions, such as: IgG with enzyme trypsin, milk with enzyme trypsin. The complex permittivity of the tested solutions is growing with the time of the hydrolysis reaction that can be explained by the increase of the amount of free water in the reaction system. The experimental results showed that the proposed method is effective for the real time reaction monitoring and allows us to use our dielectormetry setup for dynamic control of the proteins hydrolysis reaction.

ABSTRACT. The possibility of overcoming some hardware limitations resulting in low quality of terahertz images is considered. The set of images obtained at different distances from the source of terahertz radiation at frequency 0.1 THz is studied. It is shown that the noise in these images is mixed and has quite high level of spatial correlation. A fully automatic denoising method based on the use of discrete cosine transform with spatially adapted spectrum is proposed. It is shown that despite initially low spatial resolution of terahertz images and intensive noise, the proposed denoising method provides good noise reduction with good preservation of edges and details, which allows to noticeably enhance the quality of these images.

ABSTRACT. Studies have been conducted with the goal of obtaining an estimate of the range of applicability of open-ended biconical microwave resonators for determination of average electron density in low-temperature plasma. It is shown that an open-ended biconical microwave resonators make it possible to measure the electron density plasma over a wider range than cylindrical resonators.

ABSTRACT. Wire media is a class of metamaterials that presents the dense metallic wires array with the length L, wire radius r and lattice period a included into a dielectric host material. It widely used for narrow (at Fabry-Perot resonances) and broadband power transfer, and endoscopy. Nowadays, the imaging is performed at the Fabry-Perot resonances for the subwavelength distance. It is because of the resonant nature of the transfer where is strong binding to the WM sizes. The known investigations shown the mechanism how to carry out the transfer of electromagnetic (EM) waves beyond the structure resonances. However, broadband imaging is still not performed and we are going to fill out this gap by the presented research. The idea is based on the usage each of four adjacent wires as a separate channel with a-by-a dimension. By location of the point sources nearly to the wires’ edges of each channel, the strong near-field interaction arises, the canalization regime becomes suppressed and, as a result, a broadband transfer is supported. On this condition, the transfer of the whole image is performed by an array of parallel guiding channels into which the WM endoscope effectively splits. We have assumed that beyond the resonances of the WM sample these unit cells can operate as independent waveguides enabling the transfer of power by a quasi-TEM wave from point sources located in the middles of some unit cell to the output interface of the WM sample. Therefore, our WM endoscope represents a digital telegraph transferring the image of the matrix of elements in which some elements are bright and others are dark. The information about the location of the bright and dark elements is transmitted to large distances without electric contact with both matrices – that of transmitting (Tx) and that of receiving (Rx) elements. The constructive parameters of the WM L = 400 mm, r = 0.5 mm and a = 10 mm were picked up for the investigations in GHz frequency range from 1 up to 4 GHz (L = ~1.3λ…5.3λ). The length of our dipole sources (9 mm) was small enough to locate them in our unit cell. Thus, the condition of the far-field wireless imaging was respected. For the correct sources arrangement at the input interface, the spatial resolution should be investigated and defined the step 2a of the dipole possible step. It allows the maximal number of pixels in the image R = nm/4, where the EM endoscope comprises n- by-m wires. In accordance with the obtained results for the resolution, we performed the transfer of the image shaped as the letter N at frequencies from 1 to 4 GHz. For a digital representation of the scanned E-field distribution at the output WM’s interface, the received image we applied digital signal post-processing based on a threshold following Otsu's method. The clear digitalized pictures are reached. The suggested WM endoscopes can find the number of applications including even THz and the visible frequency range. Note, that besides the imaging the property of the nearly independent signal transfer in adjacent effective channels excited by different sources can be used for the replacement of microwave and mm-wave arrays of waveguides by a very simple counterpart – WM sample. Moreover, waveguides at microwave and mm-wave arrays are quite narrowband, whereas our WM endoscope can be used for the transfer of many poly-harmonic and broadband signals in the different parts of the same sample.

ABSTRACT. CPI, partnered with Bruker, has been engaged in a long-standing program to develop gyrotrons for Bruker’s commercial dynamic nuclear polarization (DNP) enhanced nuclear magnetic resonance (NMR) spectrometers. The Bruker-CPI development program, started more than 15 years ago, has resulted in a family of robust and reliable continuous wave (cw) high-frequency gyrotrons. The design features and measured performance of the Bruker-CPI gyrotrons at 263, 395, 527, and 593 GHz, all of which have demonstrated over 50 W cw output power in high-quality Gaussian beams, will be described.

