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Wyniki wyszukiwania dla: MICROWAVE MODELING
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Long-working-distance Raman system for monitoring of uPA ECR CVD process of thin diamond/DLC layers growth
PublikacjaW artykule przedstawiono konstrucję systemu optoelektronicznego do monitoringu ramanowskiego in-situ procesu μPA ECR CVD (ang.: Microwave Plasma Assisted Electron Cyclotron Resonance Chemical Vapour Deposition), stosowanego do osadzania cienkich warstw diamentowych i diamentopodobnych DLC. System ma budowę modułową i wyposażony jest w dedykowane sondy optyczne. Przedstawiono wyniki pomiarów testowych, potwierdzjące, że system posiada...
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GPU Acceleration of Multilevel Solvers for Analysis of Microwave Components With Finite Element Method
PublikacjaThe letter discusses a fast implementation of the conjugate gradient iterative method with ${rm E}$-field multilevel preconditioner applied to solving real symmetric and sparse systems obtained with vector finite element method. In order to accelerate computations, a graphics processing unit (GPU) was used and significant speed-up (2.61 fold) was achieved comparing to a central processing unit (CPU) based approach. These results...
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Expedited Multi-Objective Design Optimization of Miniaturized Microwave Structures Using Physics-Based Surrogates
PublikacjaIn this paper, a methodology for fast multi-objective design optimization of compact microwave circuits is presented. Our approach exploits an equivalent circuit model of the structure under consideration, corrected through implicit and frequency space mapping, then optimized by a multi-objective evolutionary algorithm. The correction/optimization of the surrogate is iterated by design space confinement and segmentation based on...
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Reduced-cost optimization-based miniaturization of microwave passives by multi-resolution EM simulations for internet of things and space-limited applications
PublikacjaStringent performance specifications along with constraints imposed on physical dimensions, make the design of contemporary microwave components a truly onerous task. In recent years, the latter demand has been growing in importance, with the innovative application areas such as Internet of Things coming into play. The need to employ full-wave electromagnetic (EM) simu-lations for response evaluation, reliable yet CPU heavy, only...
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Ionic Liquids and Deep Eutectic Mixtures: Sustainable Solvents for Extraction Processes
PublikacjaIn recent years, ionic liquids and deep eutectic mixtures have demonstrated great potential in extraction processes relevant to several scientific and technological activities. This review focuses on the applicability of these sustainable solvents in a variety of extraction techniques, including but not limited to liquid- and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound-assisted extraction and pressurized...
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Optical properties of boron-doped nanocrystalline diamond films studied by spectroscopic ellipsometry
PublikacjaThe optical properties of boron-doped nanocrystalline diamond films, coated using Microwave Plasma Enhanced Chemical Vapour Deposition (μPE CVD) system, were analyzed by spectroscopic ellipsometry. Diamond films were deposited on silicon substrates. The ellipsometry data (refractive index (n(λ)), extinction coefficient (k(λ)) were modeled using dedicated software. Evolution of the optical structure with boron doping was observed...
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An Improvement of Global Complex Roots and Poles Finding Algorithm for Propagation and Radiation Problems
PublikacjaAn improvement of the recently developed global roots finding algorithm has been proposed. The modification allows to shorten the computational time by reducing the number of function calls. Moreover, both versions of the algorithms (standard and modified) have been tested for numerically defined functions obtained from spectral domain approach and field matching method. The tests have been performed for three simple microwave...
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Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublikacjaConsidering the limitations of currently available technologies for the realization of microwave components and antennas, a trade-off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional PCB fabrication technology, thus are low cost and light weight. Moreover,...
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Compressed Projection Bases for Model-Order Reduction of Multiport Microwave Components Using FEM
PublikacjaThis paper presents a projection basis compression technique for generating compact reduced-order models (ROM) in the FE analysis of microwave devices. In this approach redundancy is removed from the projection basis by means of the proper orthogonal decomposition technique applied to the projected system of linear equations. Compression allows for keeping the size of a reduced-order model as small as possible without compromising...
