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Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Nonresonant Nodes and Arbitrary Frequency-Variant Reactive Couplings
PublikacjaA novel, general circuit-level description of coupledresonator microwave filters is introduced in this article. Unlike well-established coupling-matrix models based on frequency-invariant couplings or linear frequency-variant couplings (LFVCs), a model with arbitrary reactive frequencyvariant coupling (AFVC) networks is proposed. The engineered formulation is more general than prior-art ones—with the only restriction that the coupling...
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Comparative Analysis of Developed Rainfall Intensity–Duration–Frequency Curves for Erbil with Other Iraqi Urban Areas
PublikacjaRainfall Intensity–Duration–Frequency (IDF) relationships are widely used in water infrastructure design and construction. IDF curves represent the relationship between rainfall intensity, duration, and frequency, and are obtained by analyzing observed data. These relationships are critical for the safe design of flood protection structures, storm sewers, culverts, bridges, etc. In this study, the IDF curves and empirical IDF formulas...
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What is in a name: Defining “high entropy” oxides
PublikacjaABSTRACT High entropy oxides are emerging as an exciting new avenue to design highly tailored functional behaviors that have no traditional counterparts. Study and application of these materials are bringing together scientists and engineers from physics, chemistry, and materials science. The diversity of each of these disciplines comes with perspectives and jargon that may be confusing to those outside of the individual fields,...
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HIGH TEMPERATURE HEAT PUMPS – PERSPECTIVE HEATING SYSTEMS?
PublikacjaIn the paper presented are authors own concepts of high temperature compressor heat pumps for the utilisation of medium and low temperature sources of heat. Working fluids for use in high temperature heat pumps are discussed, as well as the criteria for their selection. Analyses are presented for the production of in the upper steam source at 130 °C. One-stage systems and cascade systems were analyzed. An analysis of the coefficient...
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Frequency-Variant Double-Zero Single-Pole Reactive Coupling Networks for Coupled-Resonator Microwave Bandpass Filters
PublikacjaIn this work, a family of frequency-variant reactive coupling (FVRC) networks is introduced and discussed as new building blocks for the synthesis of coupled-resonator bandpass filters with real or complex transmission zeros (TZs). The FVRC is a type of nonideal frequency-dependent inverter that has nonzero elements on the diagonal of the impedance matrix, along with a nonlinear frequency-variation profile of its transimpedance...
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Shielded HMSIW-based frequency-tunable self-quadruplexing antenna using different solid/liquid dielectrics
PublikacjaThis article proposes a frequency-tunable self-quadruplexing antenna based on a shielded half-mode substrate integrated waveguide (S-HMSIW). In order to reduce the size of the HMSIW cavity resonator and to obtain quad-band characteristics, a modied E-shaped slot is engraved on the top of the metal. The experimental validation is carried out after analyzing the data using a circuit model. Flexibility of each resonant frequency is...
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Internacjonalizacja przedsiębiorstw z branż high-tech
PublikacjaW artykule opisano kluczowe teorie internacjonalizacji przedsiębiorstw, specyfikę internacjonalizacji firm z branż high-tech, przede wszystkim ich wczesną i szybką internacjonalizację, motywy i uwarunkowania oraz wybrane modele internacjonalizacji. W podsumowaniu wskazano na dalsze kierunki badań
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Resonator-Loaded Waveguide Notch Filters with Broad Tuning Range and Additive-Manufacturing-Based Operating Frequency Adjustment Procedure
PublikacjaThis article presents a new class of ring-resonator-loaded waveguide notch filters with a broad tuning range, low cost, and improved performance. The proposed approach employs a comple-mentary asymmetric split ring resonator coupled to a microstrip transmission line and excited in a rectangular waveguide. An equivalent circuit model is proposed to explain the working principle of the proposed notch filter. The adjustment of the...
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Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
PublikacjaThe nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and...
