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Wyniki wyszukiwania dla: TRIPLE-BAND%20ANTENNAS
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Miniaturized uniplanar triple-band slot dipole antenna with folded radiator
PublikacjaA miniaturized uniplanar slot dipole for triple-frequency operation is presented. The antenna consists of a folded slot radiator with an increased number of degrees of freedom that allow for efficient size reduction. Rigorous electromagnetic (EM)-driven design optimization is applied in order to achieve the smallest possible size while maintaining acceptable levels of antenna reflection at the required operating frequencies. The...
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Rapid dimension scaling of triple-band antennas by means of inverse surrogate modeling
PublikacjaGeometry scaling of antennas, i.e., finding optimum dimensions of the structure for given operating conditions and material parameters is an important yet challenging problem. In this paper, we discuss fast dimension scaling of triple-band antennas with respect to operating frequencies. We adopt the inverse surrogate modeling approach where the surrogate model is a function of the three operating frequencies of the antenna and...
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Designing a High-sensitivity Microscale Triple-band Biosensor based on Terahertz MTMs to provide a perfect absorber for Non-Melanoma Skin Cancer diagnostic
PublikacjaNon-melanoma skin cancer (NMSC) is among the most prevalent forms of cancer originating in the top layer of the skin, with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) being its primary categories. While both types are highly treatable, the success of treatment hinges on early diagnosis. Early-stage NMSC detection can be achieved through clinical examination, typically involving visual inspection. An alternative,...
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Simulation-driven size-reduction-oriented design of multi-band antennas by means of response features
PublikacjaThis study addresses the problem of explicit size reduction of multi-band antennas by means of simulation-driven optimisation. The principal difficulty of electromagnetic (EM)-based miniaturisation of multi-band antennas is that several resonances have to be controlled independently (both in terms of their frequency allocation and depth) while attempting to reduce physical dimensions of the structure at hand. The design method...
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Expedited Yield Optimization of Narrow- and Multi-Band Antennas Using Performance-Driven Surrogates
PublikacjaUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of antenna systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the antenna characteristics. In the case of narrow- or multi-band antennas, this usually leads to...
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Spurious Modes in Model Order Reduction in Variational Problems in Electromagnetics
PublikacjaIn this work, we address an everlasting issue in 2 model order reduction (MOR) in electromagnetics that has 3 remained unnoticed until now. Contrary to what has been 4 previously done, we identify for the very first time spurious 5 modes in MOR for time-harmonic Maxwell’s equations and 6 propose a methodology to remove their negative influence on the 7 reduced order model (ROM) response. These spurious modes 8 have nonzero resonance...
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Accelerated Re-Design of Antenna Structures Using Sensitivity-Based Inverse Surrogates
PublikacjaThe paper proposes a novel framework for accelerated re-design (dimension scaling) of antenna structures using inverse surrogates. The major contribution of the work is a sensitivity-based model identification procedure, which permits a significant reduction of the number of reference designs required to render the surrogate. Rigorous formulation of the approach is supplemented by its comprehensive numerical validation using a...
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Global EM-Driven Optimization of Multi-Band Antennas Using Knowledge-Based Inverse Response-Feature Surrogates
PublikacjaElectromagnetic simulation tools have been playing an increasing role in the design of contemporary antenna structures. The employment of electromagnetic analysis ensures reliability of evaluating antenna characteristics but also incurs considerable computational expenses whenever massive simulations are involved (e.g., parametric optimization, uncertainty quantification). This high cost is the most serious bottleneck of simulation-driven...
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Tolerance Optimization of Antenna Structures by Means of Response Feature Surrogates
PublikacjaFabrication tolerances and other types of uncertainties, e.g., the lack of precise knowledge of material parameters, have detrimental effects on electrical and field performance of antenna systems. In the case of input characteristics these are particularly noticeable for narrow- and multi-band antennas where deviations of geometry parameters from their nominal values lead to frequency shifts of the operating frequency bands. Improving...