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Microwave Alignment and Displacement Sensors in Groove Gap Waveguide Technology
PublikacjaThis paper is aimed at presenting highly sensitive microwave displacement and alignment sensors. With this goal, the method of realizing mechanically tunable cavity resonators in groove gap waveguides technology is presented. The resonance frequency of the cavity is then used for displacement sensing. It is also demonstrated that the symmetry properties of a pair of groove gap waveguide cavities can be used to improve the robustness...
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Microwave Ring Resonator Based Pressure Sensor
PublikacjaThis paper demonstrates a microwave pressure sensor, which is based on microstrip line-fed ring resonators. The first ring resonator is loaded with the concentric cylindrical shafts, while the same number of the hollow shanks as the shafts are mounted on the second ring resonator. The arrangement of the cylindrical shaft and hollow shank allows for mechanical movement between two substrates while maintaining electrical contact....
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Al-DIAMOND SCHOTTKY TUNNEL DIODES WITH BARRIER HEIGHT CONTROL
PublikacjaFew-nanometer-thick very highly boron-doped p-type layers were fabricated at metal-semiconductor interfaces of Schottky barrier diodes formed with aluminum on polycrystalline diamond. Preliminary results show that hermionically-assisted tunneling mechanism results in lower voltage drops at forward biasing of these diodes than expected for the Al-diamond metal-semiconductor potential barrier B. The effective barrier height Bpeff...
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A Trisection Filter Design With Negative Slope of Frequency-Dependent Crosscoupling Implemented in Substrate Integrated Waveguide (SIW)
PublikacjaThis letter reports on a novel realization of a microwave bandpass filter in a triplet configuration with a frequency-dependent crosscoupling implemented in substrate integrated waveguide (SIW). The design involves implementing dispersive coupling with a negative slope, a feature that allows the capabilities of the classic triplet topology to be extended. In this particular case, the implementation of two transmission zeros on...
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Computationally Efficient Design Optimization of Compact Microwave and Antenna Structures
PublikacjaMiniaturization is one of the important concerns of contemporary wireless communication systems, especially regarding their passive microwave components, such as filters, couplers, power dividers, etc., as well as antennas. It is also very challenging, because adequate performance evaluation of such components requires full-wave electromagnetic (EM) simulation, which is computationally expensive. Although high-fidelity EM analysis...
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Magnetic field mapping along a NV-rich nanodiamond-doped fiber
PublikacjaIntegration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows...
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Design of novel highly sensitive sensors for crack detection in metal surfaces: theoretical foundation and experimental validation
PublikacjaThe application of different types of microwave resonators for sensing cracks in metallic structures has been subject of many studies. While most studies have been focused on improving the sensitivity of planar crack sensors, the theoretical foundation of the topic has not been treated in much detail. The major objective of this study is to perform an exhaustive study of the principles and theoretical foundations for crack sensing...
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Computationally-Efficient Statistical Design and Yield Optimization of Resonator-Based Notch Filters Using Feature-Based Surrogates
PublikacjaModern microwave devices are designed to fulfill stringent requirements pertaining to electrical performance, which requires, among others, a meticulous tuning of their geometry parameters. When moving up in frequency, physical dimensions of passive microwave circuits become smaller, making the system performance increasingly susceptible to manufacturing tolerances. In particular, inherent inaccuracy of fabrication processes affect...
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Machine-Learning-Based Global Optimization of Microwave Passives with Variable-Fidelity EM Models and Response Features
PublikacjaMaximizing microwave passive component performance demands precise parameter tuning, particularly as modern circuits grow increasingly intricate. Yet, achieving this often requires a comprehensive approach due to their complex geometries and miniaturized structures. However, the computational burden of optimizing these components via full-wave electromagnetic (EM) simulations is substantial. EM analysis remains crucial for circuit...
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Fast Machine-Learning-Enabled Size Reduction of Microwave Components Using Response Features
PublikacjaAchieving compact size has emerged as a key consideration in modern microwave design. While structural miniaturization can be accomplished through judicious circuit architecture selection, precise parameter tuning is equally vital to minimize physical dimensions while meeting stringent performance requirements for electrical characteristics. Due to the intricate nature of compact structures, global optimization is recommended,...