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Charge Transport in High-Entropy Oxides
PublikacjaThis work presents the results of research on the transport properties of the high-entropy BaZr1/8Hf1/8Sn1/8Ti1/8Y1/8In1/8Sm1/8Yb1/8O3–x perovskite oxide with special focus on proton transport. The presented study is part of broader work in which we focus on multiple different chemical compositions with the cation number varying from 5 up to 12 (in B-sublattice). The presence of proton defects is analyzed with thermogravimetry,...
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High temperature corrosion resistance of porous hastelloy alloy
PublikacjaTo further understand the suitability of Ni-Cr-base alloy for solid oxide fuel cell (SOFC), a commercial Ni-Cr-Fe-Mo alloy, Hastelloy X was selected and evaluated for oxidation behaviour under high temperature conditions. HastelloyX was chosen due to its unusual resistance to oxidizing, reducing and neutral atmospheres. For long term stability of metal supported fuel cell, the corrosion resistance plays a vital role and must be...
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Modified Preisach model of hysteresis in multi air gap ferrite core medium frequency transformer
PublikacjaThis article presents the modified Preisach model of hysteresis for a 3-phase medium frequency transformer in a 100 kW dual active bridge converter. The transformer magnetic core is assembled out of ferrite I-cores, which results in multiple parasitic air gaps. For this transformer, the hysteresis loops were measured and parameters of the Preisach model were determined. The Preisach distribution function is approximated with a...
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Internationalization patterns of Polish family high-tech firms
PublikacjaThe objective of the article is to explore internationalisation patterns of family high-tech firms, especially their internationalisation motives, intensity, speed, and entry modes. The empirical part adopts a quantitative approach. The results of the survey are presented on the sample of 263 high-tech production firms from Poland, including 101 family firms. The survey was conducted in all 16 Polish regions. The calculations from...
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Lagrangian model of an isolated dc-dc converter with a 3-phase medium frequency transformer accounting magnetic cross saturation
PublikacjaThis article presents a nonlinear equivalent circuit model of an isolated dc-dc converter with a 3-phase medium frequency transformer. The model takes into account the magnetic cross saturation of the 3-phase core-type magnetic circuit. The model is suitable in detailed electromagnetic transient simulations of power systems involving isolated dc-dc converters. The model is developed using the Lagrange energy method. It involves...
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UWB Microstrip Antennas on a Cylindrical Surfaces
PublikacjaConformal antennas are becoming popular due to their many advantages and possibilities of applications they offer. The advantages of using antennas with a curved surface arise not only from the possibility of integrating them with the object on which they are mounted on but also from the increase, relatively to planar antennas, of their visible angular range. The circular antenna arrays, or arrays of radiators located on the surface...
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Patch size setup and performance/cost trade-offs in multi-objective EM-driven antenna optimization using sequential domain patching
PublikacjaPurpose This paper aims to assess control parameter setup and its effect on computational cost and performance of deterministic procedures for multi-objective design optimization of expensive simulation models of antenna structures. Design/methodology/approach A deterministic algorithm for cost-efficient multi-objective optimization of antenna structures has been assessed. The algorithm constructs a patch connecting extreme Pareto-optimal...
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Badanie i analiza dokładności estymacji położenia obiektów ruchomych w hybrydowym systemie lokalizacyjnym
PublikacjaW niniejszej rozprawie dyskusji poddano dokładność lokalizacji poruszających się osób w środowiskach wewnątrzbudynkowych. W świetle bieżących oczekiwań służb państwowych, czy też podmiotów gospodarczych znajomość położenia osób wewnątrz budynków jest niezwykle ważna, lecz jego określenie jest problematyczne np. z racji utrudnionej propagacji sygnałów radiowych. W rozprawie przedstawiono propozycję budowy hybrydowego systemu lokalizacyjnego,...