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Triple Helix
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Induction motor bearings diagnostic indicators based on MCSA and normalized triple covariance
PublikacjaInduction motors are one of the most widely used electrical machines. Statistics of bearing failures of induction motors indicate, that they constitute more than 40% of induction motor damage. Therefore, bearing diagnosis is so important for trouble-free work of induction motors. The most common methods of bearing diagnosis are based on vibration signal analysis. The main disadvantage of those methods is the need for physical access...
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EMULACJA ŚRODOWISKA DLA ZASTOSOWANIA PROTOKOŁU IN-BAND NETWORK TELEMETRY
PublikacjaOkreślenie jakości obsługi strumieni pakietów w sieci przełączników wymaga odpowiedniego środowiska badawczego w którym prowadzi się doświadczenia i pomiary wybranych wielkości. Protokół In-band Network Telemetry jest jednym z narzędzi, które można wykorzystać do realizacji tych zadań. W pracy zaproponowano zwirtualizowane środowisko badawcze w którym można emulować sieć przełączników programowalnych w języku P4 wraz z implementacją...
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Smart acoustic band structures
PublikacjaSmart acoustic band structures exhibit very interesting and non-standard physical properties due to the periodic nature of their certain characteristic on different scale levels. They manifest mostly in their frequency spectra as socalled frequency band-gaps or stop-bands, what has a great impact on the behaviour of these structures in relation to the propagation of vibro-acoustic signals that can be transmitted through the structures...
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JOURNAL OF BAND RESEARCH
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Miniaturized Inline Bandpass Filters Based on Triple-Mode Integrated Coaxial-Waveguide Resonators
PublikacjaThis work presents a design technique to implement miniaturized cross-coupled bandpass filters in inline physical configurations based on triple-mode resonators. Triple-mode resonances are obtained by using integrated coaxial-waveguide cavity resonators. They consist of two coaxial conducting posts placed in the sidewalls of a rectangular waveguide cavity. In the proposed triplet, a transmission zero (TZ) can be positioned at any...
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Rola parków naukowo-technologicznych w modelu triple helix na przykładzie parków Polski Wschodniej
PublikacjaCelem artykułu jest omówienie roli parków naukowo-technologicznych w modelu triple helix, zarówno w aspekcie teoretycznym, jak i w oparciu o przeprowadzone badania empiryczne. Autorki zaprezentowały wyniki badańdotyczących powiązań wybranych parkówz pozostałymi grupami aktorów wyróżnionymi w modelu triple helix, ze szczególnym uwzględnieniem instytucji B+R, władz publicznych oraz innych instytucji pośredniczących. Badania przeprowadzono...
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The new concept of product. Cooling band
PublikacjaThe chapter below presents the innovative solution consist in applying the cooling band to help holding the hot object. The solution was found through substitute inputs analysis and brain storm method. The new product was submitted in Polish Patent Office under the No. W.120905.
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Low cost microwave X-band generator
PublikacjaA low cost microwave X-band generator for educational purposes was designed and built. Its simple construction and user's interface makes it suitable for a student laboratory.The generator is based on a single frequency conversion concept. It uses a digitally tunable PLL chip for intermediate frequency generation and an active frequency multiplier for frequency conversion. The generator covers 9,7 - 11 GHz part of the X frequency...
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Design and Implementation of a Dual-band Filtering Wil-kinson Power Divider Using Coupled T-shaped Dual-band Resonators
PublikacjaThe paper introduces a novel structure of a dual-band filtering Wilkinson power divider (WPD). Its essential component is a dual-band bandpass filter (BPF), implemented using coupling lines and two T-shaped resonators. The BPF is incorporated into the divider structure to suppress the unwanted harmonics within the circuit. The latter is achieved owing to a wide stopband of the filter. The deigned dual-band WPD can suppress third...
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Design of a SiC based triple active bridge ceil for a multi-megawatt DC-DC converter
PublikacjaThe paper describes the design methodology of a novel Triple Active Bridge cell used as the building block for modular DC-DC converters. The intended application is for Medium Voltage Direct Current grids, such as the DC collector for offshore wind farms. The latest generation of SiC MOSFET semiconductors is utilized to operate in the medium frequency range while optimizing the efficiency. The dimensioning of the main cell components,...
