Evgeniya B. Chernikova

The article presents an approach to the development of ultra-short pulse (USP) protection devices operating in differential and common mode. The results of justification of structural design of devices and selection of diagram models that take into account the modes during simulation are given. Parametric optimisation of cross-sections of 6- and 8-wire structures has been performed. Optimisation was performed according to two criteria: minimisation of the output voltage amplitude for differential and common mode separately and minimisation of the square of the difference between the maximum and minimum time intervals to increase the minimum value of the difference between the per-unit-length delays and, as a consequence, to maximise the duration of the USP, which can be fully decomposed. Simulation results with optimal parameters showed that the attenuation of USP in the studied structures increased on average by a factor of 12 in both modes, compared to the attenuation obtained before optimisation. From the analysis of frequency and time characteristics it is obtained that the 6- conductor structure is optimal for use as protection of power supply circuits, and the 8- conductor structure is optimal for both protection of power supply circuits and signal circuits.

This letter presents the study of a reflection symmetric modal filter (MF) and meander lines (MLs) based on a four-layer printed-circuit board. The design goal is to experimentally investigate reflection symmetric MLs and MF to analyze their characteristics and to comparatively evaluate their effectiveness in protecting electronic equipment from ultrawideband (UWB) interference. The intuition behind this letter lies in leveraging modal distortions to decompose UWB pulses into smaller, less harmful components. A meander routing scheme is employed to increase the differences in mode per-unit-length delays, thereby improving interference attenuation while maintaining a compact design. The novelty of this letter includes the first experimental analysis of time responses for one-turn and two-turn MLs, providing significant insights into their behavior and performance. Experimental results, corroborated by electrodynamic simulations, demonstrate that MLs achieve superior attenuation of UWB pulses compared to MFs of equivalent size. Specifically, meander routing enhances UWB interference suppression of the initial MF by at least 2 times in ${N} _{1}$ , 1.63 times in ${N} _{2}$ , and 1.36 times in ${N} _{5}$ norms. In addition, a novel postprocessing technique is introduced to identify combinational pulses in the time response of the one-turn ML, advancing the understanding of pulse decomposition mechanisms. This method successfully demonstrated the presence of combinational pulses. This letter represents a notable advancement electromagnetic compatibility (EMC) by offering efficient and compact solutions for safeguarding electronic systems against UWB interference.

This article presents reflectionless low-pass filters based on a reflection symmetric structure for suppressing intentional electromagnetic interference (IEMI). The protective structures can attenuate ultra-wideband (UWB) and narrowband (NB) IEMIs, and their potential application is investigated. The frequency and time characteristics of the structures are examined in terms of suppressing IEMI and maintaining signal integrity. Full-wave electrodynamic simulation was performed using the finite element method in the frequency range of 0–10 GHz. To verify the simulation results, prototypes were fabricated, and their S -parameters were measured using a vector network analyzer. The results indicate that the structures have a passband of 1.37 GHz for the modal filter (MF) and 0.8 GHz for the meander line (ML). The value of S ₂₁ for both structures does not exceed −15 dB in the frequency range from 3.5 to 10 GHz. In the full frequency range, S ₁₁ does not exceed −15 dB. The comparative analysis of IEMI suppression using these filters demonstrated that the structures offer advantages in terms of attenuating conducted UWB and NB IEMIs according to the analysis of five standard N -norms. The results indicate that all proposed structures can suppress IEMI with different spectra, but the ML structure showed the best suppression performance. However, this resulted in a reduced bandwidth of the ML. The simulation with data rates normalized to the bandwidth of each filter demonstrated that the MF provides higher signal transmission quality.

An approach to improving the reliability and interference immunity of radio-electronic equipment elements by using modal reservation is considered. Optimization results of three structures with multiple modal reservation on a FSD1020T substrate material with two variants of its thickness and line length of 0.06 m are presented. The studied structures include 3-conductor microstrip lines with asymmetry and symmetry of cross-section and excitation and a 4-conductor structure with side polygons. Optimization was performed using amplitude and time criteria. A model was developed and implemented to account for extreme temperatures when simulating structures with modal reservation on a substrate made of FSD1020T material with thermal conductivity parameters λ=0.68W/m*K, relative permittivity εr=10.2±0.05 and loss angle tangent tgδ=0.003 at a frequency of 10 GHz. An analysis of the characteristics of structures with multiple modal reservation and optimized parameters under extreme temperatures was conducted. It is shown that the maximum output amplitude and time intervals between decomposition pulses remain stable with temperature variations.

The article presents the study of a reflection symmetric modal filter (MF) and meander lines (ML) based on a four-layer printed circuit board (PCB). Their prototypes were made, and the transmission coefficients were measured in the frequency range from 10 MHz to 10 GHz. At the output of the structure, the response to an ultra-wideband (UWB) pulse was analyzed. The results of post-processing showed four decomposed pulses at the output of the MF and the ML with two-turns, and six decomposed pulses in the ML with one-turn, which is in complete agreement with the modal theory and analytical models. The N-norms were used to characterize the output voltage waveforms. Both MLs demonstrated better attenuation of the UWB pulse than MFs of the same PCB size. More specifically, the value of N1 decreases by at least 2 times, N2 by at least 1.6 times, and N5 by at least 1.36 times. The values of N3 and N4 remained unchanged. The post-processing method for detecting combinational pulses in the time responses of ML is presented.

