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Search results for: IEEE 11AH
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Quasi-static finite-element analysis of a skewed microstrip crossover
PublicationPrzedstawiono quasi statyczną analizę skrzyżowania mikroskopowego na podłożu dielektycznym. Mikropaski znajdują się na różnych warstwach układu planarnego i mogą krzyżować się pod dowolnym kątem. Pojemności i indukcyjności obliczane są na podstawie rozkładu potencjałów skalarnych. W sformułowaniu zagadnienia magnestatycznego warunki brzegowe dla potencjału skalarnego wprowadzono za pomocą powierzchni rozcięcia dziedziny analizy....
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A new class of eigenfunction expansion methods for fast frequency-domain analysis of waveguides
PublicationZaprezentowano nową technikę szybkiego obliczania charakterystyk dyspersyjnych falowodów z niejednorodnym wypełnieniem. Metoda ta oblicza przybliżone wartości stałej propagacji dla wymaganej częstotliwości, bazując na bardziej dokładnych wyliczeniach rozkładu pola i stałej propagacji dla kilku wybranych punktów częstotliwości.
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Characterization of rectangular waveguide with a pseudochiral omega slab
PublicationMetodę dopasowania rodzajów zastosowano do rozwiązania falowodu prostokątnego zawierającego materiał pseudochiralny typy Omega. Zdefiniowano własności rodzajów pola w badanej prowadnicy oraz zauważono wystąpienie efektu przemieszczenia pola. Określono pełnofalową macierz rozproszenia sekcji badanego falowodu oraz porównano wyniki symulacji charakterystyk transmisyjnych sekcji z eksperymentem. W oparciu o uzyskane wyniki dokonano...
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Automated CAD of coupled resonator filters
PublicationGradientowa metoda optymalizacji wraz z nową definicją funkcji celu opartą na rozkładzie biegunów oraz zer funkcji transmitancji obwodu, została zastosowana do pełnofalowej syntezy filtrów falowodowych pasmowo-przepustowych. Ekstrakcja biegunów wykonywana jest w oparciu metodę Cauchyłego. Przestawiona technika pozwana na znalezienie wymiarów geometrycznych struktur filtrujących o zadanej topologii bez konieczności wcześniejszej...
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Coupled - mode design of ferrite loaded coupled microstrip lines section
PublicationMetodę rodzajów sprzężonych zastosowano do analizy i projektowania sekcji ferrytowych mikropaskowych linii sprzężonych magnesowanych podłużnie (FCL). W wyniku analizy określono macierz rozproszenia sekcji oraz warunki umożliwiające jej zastosowanie do realizacji cyrkulatora projetowanego jako połączenie badanej sekcji FCL z mikropaskowym rozgałęzieniem typu T. W oparciu o opracowane oprogramowanie przeprowadzono modelowanie parametrów...
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Low-order models from FD-TD time samples
PublicationNiniejszy artykuł zawiera opis szeregu kryteriów pozwalających na automatyczne tworzenie wysokiej jakości modeli sygnałów czasowych uzyskanych w drodze symulacji obwodów wysokiej częstotliwości metodą różnic skończonych w dziedzinie czasu. Podany jest szczegółowy opis selekcji kluczowych parametrów modeli takich jak wybór długości ciągu użytego do konstrukcji modeli, współczynnika decymacji silnie nadpróbkowanego przebiegu w dziedzinie...
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Reduced order models of refined Yee´s cells.
PublicationArtykuł opisuje nowe podejście zwiększające dokładność metody różnic skończonych za pomocą lokalnego zagęszczenia siatki. Obszar niewiele większy niż pojedyncza komórka Yee jest pokrywany gęstą siatką, a jej makromodel jest stworzony metodą redukcji rzędu modelu równań stanu w dziedzinie częstotliwości. Makromodele są użyte w metodach różnic skończonych w dziedzinie częstotliwości i czasu całej struktury. Inaczej niż w przypadku...
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Efficient analysis of waveguide componets using a hybrid PEE-FDFD algorithm.