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Tolerance-Aware Optimization of Microwave Circuits by Means of Principal Directions and Domain-Restricted Metamodels
PublikacjaPractical microwave design is most often carried out in the nominal sense. Yet, in some cases, performance degradation due to uncertainties may lead to the system failing to meet the prescribed specifications. Reliable uncertainty quantification (UQ) is therefore important yet intricate from numerical standpoint, especially when the circuit at hand is to be evaluated using electromagnetic (EM) simulation tools. Tolerance-aware...
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Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet
PublikacjaThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number...
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Computationally efficient two-objective optimization of compact microwave couplers through corrected domain patching
PublikacjaFinding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective...
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A Compact Basis for Reliable Fast Frequency Sweep via the Reduced-Basis Method
PublikacjaA reliable reduced-order model (ROM) for fast frequency sweep in time-harmonic Maxwell’s equations by means of the reduced-basis method is detailed. Taking frequency as a parameter, the electromagnetic field in microwave circuits does not arbitrarily vary as frequency changes, but evolves on a very low-dimensional manifold. Approximating this low-dimensional manifold by a low dimension subspace, namely, reduced-basis space, gives...
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Optoelectronic system for investigation of cvd diamond/DLC layers growth
PublikacjaDevelopment of the optoelectronic system for non-invasive monitoring of diamond/DLC (Diamond-Like-Carbon) thin films growth during μPA ECR CVD (Microwave Plasma Assisted Electron Cyclotron Resonance Chemical Vapour Deposition) process is described. The system uses multi-point Optical Emission Spectroscopy (OES) and long-working-distance Raman spectroscopy. Dissociation of H2 molecules, excitation and ionization of hydrogen atoms...
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Rapid multi-objective simulation-driven design of compact microwave circuits
PublikacjaA methodology for rapid multi-objective design of compact microwave circuits is proposed. Our approach exploits point-by-point Pareto set identification using surrogate-based optimization techniques, auxiliary equivalent circuit models, and space mapping as the major model correction method. The proposed technique is illustrated and validated through the design of a compact rat-race coupler. A set of ten designs being trade-offs...
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A Compact and Lightweight Microwave Tilt Sensor Based on an SRR-Loaded Microstrip Line
PublikacjaIn this paper, the symmetry property of split ring resonators (SRRs) is exploited to develop a tilt sensor. The sensor is composed of an SRR-loaded microstrip line operating at microwave frequencies. It is shown that the depth of notch in the reflection characteristic of the microstrip is a function of the tilt angle of the SRR. Thus, it can be used for sensing inclination. The sensor benefits from very compact size and light weight....
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Nitrogen-doped diamond thin films: potential application in Fabry-Pérot interferometer
PublikacjaIn this paper we present results of preliminary research of using nitrogen-doped diamond (NDD) films as reflective layer in Fabry-Pérot interferometer. NDD films were deposited on Si substrates by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) with the use of CH4, H2 and N2 gas mixtures. During deposition process methane flow rate varied while nitrogen flow was constant. We performed series of measurements which showed...
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Fast multi-criterial statistical analysis and design optimization of compact microwave couplers
Publikacja—A rapid statistical analysis and yield estimation of compact microwave couplers involving multiple performance parameters has been presented. The analysis is realized using a fast surrogate model representing appropriate characteristic points of the coupler response. Because of less nonlinear dependence of the characteristic points on the structure geometry (compared to the original response, i.e., S-parameters vs. frequency),...
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Assessing the industrialization progress of hydrodynamic cavitation process intensification technology: a review
PublikacjaHydrodynamic cavitation (HC) is widely acknowledged as a promising green approach for enhancing various production and waste management processes, such as water treatment, sludge pretreatment, lignocellulosic biomass (LCB) pretreatment, emulsification, and food processing. Despite demonstrating superior industrialization potential compared with other emerging technologies such as ultrasound and microwave, the widespread commercial...
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Nested Kriging Surrogates for Rapid Multi-Objective Optimization of Compact Microwave Components
PublikacjaA procedure for rapid EM-based multi-objective optimization of compact microwave components is presented. Our methodology employs a recently developed nested kriging modelling to identify the search space region containing the Pareto-optimal designs, and to construct a fast surrogate model. The latter permits determination of the initial Pareto set, further refined using a separate surrogate-assisted process. As an illustration,...