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Optimization of clamping stiffness during milling of high-dimensional structures with the use of techniques of experiment – aided virtual prototyping
PublikacjaThe subject of this paper is a method of searching for conditions of minimizing the vibration level of a tool-high dimensional flexible workpiece, at unchangeable technological parameters of the machining process. It depends on repeatable change of the values of the stiffness coefficients as soon as an optimal vibration state of the workpiece approaches. There are assessed the values of dominant ”peaks” in the frequency spectra...
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Perspectives for high resolution and high light output LuAP:Ce crystals
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Laboratory Load Model Based on 150 kVA Power Frequency Converter and Simulink Real-Time – Concept, mplementation, Experiments
PublikacjaFirst section of the paper provides technical specification of laboratory load model basing on 150 kVA power frequency converter and Simulink Real-Time platform. Assumptions, as well as control algorithm structure is presented. Theoretical considerations based on criteria which load types may be simulated using discussed laboratory setup, are described. As described model contains transformer with thyristor-controlled tap changer,...
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ALTERNATIVE, DIRECT SYNTHESIS METHOD OF THE CERAMIC SOLID SOLUTIONS BASED ON BaTiO3 THROUGH A HIGH ENERGY BALL MILLING
PublikacjaPolycrystalline samples BaTiO3 and the solid solutions Ba0.9Sr0.1TiO3, Ba0.9Sr0.1Ti0.9Sn0.1O3, Ba0.9Sr0.1Ti0.8Sn0.2O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure...
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Effective Permeability of Multi Air Gap Ferrite Core 3-Phase Medium Frequency Transformer in Isolated DC-DC Converters
PublikacjaThe magnetizing inductance of the medium frequency transformer (MFT) impacts the performance of the isolated dc-dc power converters. The ferrite material is considered for high power transformers but it requires an assembly of type “I” cores resulting in a multi air gap structure of the magnetic core. The authors claim that the multiple air gaps are randomly distributed and that the average air gap length is unpredictable at the...
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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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Coupled-Resonator Waveguide Filter in Quadruplet Topology With Frequency-Dependent Coupling - A Design Based on Coupling Matrix
PublikacjaThis letter presents an application of a recently developed coupling matrix synthesis technique to design of coupled-resonator filters with dispersive inter-resonator couplings. This technique is used to design a novel coupled-cavity bandpass filter. Measurements validate the design and confirm effectiveness of the synthesis method. The filter is a four-pole generalized Chebyshev filter with three transmission zeros. Resonators...
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High-efficient, zero-emission energy production
PublikacjaThis paper presents innovative thermodynamiccycles with high-efficient, zero-emission energy production. The main aim of this work is to show the role of nano-phenomena in the enhancement of the power of thermodynamic cycles. For that purpose, the cycles using oxy-combustion and spray ejected condensation are first studied and, secondly hybrid cycles using fuel cells and gas turbines are presented. The role of nano-phenomena in...
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Frequency of use, moral incongruence, and religiosity and their relationships with self-perceived addiction to pornography, internet use, social networking and online gaming
PublikacjaBackground and Aims Moral incongruence involves disapproval of a behaviour in which people engage despite their moral beliefs. Although considerable research has been conducted on how moral incongruence relates to pornography use, potential roles for moral incongruence in other putative behavioural addictions have not been investigated. The aim of this study was to investigate the role of moral incongruence in self‐perceived...
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Determination of high-intensity sweeteners in beverages by high-performance liquid chromatography with mass spectrometry detection.
PublikacjaThe objective of the present study was to measure the concentration of nine high intensity sweeteners (acesulfame-K, aspartame, alitame, cyclamate, dulcin, neohesperidin dihydrochalcon, neotame, saccharin and sucralose) in different types of beverages available on the polish market. The proposed methodology reported here consists of a extraction with buffer composed of formic acid and N,N-diisopropylethylamine (pH 4.5) followed...