PublicationZaproponowano przyspieszenie analizy podzespołów falowodowych poprzez połączenie metody różnic skończonych w dziedzinie częstotliwości FDFD oraz rozwinięcia w funkcje własne PEE. Proponowane sformułowanie pozwala jawnie zdefiniować operator macierzowy dla zadanego problemu. Proponowana technika została zaprezentowana zarówno dla problemów własnych jak i układów z pobudzeniem.
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Scattering in junction by posts consisting of a segment of conducting cy linder.
PublicationWykorzystując zmodyfikowaną procedurę iteracyjną i metodę dopasowania rodzajów opracowano teorię rozpraszania fali elektromagnetycznej w złączu falowodowym na obiektach będących wycinkami metalowego cylindra. W wyniku analizy uzyskano wielorodzajową macierz rozproszenia złącza falowodowego zawierającego opisywane elementy. Zarówno zmiana położenia jak i obrót elementu w złączu powoduje zmianę jego parametrów elektrycznych....
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Efficient implementation of the Cauchy method for automated CAD-model construction.
PublicationW artykule przedstawiona została efektywna metoda konstrukcji wieloparametrycznych modeli układów mikrofalowych na podstawie wyników symulacji pełnofalowej. Algorytm wykorzystuje metodę najmniejszych kwadratów (TLS) do rozwiązania problemu interpolacyjnego i automatycznie dobiera rząd modelu.Przydatność i dokładność metody jest pokazana na przykładzie projektowania filtru z wykorzystaniem modeli trzech i pięciu zmiennych.
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Finite-difference analysis of a loaded hemispherical resonator
PublicationPrzedstawiono analizę osiowo symetrycznej struktury otwartego rezonatora he-misferycznego zawierającego warstwowe ośrodki dielektryczne. W analizie wy-korzystano metodę różnic skończonych w dziedzinie częstotliwości (FDFD). Wcelu osiągnięcia wysokiej dokładności obliczeń zastosowano zaawansowane me-tody modelowania warunków brzegowych i granicznych.
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A Note on Fractional Curl Operator
PublicationIn this letter, we demonstrate that the fractional curl operator, widely used in electromagnetics since 1998, is essentially a rotation operation of components of the complex Riemann–Silberstein vector representing the electromagnetic field. It occurs that after the wave decomposition into circular polarisations, the standard duality rotation with the angle depending on the fractional order is applied to the left-handed basis vector...
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Dual-Polarized Wideband Bandpass Metasurface-Based Filter
PublicationThis paper presents a novel metasurface-based bandpass filter. The structure is realized by simply patterning a double-sided AD250 substrate, and does not require any vias or insertion of lumped elements. The top layer is an annular- aperture-array with multiple inner conductors, whereas the bottom layer is a first-order Hilbert-curve array. FEM-based simulation results of the filter are obtained using HFSS. The experimental validation...
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Globalized Parametric Optimization of Microwave Passive Components Using Simplex-Based Surrogates
PublicationOptimization-based parameter adjustment involving full-wave electromagnetic (EM) simulation models is a crucial stage of present-day microwave design process. In fact, rigorous optimization is the only reliable mean permitting to simultaneously handle multiple geometry/material parameters, objectives, and constraints. Unfortunately, EM-driven design is a computationally intensive endeavor. While local tuning is usually manageable,...
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Compact Quasi-Elliptic-Type Inline Waveguide Bandpass Filters With Nonlinear Frequency-Variant Couplings
PublicationThis work presents the design techniques to synthesize a class of compact inline quasi-elliptic-type waveguide cavity bandpass filters based on novel nonlinear frequency-variant couplings (NFVCs). These highly dispersive frequency-variant couplings (FVCs) are realized by means of a pair of partial-height posts that are placed at the junctions between every two cavity resonators. Each NFVC produces a transmission pole in between...
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Revisiting Toroidal Dipolar Moment in Planar Metamaterial
PublicationThis article revisits the electric, magnetic, and toroidal dipolar moments in the metamaterial structure and presents the flatland design for generating a toroidal dipolar response for the electromagnetic plane wave at normal incidence. Based on the numerical analysis of the surface current, the electric field, the magnetic field, and the quantitative analysis of scattered power supported by the electromagnetic multipole theory,...