The paper presents the results of theoretical justification of the appearance of combinational pulses in the time responses of coupled transmission lines with inhomogeneous dielectric filling. Combinational pulses are of interest because their arrival times do not correspond to the per-unit-length delays of the modes propagating in the lines, but consist of their combinations. They appear because of the asymmetry of the line cross section or boundary conditions. In this study, we formulated analytical expressions for calculating time responses that include combinational pulses, which extends the theory of transmission lines and the development of protection devices based on modal decomposition of pulses. Additionally, we optimized asymmetric structures according to amplitude and time criteria and considering combinational pulses to increase the attenuation of interfering UWB-pulses. We also designed layouts of asymmetric transmission lines with broad-side and edge couplings and investigated them experimentally. The time responses obtained by electrodynamic simulations and measurements confirm the appearance of combinational pulses, which has previously been shown only by quasi-static lossless simulations.

Transmission lines are significant elements and play an important role in determining the performance, reliability and functionality of radio electronics. A number of factors appearing in the use of transmission lines can lead to problems in the field of electromagnetic compatibility. One such factor is the appearance of asymmetry due to inhomogeneities, PCB manufacturing errors, dense tracing, mismatch, etc. The paper considers the effect of asymmetry on the characteristics of transmission lines with inhomogeneous dielectric filling. It is found that asymmetry of cross section and/or boundary conditions leads to the appearance of combinational pulses. Combination pulses are of interest because their arrival times do not correspond to the per-unit-length delays of the modes propagating in the transmission lines, but consist of their combinations. Their level may be comparable to the level of information signals, which may result in distortion or loss of useful information. Meanwhile, asymmetry and the resulting combinational pulses represent a new resource for improving the performance of devices based on transmission lines, which can be used to protect radio electronics from electromagnetic interference of picosecond and nanosecond duration. For the first time the optimization of parameters taking into account combinational pulses is carried out on the example of three diagrams of symmetric multiconductor transmission lines with asymmetry of termination loads: reflection symmetric and with a reference conductor in the form of side polygons. Using the genetic algorithm, the optimal parameters are obtained, which allow to reduce the value of the maximum amplitude by 1.5 times, as well as the parameters allowing to increase in 2 times the minimum value of the time interval between the decomposition pulses, on which depends the possibility of complete decomposition of the interference pulse, compared to the value obtained in the initial diagram with optimized parameters, where there are no combinational pulses at the same device dimensions. The optimization results demonstrate the efficiency of using the resource of combinational pulses to improve protective structures based on transmission lines with inhomogeneous dielectric filling.

Correct and uninterrupted operation of on-board radio-electronic equipment (REE) operating in extreme space conditions is an important requirement in spacecraft (SC) development and operation, since its violation can cause irreparable damage. Ensuring interference immunity of power supply bus (PSB) of on-board REE of SC. When designing the PSB, the task of ensuring the integrity of the power supply was solved by developing a protection device against conductive interference, including protection against ultra-short pulses (USP). The duration of such interference is in the nanosecond and subnanosecond range. Due to their wide range, such interference overcomes traditional means of protection. To protect against USP, devices called modal filters (MF) have been proposed. MFs are designed to be integrated into PSBs and provide effective protection against USP. Meanwhile, in order to obtain a complex protection effect of a spacecraft against radiated and conductive large-amplitude USP, a joint use of MF and an electromagnetic interference (EMI) filter on elements with concentrated parameters is proposed. For the first time, recommendations on step-by-step development of an PSB protection device against USP, which is a hybrid consisting of MF and EMI-filter, are presented. Experimental studies have shown that such a hybrid attenuates common and differential interference in the frequency range up to 5 GHz by 5.81 and 11.9 times, respectively. In addition, the device is small and lightweight, which is important for space applications.

The study considers the problem of ensuring electromagnetic compatibility of EMI‐based functional destruction means with other radioelectronic equipment as part of a complex for countering unmanned aerial vehicles. To solve this problem, it is proposed to create a methodology that combines a set of diverse approaches and methods. This study focuses on the use of hollow and thin passive conductors, the use of a magnetodielectric in a reflection symmetric modal filter, the use of reflection symmetric structures for decomposing the train of ultrashort pulses (USP), and the use of a meander line as a protective means against USPs. The main results that are expected to be obtained using the proposed approaches and methods are outlined.

This work is devoted to the research of new asymmetry effects in symmetric protective structures with triple modal reservation. We analyzed the structures with different cross-sectional locations of the reference conductor: in the center (unshielded structure), around (shielded structure), at the top and bottom (multilayer printed circuit board), and in the form of side polygons (double-sided printed circuit board). First, a preliminary quasi-static simulation was performed in the range of parameters. It was revealed that in all structures, except for the shielded one (in the form of a cable), the deviations of the output voltage amplitude, bandwidth, and frequency of the first resonance were insignificant, whereas in the shielded structure there were significant deviations in the time and frequency responses. The attenuation of the output voltage in relation to the input for each structure was also estimated. In addition, we performed a parametric optimization of the structures under consideration using a heuristic search, which made it possible to improve their characteristics. Finally, the switching order between the conductors in these structures with the original and optimized parameter sets was investigated in detail. The optimal conductor switching order in the case of a component failure was determined, and the best (according to protective characteristics) parameter configuration for each structure was found.