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Influence of dopants on structure of polycrystalline bismuth niobate
PublikacjaBismuth niobate (BiNbO4) has attracted attention as a low-fired ceramics with promising microwave application potential. BiNbO4 ceramics was fabricated by mixed oxide method and sintered at temperature T<1000˚C. As the sintering aids a small amount of CuO oxide was used. The crystalline structure of the ceramic samples was examined by X-ray diffraction method at room temperature. The Rietveld refinement method was used for analysis...
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Local mesh morphing technique for parametrized macromodels in the finite element method
PublikacjaThis paper presents a novel approach for enhancing the efficiency of the design process of microwave devices by means of the finite element method. It combines mesh morphing with local model order reduction (MOR) and yields parametrized macromodels that can be used to significantly reduce the number of variables in the FEM system of equations and acceleration of computer simulation. A projection basis for local reduction is generated...
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Salicylaldimine-based receptor as a material for iron(III) selective optical sensing
Publikacjaα,α-Bis(salicylimino)-m-xylene (L) was prepared using both conventional and microwave-assisted procedure. The compound exhibits ability to colorimetric recognition of iron(III) ions in aqueous environment, what is shown by significant color change from yellow to purple. In DMSO : water (9:1 v/v) solvent system receptor creates with iron(III) cations complexes of 2:1 stoichiometry (L:Fe3+) with stability constant (log K) 7.54±0.21....
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Estimation of Broadband Complex Permeability Using SIW Cavity-Based Multimodal Approach
PublikacjaIn this article, an attractive multimodal substrate integrated waveguide (SIW) based methodology is presented for the characterization of magnetic materials in the broadband microwave frequency. The proposed approach employs a modified feed under-coupled SIW cavity instead of conventional feed over-coupled multiple SIW cavities; it uses the modified closedform expression, developed from the first principle to consider the effect...
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Rapid and Reliable Re-Design of Miniaturized Microwave Passives by Means of Concurrent Parameter Scaling and Intermittent Local Tuning
PublikacjaRe-design of microwave passive components for the assumed operating frequencies or substrate parameters is an important yet a tedious process. It requires simultaneous tuning of relevant circuit variables, often over broad ranges thereof, to ensure satisfactory performance of the system. If the operating conditions at the available design are distant from the intended ones, local optimization is typically insufficient, whereas...
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On Improved-Reliability Design Optimization of High-Frequency Structures Using Local Search Algorithms
PublikacjaThe role of numerical optimization has been continuously growing in the design of high-frequency structures, including microwave and antenna components. At the same time, accurate evaluation of electrical characteristics necessitates full-wave electromagnetic (EM) analysis, which is CPU intensive, especially for complex systems. As rigorous optimization routines involve repetitive EM simulations, the associated cost may be significant....
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Near-Field Wireless Sensing of Plastics and Papers Using Frugal Peel-Off Passive Tag
PublikacjaThis article presents a novel frugal approach of testing plastics and papers using a near-field microwave sensing technique with a peel-off tag. The proposed sensing technique involves two electrical entities: the sensor, which may be regarded as a reader, and a disposable tag. The reader is a modified design of a gap-coupled microstrip line (GCML) sensor, while the passive tag is a standard double-ring complementary split-ring...
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Review of Recent Advancement on Nature/Bio-inspired Antenna Designs
PublikacjaThis article presents an extensive examination of antennas rooted in nature and biology, showcasing their remarkable performance across a wide spectrum of frequencies—from microwave to terahertz. The limitations of traditional antenna design have become increasingly evident in the face of burgeoning demands for novel communication technologies. Conventional analytical-equation-based approaches struggle to deliver the combined performance...
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ZnO-decorated green-synthesized multi-doped carbon dots from Chlorella pyrenoidosa for sustainable photocatalytic carbamazepine degradation
PublikacjaThe promising green synthesis of carbon dots (CDs) from microalga Chlorella pyrenoidosa was achieved using simple hydrothermal and microwave-assisted methods. Doping of nanomaterials by nonmetals (N, S, and P) was confirmed by X-ray photoelectron spectroscopy (XPS), while the existence of metals in the CDs was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and transmission electron microscopy (TEM),...