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Frequency-Variant Double-Zero Single-Pole Reactive Coupling Networks for Coupled-Resonator Microwave Bandpass Filters
PublicationIn 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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Design and experimental verification of multi-layer waveguide using pin/hole structure
PublicationThis study presents a novel technique for minimizing RF leakage in metallic hollow waveguides fabricated using the multilayer split-block method. By integrating a pin/hole wall into the split-block multilayers, a substantial reduction of RF leakage can be achieved while reducing the circuit size and mitigating the performance variations. To validate the proposed approach, a slot antenna fed by single ridge waveguide has been prototyped...
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Pareto Ranking Bisection Algorithm for Expedited Multi-Objective Optimization of Antenna Structures
PublicationThe purpose of this letter is introduction of a novel methodology for expedited multi-objective design of antenna structures. The key component of the presented approach is fast identification of the initial representation of the Pareto front (i.e., a set of design representing the best possible trade-offs between conflicting objectives) using a Pareto-ranking bisection algorithm. The algorithm finds a discrete set of Pareto-optimal...
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On Reduced-Cost Design-Oriented Constrained Surrogate Modeling of Antenna Structures
PublicationDesign of contemporary antenna structures heavily relies on full-wave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional data-driven...
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Zero-Pole Electromagnetic Optimization
PublicationA fast technique for the full-wave optimization of transmission or reflection properties of general linear timeinvariant high-frequency components is proposed. The method is based on the zeros and poles of the rational function representing the scattering parameters of the device being designed and it is the generalization of the technique developed for the design by optimization of microwave filters. The performance of the proposed...
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Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublicationThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...
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a novel modified star-triangular fractal (MSTF) monopole antenna for super-wideband applications
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a novel modified star-triangular fractal (MSTF) monopole antenna for super-wideband applications
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Genetic Hybrid Predictive Controller for Optimized Dissolved-Oxygen Tracking at Lower Control Level
PublicationA hierarchical two-level controller for dissolvedoxygenreference trajectory tracking in activated sludge processeshas been recently developed and successfully validated on a realwastewater treatment plant. The upper level control unit generatestrajectories of the desired airflows to be delivered by theaeration system to the aerobic zones of the biological reactor. Anonlinear model predictive control algorithm is applied to designthis...
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Synthesis of coupled lossy resonator filters.
PublicationA technique for fast synthesis of coupling matrix low-pass prototypes of generalized. Chebyshev bandpass filters with lossy resonators is presented in this letter. The coupling matrix is found by solving a nonlinear least squares problem based on zeros and poles of filter's transfer functions.
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A New Expression for the 3-D Dyadic FDTD-Compatible Green's Function Based on Multidimensional Z-Transform
PublicationIn this letter, a new analytic expression for the time-domain discrete Green's function (DGF) is derived for the 3-D finite-difference time-domain (FDTD) grid. The derivation employs the multidimensional Z-transform and the impulse response of the discretized scalar wave equation (i.e., scalar DGF). The derived DGF expression involves elementary functions only and requires the implementation of a single function in the multiple-precision...
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An Analysis of Multistrip Line Configuration on Elliptical Cylinder
PublicationA configuration of multistrip lines mounted on a multilayer dielectric coated elliptic cylinder is investigated in this paper. A full-wave analysis and a moment-method calculation are employed. The analysis is carried out considering the expansion of the field as a series of Mathieu functions. Both open and shielded lines are considered in the analysis. Propagation coefficients and characteristic impedances are calculated for the...
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Fast EM-driven size reduction of antenna structures by means of adjoint sensitivities and trust regions
PublicationIn this letter, a simple yet robust and computationally efficient optimization technique for explicit size reduction of antenna structures is presented. Our approach directly handles the antenna size as the main design objective, while ensuring satisfactory electrical performance by means of suitably defined penalty functions. For the sake of accuracy, the antenna structure is evaluated using high-fidelity EM simulation. In order...
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Structure and computationally-efficient simulation-driven design of compact UWB monopole antenna
PublicationIn this letter, a structure of a small ultra-wideband (UWB) monopole antenna, its design optimization procedure as well as experimental validation are presented. According to our approach, antenna compactness is achieved by means of a meander line for current path enlargement as well as the two parameterized slits providing additional degrees of freedom that help to ensure good impedance matching. For the sake of reliability, the...