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Multi-Site Cation Control of Ultra-Broadband Near-Infrared Phosphors for Application in Light-Emitting Diodes
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Person Tracking in Ultra-Wide Band Hybrid Localization System Using Reduced Number of Reference Nodes
PublikacjaIn this article a novel method of positional data integration in an indoor hybrid localization system combining inertial navigation with radio distance measurements is presented. A point of interest is the situation when the positional data and the radio distance measurements are obtained from less than thee reference nodes and it is impossible to unambiguously localize the moving person due to undetermined set of positional equations....
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Weldability of high strength steels in wet welding conditions
PublikacjaIn this paper are characterized problems of high strength steel weldability in underwater wet welding conditions. Water as a welding environment intensifies action of unfavourable factors which influence susceptibility to cold cracking of welded steel joints. The susceptibility to cold cracking of S355J2G3 steel and S500M steel in wet conditions was experimentally estimated (by using Tekken test). It was concluded that the steels...
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On the use of instantaneous complex frequency for pitch and formant tracking.
PublikacjaW pracy opisano algorytm śledzenia częstotliwości podstawowej i formantów mowy z wykorzystaniem zespolonej pulsacji chwilowej. Działanie algorytmu przetestowano na nagraniach polskich samogłosek, których wysokość zmieniała się płynnie. Wyniki testów wraz z porównaniem działania opisanej metody i metody predykcji liniowej zawarto w artykule.
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Digital measurement of frequency with linear interpolation in dynamic states
PublikacjaPrzedstawiono metody rejestracji częstotliwości sygnałów impulsowych. Zastosowanie interpolacji pozwala na uzyskanie wyniku dla dowolnej chwili. Opisano pracę w trybie on-line i off-line.
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Frequency dispersion of harmonic components of the current of an electrode process
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Impedance matching in dual-frequency induction heating systems
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Thermal heat-balance mode flow-to-frequency converter
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Online pitch estimation using instantaneous complex frequency
PublikacjaW pracy opisano nowe wyniki dotyczące skuteczności algorytmu potokowego estymującego częstotliwość podstawową sygnału mowy. Algorytm wykorzystuje zespoloną pulsację chwilową dla klasyfikacji mowy na dźwięczną i bezdźwięczną oraz estymacji częstotliwości podstawowej dla każdej próbki sygnału. Skuteczność klasyfikacji oraz dokładność estymacji zostały ocenione eksperymentalnie z wykorzystaniem dwóch baz nagrań, zawierających wypowiedzi...
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Corrosion monitoring by frequency intermodulation technique employing Gabortransformation
PublikacjaMonitorowano proces korozji zachodzący na stali ST3S w środowisku obojętnym. Wykonane zostały badania harmoniczne techniką intermodulacji częstotliwościowej. W analizie harmonicznej zastosowana została nowa metoda czasowo-częstotliwościowej tzw. transformacji Gabora. Wykazane zostało, że transformacja Gabora może być przydatna w monitorowaniu korozji w warunkach dynamicznych. Transformacja Gabora pozwala na dobrą reprezentację...
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Automated design of waveguide filters with frequency-dependent couplings.
PublikacjaW artykule zaproponowano szybką technikę pozwalającą na automatyczne projektowanie filtrów falowodowych ze sprzężeniami zależnymi od częstotliwości. Procedura optymalizacyjna jest trójetapowa z różnymi funkcjami celu w każdym etapie.
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Voltage and frequency regulation of a standalone induction generator by reduced-rating power electronic compensators - comparative evaluation
PublikacjaIn this paper are considered two fundamental topologies of power electronic compensators for voltage and frequency control of a standalone self-excited induction generator (IG) system. These are voltage and current source inverter based shunt compensators with energy storage. The aim of this study is to assess main features of both topologies in dynamic and steady-state IG operation. The whole system is modelled with the aid of...
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Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection
PublikacjaAn analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages,...
