Radio physics and electronics

3-10

Authors: S.V. Nedukh

Subject and purpose. In this paper, a technique of determining the elements of the high-frequency susceptibility tensor for a magnetic nanostructure under the conditions of simultaneous applying of external DC and high-frequency AC magnetic fields is proposed. Methods and methodology. During the research, a numerical solution of the Landau–Lifshitz–Hilbert equations was used with help of the mumax3 micromagnetic simulation package. The advantage of this package is the use of discrete computer video card resources to speed up the solution of equations. Results. As an example, the form of the frequency dispersion of the components of the magnetic susceptibility tensor under conditions of resonant excitation of the magnetization precession for a single nano-sized permalloy disk 500 and 3000 nm in diameter using the micromagnetic simulation package was obtained. Conclusions. The demonstrated approach makes possible to use the results of micromagnetic modeling for further tasks of electromagnetic properties modeling of promising planar microwave metamaterials based on nanoscale elements from a magnet.

20-29

Authors: Yu.V. Gorishnya

Subject and Purpose. Tweek-atmospherics (night-time low-frequency atmospherics), along with radio transmission by VLF radio stations, are used to study the lower ionosphere. The predictions of the available analytical theory regarding the polarization of such atmospherics and the previously accumulated experimental material describe the left elliptical polarization as a characteristic feature of the tweek-atmospherics in their tail section. The horizontal geomagnetic field’s component in reflection layer of the lower ionosphere should lead, within the theory framework, to non-reciprocity of the “east–west” and “west – east” propagation of tweeks. The study aim was to determine the polarization of tweek-atmospherics using three-component records and to statistically evaluate the null hypothesis regarding to two polarization parameters of tweek-atmospherics. Methods and Methodology. By the ensemble of experimental tweek-atmospheric records of about 300 examples, that is large enough for statistical processing, the polarization was studied along the atmospherics’ waveforms. Results. For the first (fundamental) harmonic, two characteristics of the polarization of the tweek-atmospherics (the polarization ratio and the phase difference) were calculated and analyzed, depending on the parameter identical to an incidence angle. The difference in the polarization ratio values has found between tweek-atmospherics with near-equatorial paths and atmospherics outside the geomagnetic equator area, where the condition of quasi-longitudinal wave propagation along the geomagnetic field is satisfied. Conclusions. Study has shown that the non-reciprocity of the propagation of tweek-atmospherics in the “east–west” and “west–east” directions regarding the geomagnetic field is observed as statistically significant differences in the phase difference at an incidence angle about 40...60˚ that correspond to an ending of head area of atmospheric waveforms.

35-45

Authors: R.E. Pashchenko, V.K. Ivanov, D.O. Tsyupak, U.V. Levadniy

Subject and purpose. The frequency-temporal analysis signals of Doppler radar are in-process conducted multirotor drone. The wide use multirotor drone the results in the necessity of arrangement their flights and control after their use. The basic structural feature of such drone is a presence of rotors which provide their motion, the number of which can change depending on a construction. Methods and methodology. The method experimental researches of the revolved rotors of drone are offered with the use of Doppler radar. Terms and composition of the instrumentation-informative system, in-use during the leadthrough of experiment are described. Results. It is set as a result of the conducted analysis, that with the increase pulsatance of rotation rotor the period of Doppler signal (DS) diminishes (frequency rises), however fixed frequency DS less than pulsatance of rotation, set from a control of drone stand. Thus, than anymore frequency of rotation, the more difference of these frequencies. The features of structure (forms) DS and their spectrums which are complicated at the increase frequency of rotation rotor and their amount are exposed. The features of DS are investigational at different direction of rotation rotors (in one side or in different) at similar their geometrical location. Influence of direction of rotation is thus rotined on the form of temporal realization of DS and their spectrums. Conclusion. The exposed differences in form Doppler signals can be in future utillized for recognition type of drone, and also at the construction models of Doppler signals reflected from drone.

53-62

Authors: V.A. Zolotarev

Subject and purpose. The article describes a new S-band transmit/receive module (TRM). The purpose of the work is to describe characteristics of the module, as well as the main technical and technological solutions introduced. Methods and methodology. In the design of the TRM, numerical methods for simulation microstrip lines and microwave devices were used, and the verification of the proposed technical and technological solutions was carried out experimentally. The Reduction of the cost of production of TRM, as well as the availability of the components were one of the main criteria for choosing the appropriate solutions. Results. The paper describes results of the developing of a S-band transmit/receive module (TRM) with the output power of 50 W intended for the use in active phased array radars. Described solutions that have allowed to reduce the cost of such module, to simplify its production when reaching the characteristics attractive to consumers. The module is developed by using microwave monolithic integrated circuits (MMICs) which are widespread used in 3G, 4G communication systems. The module components are placed on a common printed circuit board (PCB) with a FR-4 substrate. The receiving path provides 36 dB gain with the noise figure of 1.4 dB in the 2.8-3.2 GHz frequency band. Separate 6-bit attenuators and phase shifter are used to control the amplification and the phase shift. The introduced protection systems allow a safe operation of the module with any loads at the antenna port. Conclusions. This paper presents a new S-band TRM, which is based on MMICs widely are used in communication systems. The using of these electronic components, as well as modern powerful gallium-nitride (GaN) components and inexpensive composite materials as the substrate for the PCB, has made it possible to improve the efficiency and reduce the cost of TRM in comparison with existing analogues. High output power, low noise of the receiver and the high isolation of the receiving and transmitting channels in the proposed TRM make it promising for use in modern active phased array radars.