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A Goal-Oriented Error Estimator for Reduced Basis Method Modeling of Microwave Devices
PublicationThis letter proposes a novel a-posteriori error estimator suitable for the reduced order modeling of microwave circuits. Unlike the existing error estimators based on impedance function residuals, the new one exploits the residual error associated with the computation of the scattering matrix. The estimator can be effectively used in the Reduced Basis Method (RBM) to automatically generate reduced-order models. The results of numerical...
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Rapid multi-objective simulation-driven design of compact microwave circuits
PublicationA 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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Generalized Chebyshev Bandpass Filters With Frequency-Dependent Couplings Based on Stubs
PublicationThis paper presents an accurate synthesis method for inline and cross-coupled generalized Chebyshev bandpass filters with frequency-dependent couplings implemented via open and short stubs. The technique involves the synthesis of a lumped-element prototy pe in the form of a coupling matrix with a frequency-dependent term and the conversion of this prototype to a distributed-element mode l composed of sections of TEM lines. This...
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A Trisection Filter Design With Negative Slope of Frequency-Dependent Crosscoupling Implemented in Substrate Integrated Waveguide (SIW)
PublicationThis 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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A Novel Coupling Matrix Synthesis Technique for Generalized Chebyshev Filters With Resonant Source–Load Connection
PublicationThis paper reports a novel synthesis method for microwave bandpass filters with resonant source–load connection. In effect, a network realizing N+1 transmission zeros (where N is the number of reflection zeros) is obtained. The method is based on a prototype transversal coupling matrix (N+2, N+2) with source and load connected by a resonant circuit formed by a capacitor in parallel with a frequency-invariant susceptance. To complement...
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Hybrid Technique Combining the FDTD Method and Its Convolution Formulation Based on the Discrete Green's Function
PublicationIn this letter, a technique combining the finite-difference time-domain (FDTD) method and its formulation based on the discrete Green's function (DGF) is presented. The hybrid method is applicable to inhomogeneous dielectric structures that are mutually coupled with wire antennas. The method employs the surface equivalence theorem in the discrete domain to separate the problem into a dielectric domain simulated using the FDTD method...
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A Linear Phase Filter in Quadruplet Topology With Frequency-Dependent Couplings
PublicationThis letter presents a design of a linear phase microwave bandpass filter. The filter is composed of four resonators arranged in the quadruplet topology. Making the cross and one direct coupling dispersive gives additional design flexibility. The first advantage of using frequency-dependent couplings is the possibility to chose an arbitrary location of a pair of complex transmission zeros (TZs) in the s-domain. The second one is...
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Fast clutter cancellation for noise radars via waveform design
PublicationCanceling clutter is an important, but very expensive part of signal processing in noise radars. It is shown that considerable improvements can be made to a simple least squares canceler if minor constraints are imposed onto noise waveform. Using a combination of FPGA and CPU, the proposed scheme is capable of canceling both stationary clutter and moving targets in real-time, even for high sampling rates.
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GPU Acceleration of Multilevel Solvers for Analysis of Microwave Components With Finite Element Method
PublicationThe 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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Soft- and hard-decision multiple-model estimators for air traffic control
PublicationAnalizuje się problem śledzenia samolotów cywilnych manewrowania w zapewnianiu kontroli ruchu lotniczego (ATC) systemów za pomocą wielomodelowej (MM) estymacji stanu. Budując odpowiedni zestaw modeli manewrowania można opisać, jak różne manewry wpływają na proces oceny stanu wykonywany przez filtr Kalmana (KF) w oparciu o model ruchu bezmanerwowego. Metodologia ta prowadzi do podsystemu diagnostycznego, który wspiera estymator...
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A Novel Modal Technique for Time and Frequency Domain Analysis of Waveguide Components
PublicationW pracy zaprezentowano, nową i szybką metodę analizy komponentów falowodowych. Metoda opiera się na kombinacji metody różnic skończonych, metody dekompozycji dziedziny obliczeniowej, redukcji rzędu modelu oraz dyskretnych rozwinięć funkcyjnych. Przedstawiona technika pozwala na skrócenie czasu analizy układu nawet o dwa rzędy wielkości w stosunku do poprzednich algorytmów.