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RSS-Based DoA Estimation in 802.11p Frequency Band Using ESPAR Antenna and PPCC-MCP Method
PublikacjaIn this paper, the concept of direction of arrival (DoA) estimation using electronically steerable parasitic array radiator (ESPAR) antenna designed to operate in IEEE 802.11p vehicular communication standard has been investigated with respect to different possible elevation angles of a radio frequency (RF) signal impinging the antenna. To this end, two different possible sets of the 3D antenna radiation patterns have been used...
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Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublikacjaGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
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Frequency and phase analysis of daily reprocessed solutions from selected EPN stations relating to geological phenomena,
PublikacjaThe main assumption of this research was to check and verify the behaviour of a few EPN (European Permanent Network) stations on both sides of the Teisseyre-Tornquist zone (T-T zone), which is located on Polish territory and crosses Poland almost in half. The selected EPN stations’ time series were a subject of frequency and phase analysis. The main purpose of the research was to verify if there is any correspondence between stations...
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Characterization of Corrosion-Induced Fracture in Reinforced Concrete Beams Using Electrical Potential, Ultrasound and Low-Frequency Vibration
PublikacjaThe paper deals with the non-destructive experimental testing of the reinforced concrete beams under progressive corrosion. A series of experiments using electrical potential, ultrasound and low-frequency vibrations techniques are reported. Electrical potential and natural frequencies were used to characterise and monitor the corrosion process at its initial state. The P-wave velocity measurements were proved to be effective in...
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Inhibition of the granular anammox process by the high concentration of free ammonia.
PublikacjaHigh concentrations of ammonia and nitrite, typical for reject water treatment in the anammox process with the use of high temperatures and pH, may cause free ammonia (FA) inhibition. In this study, the inhibitory effect of FA on anammox process rate was investigated in a bench-scale sequencing batch reactor (SBR) with granular anammox biomass. Results of the study present that the anammox process could be successfully operated...
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The Impact of Homogeneity of High Modulus Asphalt Concrete Layer on Low-Temperature Cracking
PublikacjaDuring winter season of 2012 numerous transverse cracks developed in high-modulus asphalt concrete (HMAC) base of newly constructed motorway. Pavement cracked both in transverse joint locations and in the area between them. Research which was conducted during investigation of the causes and mechanisms of cracking consisted of: field examination, laboratory testing of specimens cored out of the existing pavement, computational analyses...
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Networking and Familiness as Factors Stimulating the Early Internationalization of High-Tech Firms
PublikacjaThe problem of the role and importance of time in the process of firm’s internationalization belongs to the mainstream of international business research, as is the problem of the key role of high-tech firms operating across borders. The main goal of the paper is to understand how selected factors determine early internationalization of high-tech firms in Poland as an emerging market. The theoretical framework of the article is...
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Compact and Integrated High-Power Pulse Generation and Forming System
PublikacjaThis paper presents comprehensive analytical, numerical and experimental research of the compact and integrated high-power pulse generation and forming system based on the flux compression generator and the electro-explosive forming fuse. The paper includes the analysis of the presented solution, starting from the individual components studies, i.e., the separate flux compression generator tests in field conditions and the forming...
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Highly-Compact Dual-Band Bandpass Waveguide Filter Based on Cross-Shaped Frequency-Dependent Coupling
PublikacjaThis work reports the design of an original class of highly-compact dual-band bandpass filter based on dual-mode waveguide resonators inter-coupled through a novel type of frequency-dependent coupling (FDC). The devised FDC consists of a cross-shaped metallic structure placed in the broad wall of a rectangular waveguide. This FDC produces two additional poles and three extra transmission zeros (TZs). Specifically, each pole is...
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Very high altitude micro air vehicle deployment method
PublikacjaThe paper presents the original work and method for high altitude micro air vehicle deployment. The method is based on the scientific ballooning, and adapted for stratospheric flight of commercial off-the-shelf micro air vehicle in flying wing configuration. The High Altitude Micro Air Vehicle, built for this research, was deployed during a test experiment at the lower level of the stratosphere. The results of the experiment and...