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Asymmetrical-Slot Antenna with Enhanced Gain for Dual-Band Applications
PublikacjaDual-band operation is an important feature of antennas to be applied in modern communication systems. Although high gain of radiators is rarely of concern in urban areas with densely located broadcasting stations, it becomes crucial for systems operating in more remote environments. In this work, a dual-band antenna with enhanced bandwidth is proposed. The structure consists of a driven element in the form of an asymmetrical radiator/slot...
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Fast geometry scaling of UWB band-notch antennas
PublikacjaImplementation of band-notch capability plays an important role in the design of ultra-wideband (UWB) antennas. At the same time, appropriate sizing of antenna geometry parameters in order to precisely allocate the notch at the required frequency as well as to ensure sufficient reflection level is quite challenging and has to be based—for reliability reasons—on full-wave electromagnetic (EM) simulations of the structure. In this...
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Miniaturized dual‐band branch‐line coupler with enhanced bandwidth
PublikacjaIn this letter, a miniaturized hybrid dual-band branch-line coupler (BLC) with enhanced fractional bandwidths is proposed. Compact size and bandwidth enhancement are obtained using meandered transmission line sections with broken symmetry between cross-coupling branches. The circuit is designed at a low numerical cost using surrogate-assisted techniques. The optimized design features small size of only 0.25λg×0.19λg(28% miniaturization...
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A Critical Reanalysis of Uncontrollable Washboarding Phenomenon in Metal Band Sawing
PublikacjaThe article analyzes the cutting process of hard bars. Investigations conducted in industrial conditions demonstrated the presence of surface errors in the machined workpieces in the form of washboard patterns. The purpose of this study was to analyze the results of cutting on band sawing machines with different band saw blades. The cutting processes were conducted on three different horizontal band sawing machine types. Analyzed...
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Impacts in case of triple unilaterally constrained system
PublikacjaThe this paper focus on the behaviour of a “rigid” body biting into another “rigid” body, with some nonzero relative velocity. In the presently considered case, the introduced collision appears between a selected element of a multibody structure and its reference body being interpreted as the motionless ground. Instead of the classic case, described in a number of dissertations, where a single impacting contact is considered, three...
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Propagation analysis of the point-to-point radio links operating in the band
PublikacjaThe theoretical possibilities of utilizing the EHF-band frequencies for point-to-point short range communications have been discussed. The most important factors that affect propagation attenuation in this band have been briefly described, as well as relevant mathematical formulas that allow for numerical analysis of these phenomena. After that, a research have been carried out in which the authors have analyzed propagation losses...
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Triple Combination of Ascorbate, Menadione and the Inhibition of Peroxiredoxin-1 Produces Synergistic Cytotoxic Effects in Triple-Negative Breast Cancer Cells
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Fast simulation-driven design optimization of UWB band-notch antennas
PublikacjaIn this letter, a simple yet reliable and automated methodology for rapid design optimization of ultra-wideband (UWB) band-notch antennas is presented. Our approach is a two-stage procedure with the first stage focused on the design of the antenna itself, and the secondstage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the band-notch in the desired frequency range. For the...
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Novel Versatile Topologies and Design Optimization of Wide-Bandstop Frequency Selective Surfaces for X-Band, Ku-Band and Millimeter-Wave Applications
PublikacjaNovel designs of frequency selective surface (FSS) are presented for wideband applications in X, Ku and mmWave (millimeter Wave) bands. Two identical metallic layers of FSS are imprinted on both sides of the RO4003 substrate. The geometry parameters are optimized to maximize the bandstop at the specified in-band maximum transmission level of –10 dB; satisfaction of the latter condition is enforced through appropriate formulation...
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Theory of valence-band and core-level photoemission from plutonium dioxide
PublikacjaThe correlated-band theory implemented as a combination of the local-density approximation with the dynamical mean-field theory is applied to PuO2. An insulating electronic structure, consistent with the experimental valence-band photoemission spectra, is obtained. The calculations yield a nonmagnetic ground state that is characterized by a noninteger filling of the plutonium 5f shell. The noninteger filling as well as the satellites...