ABSTRACT. The synthesis of a single-channel broadband device for receiving and primary processing of radio signals that employs the pulse compression technique is presented given the case where its input signals are received in conditions of their structural-parametric a priori uncertainty. The synthesis was carried out based on the mathematical apparatus of the theory of statistical decisions and on the discrete signal representation in the time-frequency domain. The results of prototyping and experimental studies concerning the receiver that was synthesized in accordance with the structural-functional diagram on the basis of spectrum analyzer with pulse compression technique (SAPCT) are briefly presented. An experiment is described that allowed us to verify the possibilities of obtaining the Fourier transform with regard to the elements of input signals, as well as possibilities of detecting and measuring the frequency-time parameters of these signals. These parameters allow us to figure out the structure and characteristics of input signal bursts.

ABSTRACT. Tuneable Active Filter (TAF) is a microwave system which translates the “perfect” Intermediate Frequency (IF) filter bandwidth to the tune-able RF to notch the interference or to pick up a narrowband signal for a frequency-hoping receiver. TAF is useful in a considerable number of use cases. TAF on market offer a room for miniaturisation hence, we carried out laboratory simulations to address TAF practicalities, to prepare for a follow-on integration. We explain the TAF concept, list (some of) market examples, describe the working principle and provide laboratory simulation examples to address TAF practicalities. We provide the foreseen application's high-level requirements. We demonstrate TAF's successful operation in both X-band (L-band IF filter), V-band (crystal filter IF) clarifying particularities to access for the follow-on miniaturization, such as the signal leakage, the LO leakage, the harmonic suppression. Two built TAF demonstrators might serve for the follow-on work.

ABSTRACT. The results of the development and testing of a microwave scanning radiometer are presented

ABSTRACT. In this paper, it is shown that an aircraft antenna array that uses the Global Navigation Satellite System (GPS) for navigation does not provide spoofing mitigation or suppression in the case when the spoofer is located in the upper and lower hemispheres. we demonstrate the antenna array design that allows us to detect and suppress spoofing from any direction. The antenna array aperture consists of two identical parts. These parts can receive navigation satellite’s signals as well as spoofing from upper and lower hemispheres. Aperture antenna elements are combined in pairs with analog adders. Satellite signals and spoofer (if present) from the output of adders pass sequentially through the analog and digital modules. Signals from digital modules are summed in the adder. In the adder, the weight coefficients are generated. These coefficients are equivalent to the formation of the amplitude-phase distribution on the apertures, at which spoofing suppression is provided. The study of the five-elements antenna array model in MatLab has shown that deep spoofing suppression is provided. Maximum of four spoofers can be placed in any combination in the upper and lower hemispheres. When spoofing suppression, the antenna array radiation pattern is deformed and some of the satellites become inaccessible. The simulation results of the five-elements antenna array are presented in the form of a radiation pattern. The positions of navigation satellites are consistently aligned with the radiation patterns after spoofing suppression from four directions for the lower and upper hemispheres and coordinates of the spoofer.

ABSTRACT. This study proposes a patch antenna design with a narrow angle of four beams to be employed in four remote areas. The antenna is designed to radiate four beams in the 5G frequency range, which can be used for V2X and detect flying objects. The operating frequency range is between 5855MHz and 5925MHz. In the corresponding bandwidth, |the S_11 | value is less than -10 dB.

ABSTRACT. This paper presents a new design method for high attenuation of a lumped element band-stop filter. The designed 960 - 1215 MHz band-stop filter is a structure that passes below 750 MHz and above 1500 MHz and provides an attenuation value below -50dB. This 7th-order modified Chebyshev topology band-stop filter designed with lumped elements has been manipulated to provide a -50 dB attenuation value by manipulating the Q factor values provided by the resonance structures. The synthesis and development processes of the band-stop filter are mentioned respectively. The design was created in the AWR Design Environment and simulated with ideal and vendor components. PCB was designed and implemented using the Altium Design Software. PCB design was manufactured S-parameter measurements of the band-stop filter were taken and recorded.

ABSTRACT. This report presents the results of dual-tunable band-pass filter characteristics measurement. The filter operation is based on the straight-edge ferrite resonator (made from Y-type hexaferrite) symmetrically coupled to the input and output microstrip transmission lines. The filter demonstrated magnetic tunability within 8-12 GHz frequency range by the in-plane bias magnetic field and electric control of the passband center frequency due to current-induced nonlinear magnetoelectric effect. The electric tuning of the center frequency up to –(1150±90) MHz was obtained for the 200 mW of DC electric power applied to the ferrite resonator.

ABSTRACT. We aim to test the influence of the focused ion beam on the magnetic properties of the simple permalloy structures. We showed through simulation and experiment that the switch from an initial state to the single domain happens even for the partly cut elements. The formed trenches' precise parameters and the required minimal dose are yet to be determined.

