卷 70, 编号 5 (2025)

Expressions for all frequency characteristics of the input impedance of an idealized passive element of complex fractional order (IPE CFO), i.e. an ideal complex fractal element (ICFE), are obtained. The frequency characteristics of the IPE CFO are presented. The frequency characteristics of the last events of the IPE CFO are considered: elements with a constant phase, with a constant amplitude, and elements with a linear phase. The synthesis criteria for all variants of the ICFE are presented.

The interaction of spin waves propagating as directional modes in microwaves based on iron-yttrium garnet films has been examined. The configuration consists of three microwaves arranged in parallel, with air gaps separating them, allowing for the coupling between them. The source of this coupling is attributed to the long-range dynamic sagging (dipole) field of the precessing magnetization vector. A methodology is put forward to regulate the properties of this coupling by modulating the angle of the static magnetization with respect to the principal axes of the geometry. Micromagnetic modeling was employed to demonstrate the sub-magnetization angle-controlled propagation of spin waves along lateral microwaves. As a consequence of micromagnetic modeling, spin wave propagation spectra were obtained. The subsequent analysis of these spectra revealed that lateral microwaves can function as functional elements in planar magnonic networks, serving as directional taps, spin wave multiplexers, or microwave power dividers. Furthermore, the study demonstrated the capability to control spin wave routing between the microwaves («magnetic channels») through the modulation of the external magnetic field angle.

Linear antenna array with the array element radiation pattern close to sector shape was considered. The array consists of beam-forming network and radiating array of horns. The beam-forming network includes block of coupled dual polarized EBG waveguides and block of phase shifters in form of waveguide sections. Electromagnetic simulation and optimization of the device were targeted to form sector shape radiation pattern in the radiating array plane. The study included three stages. Investigation of eigen modes of an infinite system of infinite coupled dual polarized waveguides was performed at the first stage. Coupling coefficients for waves with two orthogonal polarizations were calculated. At the second stage the beam-forming network was considered as a microwave multi-port junction and its S-matrix was obtained. Simulation of the beam-forming network combined with the horn array was performed at the third stage. It is shown that the investigated array provides the formation of radiation patterns close to sector patterns for waves of two orthogonal linear polarizations in the frequency band up to 10% in the centimeter wavelength range.

The article considers the bremsstrahlung and gyromagnetic radiation of an electron in the field of an inhomogeneous electromagnetic wave in the presence of an external magnetic field. It is shown that when the external magnetic field is perpendicular to the electric field of an inhomogeneous electromagnetic wave, the power of gyromagnetic radiation always exceeds the braking power. It is established that in the case when the external magnetic field is parallel to the electric field of an inhomogeneous wave, there is a threshold field value at which the power of gyromagnetic radiation exceeds the power of bremsstrahlung. It is established that when an electron moves in an inhomogeneous electromagnetic wave, the effect of suppression of the carrier frequency in the electron radiation spectrum can be realized.

The paper discusses hardware implementation algorithms for widely used half-band filters (HBF), such as the Coefficient Quantization Algorithm (CQA), the Multiple Constant Multiplication (MCM) algorithm, and their combination, CQA+MCM. The use of the CQA algorithm reduces the number of multipliers in the HBF filter structure. The MCM algorithm converts multipliers into a set of adders and bit shifts. Combining both algorithms allows for replacing all multipliers with a set of adders and bit shifts. A resource analysis was carried out for hardware implementations of 30th- and 94th-order HBF filters. It was found that the CQA algorithm reduces the number of multipliers by 37 % and 74 %, respectively. The MCM algorithm completely eliminates multipliers from the filter design, but the number of adders increases by 3x and 2.6x, respectively. A comparison with existing methods showed that the time required to compute the coefficients of the optimized filter using the proposed algorithms is only a few seconds, whereas most other methods take significantly longer (up to a full day). It was shown that the difference in the required resources does not exceed 10 %.

The possibility of excitation of precession of the magnetization equilibrium position under conditions of periodic modulation of the submagnetizing field excluding the interfering effect of the domain structure is considered. It is established that for the realization of the precession of the equilibrium position the duration of the period of the alternating field should be such that the domain structure has not had time to develop, and the precession of the equilibrium position has acquired a sufficient amplitude. It is shown that under these conditions the magnetization fluctuations are alternating periods of simple precession and equilibrium precession. A precession portrait, which has the form of two concentric rings, and a magnetization oscillation spectrum containing high-frequency and low-frequency lines are constructed. Possible practical applications of the described phenomena are given.

In modern monitoring and control system devices, when designing analog network filters (ARF), the task is to ensure the operation of the filter taking into account the instability of the network noise frequency, the influence of the external environment, the technological variation in the parameters of the elements and their changes during aging. As a result of the analysis carried out using the Micro-Cap circuit simulation program, it is shown that for the most frequently used second-order ARFs, with a 1 % change in the parameters of their transfer function, it is possible to guarantee line harmonic suppression of no more than –20 dB. On the other hand, when taking into account the change in the line interference frequency by 1 %, the filter’s barrier functions are also significantly weakened. It was found that the effect of a change in the line interference frequency can be reduced by expanding the interference suppression band with a decrease in the quality factor of the second-order ARF. At the same time, the ARF barrier characteristics, taking into account the circuit reliability, can be significantly improved by increasing the filter order.