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Capacity of Surface Production of Band Sawing in Manufacture of Oak Floor Upper Layers
PublikacjaThin lamellae, corresponding to the layer components of structural glued members, i.e., 2-ply or 3-ply glued flooring, can be manufactured in re-sawing operations of kiln-dried wood blocks or in wet technologies, which currently seem to be more common because of the shorter drying time. The re-sawing process in wet technology is conducted on dedicated thin-cutting band sawing machines with stellite-tipped band saws. The goal of...
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High Efficiency Dual-Active-Bridge Converter with Triple-Phase-Shift Control for Battery Charger of Electric Vehicles
PublikacjaAn optimal modulation scheme with triple-phase-shift (TPS) control could increase the efficiency in the entire load range for a dual-active-bridge (DAB) converter under wide output voltage range conditions. Therefore, this study proposes a convergent approach to TPS mode selection, coupled with an optimal modulation scheme, ensuring the circuit’s efficiency over the entire range in the realm of a high-power and high-efficiency...
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Person Tracking in a Ferry Environment Using Ultra-Wide Band Radio Interface
PublikacjaThis article presents research and analysis of effectiveness of tracking moving people in an environment of passenger ferry, using measurements of propagation time of ultra-wide band radio signal (UWB - Ultra-Wide Band). Constructed measurement stand and results of measurements carried out in a real propagation conditions were shortly discussed.
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Role of nitrogen in optical and electrical band gaps of hydrogenated/hydrogen free carbon nitride film
PublikacjaWe report the optical and electrical band gap energy of amorphous hydrogenated carbon nitride (a-HCNx) and carbon nitride (a-CNx) as a function of nitrogen concentration (N/C). The optical band gap of a-HCNx and a-CNx films has been determined by means of Ellipsometry and UV-VIS. Both optical and electrical band gaps increase with elevated nitrogen concentration. Experimentally obtained electrical band gap is compared with the...
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Dual-band antenna with improved gain for WLAN and ISM applications
PublikacjaIn this Letter, a dual-band antenna with an improved gain is proposed. The structure features 9.7 and 10.4 dBi gain within 2.4 GHz to 2.5 GHz and 5 GHz to 6 GHz bands, respectively. This makes it suitable for WLAN and ISM applications. The structure comprises an asymmetrical pair of radiators and slots suspended over a reflector. The antenna is optimised in a two-stage process using a trust-region-based gradient search algorithm....
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Channel Impulse Response Measurements at mmWave Band in Office and Conference Rooms
PublikacjaIn this paper, the measurements of the channel impulse response at mmWave band in office and conference rooms are described. The central frequency is 27 GHz with a bandwidth of 400 MHz. The description of the used measurement stand and considered environments are presented. The initial analysis of the power delay profile, mean delay, and RMS delay spread allows preliminary conclusions to be drawn that there is a significant impact...
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On Design Optimization of Miniaturized Microscrip Dual-Band Rat-Race Coupler with Enhanced Bandwidth
PublikacjaIn the paper, a novel topology of a miniaturized wideband dual-band rat-race coupler has been presented. Small size of the circuit has been obtained by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased in order to secure sufficient circuit flexibility in the context of its design optimization for dual-band operation. Optimum dimensions of...
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Meta-Design and the Triple Learning Organization in Architectural Design Process
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Conjugated control of triple active bridge converter with common HFT
PublikacjaPaper presents synthetic analyses of single input, dual output DC/AC/DC converter with common high frequency transformer. Rise the problem of cross-coupling power flows between secondary terminals, under asymmetrical control operating condition. It also proposes a new approach to converter control, based on conjugated phase shift modulation and defines its limitations. Finally, the developed control technique was verified by simulation...
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Comprehensive dimension scaling of multi-band antennas for operating frequencies and substrate parameters
PublikacjaIn this paper, low-cost and comprehensive redesign of multi-band antennas with respect to the operating frequencies and material parameters of the substrate is presented. Our approach exploits an inverse surrogate model identified based on a set of reference designs optimized at the level of coarse-discretization EM simulations of the antenna at hand. An iterative correction procedure is also implemented to account for the initial...