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A New Type of Macro-Elements for Efficient Two-Dimensional FEM Analysis
PublicationThis letter deals with a model order reduction technique applicable for driven and eigenvalue problems solved using the finite element method (FEM). It allows one to efficiently compute electromagnetic parameters of structures comprising small features that require strong local mesh refinement. The subdomains of very fine mesh are separated from the global domain as so called macro-elements that undergo model reduction. The macro-elements...
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Design of Microwave Lossy Filter Based on Substrate Integrated Waveguide (SIW)
PublicationIn this letter, we propose a lossy three-pole Chebyshev filter centered at 5.15 GHz, based on the substrate integrated waveguide (SIW) with scattering characteristics shifted down by 5.68 dB. The filter is composed of three directly coupled SIW cavities with three lossy couplings between nonadjacent resonators. These additional couplings are realized using mixed coupled slot and microstrip lines connected with metal electrode leadless...
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Tuning a Hybrid GPU-CPU V-Cycle Multilevel Preconditioner for Solving Large Real and Complex Systems of FEM Equations
PublicationThis letter presents techniques for tuning an accelerated preconditioned conjugate gradient solver with a multilevel preconditioner. The solver is optimized for a fast solution of sparse systems of equations arising in computational electromagnetics in a finite element method using higher-order elements. The goal of the tuning is to increase the throughput while at the same time reducing the memory requirements in order to allow...
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Analytical Expression for the Time-Domain Discrete Green's Function of a Plane Wave Propagating in the 2-D FDTD Grid
PublicationIn this letter, a new closed-form expression for the time-domain discrete Green's function (DGF) of a plane wave propagating in the 2-D finite-difference time-domain (FDTD) grid is derived. For the sake of its verification, the time-domain implementation of the analytic field propagator (AFP) technique was developed for the plane wave injection in 2-D total-field/scattered-field (TFSF) FDTD simulations. Such an implementation of...
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Expedited design of microstrip antenna subarrays using surrogate-based optimization
PublicationComputationally efficient simulation-driven design of microstrip antenna subarrays is presented. The proposed design approach aims at simultaneous adjustment of all relevant geometry parameters of the subarray, which allows us to take into account the effect of the feeding network on the subarray radiation pattern (in particular, the side lobe level, SLL). In order to handle a large number of variables involved in the design process,...
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Rapid EM-Driven Design of Compact RF Circuits By Means of Nested Space Mapping
PublicationA methodology for rapid design of RF circuits constituted by compact microstrip resonant-cells (CMRCs) is presented. Our approach exploits nested space mapping (NSM) technology, where the inner SM layer is used to correct the equivalent circuit model at the CMRC level, whereas the outer layer enhances the coarse model of the entire structure under design. We demonstrate that NSM dramatically improves performance of surrogate-based...
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A Self-Equalized Waveguide Filter With Frequency-Dependent (Resonant) Couplings
PublicationThis letter presents a design of a fifth-order linear phase filter with frequency-dependent couplings. The filter is composed of a triplet that is directly coupled to two resonators at the input and output. To provide group delay flattening a cross-coupling in the trisection has a strongly dispersive character with a negative slope parameter. To achieve this, an E-plane stub with a septum was used. To further improve the filter...
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Expedited EM-driven multi-objective antenna design in highly-dimensional parameter spaces
PublicationA technique for low-cost multi-objective optimization of antennas in highly-dimensional parameter spaces is presented. The optimization procedure is expedited by exploiting fast surrogate models, including coarse-discretization EM antenna simulations and response surface approximations (RSA). The latter is utilized to yield an initial set of Pareto non-dominated designs which are further refined using response correction methods....
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Dimensional Synthesis of Coupled-Resonator Pseudoelliptic Microwave Bandpass Filters with Constant and Dispersive Couplings
PublicationIn this paper, we propose a novel technique for the dimensional synthesis of coupled-resonator pseudoelliptic microwave filters with constant and dispersive couplings. The proposed technique is based on numerical simulations of small structures, involving up to two adjacent resonators, and it accounts for a loading effect from other resonators by replacing them with terminations coupled through appropriately scaled inverters. The...