ABSTRACT. Abstract—Modeling results of planar 2D/3D semiconductor heterostructure based on GaN/MoS2 junction are presented. The heterostructure represents a III-nitride based planar diode with length of 1 m. The diode has a GaN n-type channel and MoS2 layer placed at the bottom and connected to anode contact. Doping concentration in the channel is (1–6)•1022m−3. Model of electron exchange between 2D and 3D regions of the diode is proposed. Electron transition between 2D and 3D region of diode is suggested to occur due to polar optical phonon scattering. Monte Carlo simulation of electron transport in device is carried out. Dependences of current density on applied voltage are obtained. Impact of parameters of MoS2 layers on current – voltage characteristic of diodes is discussed.

ABSTRACT. The experimental study of the detection properties of new planar microwave diodes based on gated asymmetrical selectively doped semiconductor AlGaAs/GaAs structures on a polyimide film and a crystal substrate in the millimeter wavelength range (51 GHz – 144 GHz) at temperatures in the range from nitrogen (77 K) to room temperature (300 K) is carried out. Dependences of the voltage sensitivity of microwave diodes on the level of incident power and on frequency of electromagnetic radiation are obtained. The value of voltage sensitivity from 6 V/W to 10 V/W was determined. It is shown that the investigated diode structures retain their characteristics within the specified frequency range without significant deterioration at higher frequencies of the range. At nitrogen temperatures voltage sensitivity increases several times compared to room temperatures. Results of the research indicate the promising applications of these diode structures for sensors in the gigahertz and terahertz frequency bands.

ABSTRACT. The conditions under which the transistor was created are considered. Information about the opening of the p-n transition in the UNITED STATES and the USSR is provided. Biographies of J. Bardeen, W. Shockley, and W Brattain, as well as Ukrainian scientist Vadim Lashkarev, are presented. The reasons why the priority in creating a transistor belongs to American scientists are shown. It emphasized the impossibility of the reaction of Ukrainian scientists to award the Americans with the Nobel Prize and, accordingly, the recognition of the priority in the opening of the transistor by the world scientific community. American scientists worked in Bell Telephone Laboratories, founded in 1925, they were free to choose research, while Ukrainian scientist was repressed, he was ‘‘unreliable’’ and could not leave the country. The discovery of the p-n transition that was made by Russell Shoemaker Ohl in 1939 and the inability to find out about it in Ukraine are analyzed. It is claimed that a similar discovery was made by V. Lashkarev in 1941

ABSTRACT. The multiprobe microwave multimeter frequency properties dependence on the its sensors periodicity is considered in the report. The multimeter is device for incident, passing, reflected power and modulus and phase of load reflection coefficient measurement. The part of multiprobe microwave multimeter is a section with equidistantly mounted sensors. It is a periodic structure. The proposed model of a multiprobe microwave multimeter unit with equidistantly mounted sensors is grounded on the Floquet theorem and continuity condition. Mathematical models for periodic structures and their frequency properties were analyzed. Presence of passing band and forbidden band in the frequency range on the basis of this model was explained.

ABSTRACT. The 2 MW 170 GHz single-frequency coaxial-cavity short-pulse pre-prototype is upgraded to operate also at 204 GHz. Therefore, the quasi-optical output coupler, which is a gyrotron key component, has been modified. Before the newly manufactured quasi-optical output coupler is installed into the gyrotron, a low-power cold measurement for the verification is performed. Therefore, a mode generator is designed and adjusted to excite the relevant operating gyrotron modes, namely the TE34,19 mode at 170 GHz and TE40,23 mode at 204 GHz, with excellent purity and a low counter-rotating amount of < 0.5 % for both modes. The TE40,23 mode is the mode with the highest eigenvalue ever excited in cold tests. After the successful mode excitation, first the fabricated launcher and then the entire quasi-optical output coupler are verified, showing excellent agreement with the simulation.

ABSTRACT. Wave beams with different spatial polarizations have found a variety of practical applications. These beams are used in material processing, high resolution metrology, electron acceleration, spectroscopy and microellipsometry. However, at the moment, there are practically no theoretical or experimental results on the features of propagation and focusing of CW THz radiation. For a theoretical study of the propagation and focusing of THz laser beams excited by the modes of a waveguide quasi-optical resonator, the Rayleigh-Sommerfeld vector theory was applied in the work. Well - known methods of measuring in the THz range were used for experimental study. The obtained results supplement the ideas about the features of the propagation of terahertz laser beams, as well as their sharp and moderate focusing.

ABSTRACT. We report on the recent advances in CMOS-based electronic sources and detectors developed for the THz frequency range. In particular, we present systems operating in the range 200 - 260 GHz exhibiting input power-related signal-to-noise ratio (SNR) exceeding 70 dB in the direct detection regime for one Hz equivalent noise bandwidth. It combines the high-performance detector based on CMOS field-effect-transistors (FET) and a voltage-controlled oscillator (VCO) employing Si or SiGe bipolar transistors provided by the 65 nm CMOS or 130 nm BiCMOS process.