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Inverse surrogate models for fast geometry scaling of miniaturized dual-band couplers
PublikacjaRe-design of microwave structures for various sets of performance specifications is a challenging task, particularly for compact components where considerable electromagnetic (EM) cross-couplings make the relationships between geometry parameters and the structure responses complex. Here, we address geometry scaling of miniaturized dual-band couplers by means of inverse surrogate modeling. Our approach allows for fast estimation...
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Frequency-dependent coupling model for microwave band-pass filter
PublikacjaThe goal of this work was to create a circuit model which represents frequency-dependent coupling between microwave resonators. Our models are designed for in-line filters. The frequency-dependent coupling enables one to realize a transmission zero which is not possible in classical approach with frequency independent inverters. In addition, the proposed model allows us to observe out-of-band behavior, e.g. spurious resonance....
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Effects of Bromine Doping on the Structural Properties and Band Gap of CH3NH3Pb(I1–xBrx)3 Perovskite
PublikacjaAn experimental and theoretical study is reported to investigate the influence of bromine doping on CH3NH3Pb(I1−xBrx)3 perovskite for Br compositions ranging from x = 0 to x = 0.1, in which the material remains in the tetragonal phase. The experimental band gap is deduced from UV−vis absorption spectroscopy and displays a linear behavior as a function of bromine concentration. Density functional theory calculations are performed...
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Miniaturized Dual-Band SIW-Based Bandpass Filters Using Open-Loop Ring Resonators
PublikacjaThis article presents two novel architectures of dual-band substrate integrated waveguide (SIW) bandpass filters (BPFs). Initially, two identical open-loop ring resonators (OLRRs) are coupled face-to-face on the top of the SIW cavity to realize a dual-band single-pole BPF. To obtain two-pole dual-band characteristics, two OLRRs resonant units are assembled horizontally within the top metal layer of the SIW, which is a technique...
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Role of nitrogen in evolution of sp2/sp3 bonding and optical band gap in hydrogenated carbon nitride
PublikacjaDrastic changes in the bonding are found in amorphous hydrogenated carbon nitride (a-CNx:H) film as a function of nitrogen concentration (or N/C ratio). The total C-sp3 fraction and hardness shows a sharp decrease (at N/C = 0.40) whereas optical band gap and resistivity shows a gradual increase as nitrogen concentration increases from 0.07 to 0.58. Raman spectrum of a-CNx:H film is fitted with both Gaussian (integrated intensity...
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High-Gain Compact Circularly Polarized X-Band Superstrate Antenna for CubeSat Applications
PublikacjaIn this letter, a concept of high-gain circularly polarized X-band antenna employing a partially reflecting surface (PRS) has been presented. In the initial antenna analysis, the influence of parasitic elements size in the PRS structure on antenna radiation pattern parameters has been investigated and the optimal arrangement of the elements has been identified. The proposed antenna provides wide bandwidth of return loss above 10...
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A Compact Self-Hexaplexing Antenna Implemented on Substrate-Integrated Rectangular Cavity for Hexa-Band Applications
PublikacjaThis brief introduces a novel architecture of a compact self-hexaplexing antenna (SHA) implemented on a substrate-integrated rectangular cavity (SIRC) for hexa-band applications. The proposed SHA is configured by using an SIRC resonator, two Pi-shaped slots (PSSs), and six 50Ω microstrip feedlines. The PSSs are connected back-to-back and loaded on top of the SIRC resonator to produce six patch radiators (PRs). The PRs are excited...
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Triple-objective models for portfolio optimisation with symmetric and percentile risk measures
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Triple dermoid sinus in sacro-caudal region in Rhodesian Ridgeback dog.
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MCSA with Normalized Triple Covariance as a bearings diagnostic indicator in an induction motor
PublikacjaStatistics of bearing failures in induction motors indicate, that they constitute more than 40% of IM damage, therefore bearing diagnosis is very important. Vibration methods for bearing diagnostics have one major disadvantage - they require the availability of the machine for sensors installation. This is the reason for seeking new methods based on motor supply current analysis. Diagnosis of induction motors, conducted remotely...