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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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On Decision-Making Strategies for Improved-Reliability Size Reduction of Microwave Passives: Intermittent Correction of Equality Constraints and Adaptive Handling of Inequality Constraints
PublikacjaDesign optimization of passive microwave components is an intricate process, especially if the primary objective is a reduction of the physical size of the structure. The latter has become an important design consideration for a growing number of modern applications (mobile communications, wearable/implantable devices, internet of things), where miniaturization is imperative due to a limited space allocated for the electronic circuitry....
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Developments in Green Chromatography
PublikacjaGreen analytical chemistry is a widely recognized concept that has led to the development of new analytical methods with reduced environmental impact and minimized analyst occupational exposure. Achievements include the development of microextraction, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) techniques. Research towards greener separation processes focuses on the elimination of toxic solvents...
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A Substrate Integrated Waveguide (SIW) Bandpass Filter in A Box Configuration With Frequency-Dependent Coupling
PublikacjaThis letter presents the design of a microwave bandpass filter with frequency-dependent coupling implemented in substrate integrated waveguide (SIW) technology. The proposed filter implements a four-pole generalized Chebyshev filtering function with two transmission zeros. Resonators are arranged in an extended box configuration with dispersive coupling on a main signal path, which produces an extra zero in comparison to classical...
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On the low-cost design of abbreviated multisection planar matching transformer
PublikacjaA numerically demanding wideband matching transformer composed of three nonuniform transmission lines (NUTLs) has been designed and optimized at a low computational cost. The computational feasibility of the design has been acquired through the exploitation of low-fidelity NUTL models in most steps of the design procedure and an implicit space mapping optimization engine, providing high accuracy results with only a handful of EM...
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Effect of microwave and convection heating on selected nutrients of human milk
PublikacjaThe aim of this study was to determine the influence of the microwave heating method (MWH) on selected determinants of the nutritional value of human milk (HM) and compare to the effect exerted by the standard convection heating (CH) method, including holder pasteurization (HoP). It was showed that using MWH under conditions assumed to ensure microbiological safety, changes in the level of the nutrients were not observed. In these...
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A Novel Synthesis Technique for Microwave Bandpass Filters with Frequency-Dependent Couplings
PublikacjaThis paper presents a novel synthesis technique for microwave bandpass filters with frequency-dependent couplings. The proposed method is based on the systematic extraction of a dispersive coupling coefficient using an optimization technique based on the zeros and poles of scattering parameters representing two coupled resonators.The application of this method of synthesis is illustrated using two examples involving four and five-pole...
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Application of thin diamond films in low-coherence fiber-optic Fabry Pérot displacement sensor
PublikacjaThe novel fiber-optic low coherence sensor with thin diamond films is demonstrated. The undoped and boron-doped diamond films were elaborated by the use of the microwave plasma enhanced chemical vapor deposition (μPE CVD) system. The optical signal from the Fabry–Pérot cavity made with the application of those thin films is sensitive to displacement. The sensor characterization was made in the range of 0–600 μm. The measurements...
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Fast Full-Wave Multilevel Zero-Pole Optimization of Microwave Filters
PublikacjaA new concept is proposed for the full-wave computer-aided design of microwave filters. The method consists of two stages and operates on the zeros and poles of the transfer function and their derivatives. These quantities are evaluated from the response computed by a full-wave electromagnetic solver with two levels of accuracy. The two stages make use of different models that are optimized using a low-accuracy electromagnetic...
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A robust design of a numerically demanding compact rat-race coupler
PublikacjaA fast and accurate design procedure of a computationally expensive microwave circuit has been presented step-by-step and experimentally validated on the basis of a compact rat-race coupler (RRC) comprising slow-wave resonant structures (SWRSs). The final compact RRC solution has been obtained by means of a sequential optimization scheme exploiting the implicit space mapping (ISM) algorithm. A well-suited surrogate optimization...
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A Multifunctional Microwave Filter/Sensor Component Using a Split Ring Resonator Loaded Transmission Line
PublikacjaThis research is focused on the design and realiza2 tion of a microwave component with multifunctional filter/sensor 3 operation using a resonator-loaded transmission line (TL). It is 4 shown that while the structure acts as a bandstop filter, the 5 phase of the reflection coefficient from the loading resonator(s) 6 on a movable layer can be used for displacement sensing, thus 7 allowing for combining filtering with sensing in...