構 裝 接 線 與 接 腳 的 等 效 電 路 模 型 擷 取與 分 析

This paper presents an investigation of both electromagnetic wave model and equivalent circuit model for microstrip patch antenna (MPA) with rectangular defected ground plane structure (RDGS). The objective of the proposed design is to reduce antenna size from Wi-Fi wireless band to the Bluetooth band. The first part of the paper describes the electromagnetic wave modeling using the High Frequency Structure Simulator (HFSSreg) software to study the effect of RDGS on antenna resonant frequency. An optimization tool together with curve fitting were then used to formulate an approximate equation that describes the identified trends from the simulations. Second part is focused on estimating, using the Advanced Designing System (ADS) software the parameters of an equivalent circuit model for MPA with RDGS. The developed equivalent circuit consists of lumped elements for both MPA and RDGS structure and also include representation of the electrical and the magnetic coupling between rectangular grounded slot and MPA. Optimum values of the equivalent circuit elements were determined, and the overall simulation results were confirmed experimentally.

This paper presents a new metamaterial, based on SRR structure and systematically investigate the various properties of the metamaterial structure. The resonant frequency of the proposed metamaterial structure is first estimated using its equivalent circuit model and the estimated value thus obtained is then compared with the values obtained by High Frequency Structure Simulator (HFSS) simulations. The negative refraction in the unit cell is demonstrated by estimating the negative ε and negative µ on placing the unit cell in a waveguide with well defined PEC/PMC boundary conditions. Finally the unit cells are combined to form linear 2D array topology.   Key words: Metamaterial, split ring resonators (SRR), equivalent circuit model, high frequency structure simulator (HFSS). &nbsp

This paper proposed a novel hybrid axial magnetic bearing (HAMB) for a vertical system, which can produce a unidirectional magnetic force. The principle of the new HAMB is analyzed. When the rotor is suspended in the equilibrium position, the bias force offsets the gravity of the rotor and the current is zero, which can reduce the copper loss. According to the magnetic field distribution, an equivalent magnetic circuit is established. Based on the analytical model, the curve of force-current, curve of force-displacement and bearing capacity are calculated. The results of analytical are consistent with the ones of the finite element method (FEM).Index Terms—Hybrid, axial magnetic bearing, magnetic circuit, finite element.I. IntroductionMagnetic bearings (MBs) are widely used in high-speed rotating machinery, such as compressors, flywheel energy storages for the merits of contactless property and long life[1]. To reduce copper loss, hybrid MB has become the research feature combing the characteristics of active MB and passive MB [2]-[4].Several axial MB are significant in vertical levitation rotor systems. A novel hybrid axial MB is proposed in [5], which reduces the reluctance of the control path and power loss of axial MB and through constructing the second air gap. In [6], an improved magnetic circuit model is introduced for a novel axial hybrid MB, which provides a reference for the MB design. In [7], an equivalent magnetic circuit with the conformal mapping method and Laplace’s equation is developed for axial MB with multiple air gaps. The results of analysis are consistent with the ones of finite element analysis.In this paper, a novel hybrid axial magnetic bearing (HRMB) is proposed for the vertical system, which produces a unidirectional electromagnetic force to replace the traditional bidirectional force. There is no need for the current to control the MB when the rotor is in the equilibrium position, which reduces the copper loss greatly. Then, the equivalent magnetic circuit method is adopted to analyze the performances of the HRMB. Ultimately, the accuracy of the analytical model is validated by the finite element method (FEM).II. Principle of Hybrid Axial Magnetic BearingA. Principle of HAMBThe structure of HAMB is shown in Fig.1. The blue solid line represents the bias flux, and the red dotted line represents the control flux.B. Magnetic circuit modelThe equivalent magnetic circuit models of the bias flux and control flux are established.III. Analysis of HRMBThe variation of force with current and displacement can be obtained in Fig.2. The analytical results are in agreement with the results of FEM. The bias force and maximal force are calculated and compared with the finite element method. The margin of error is within 10%.IV. ConclusionA novel hybrid axial magnetic bearing is proposed in this paper and the principle of HAMB is analyzed. The structure has low copper loss when the rotor is stable in the suspension position. According to magnetic field distribution, an equivalent magnetic circuit is established. The curve of force-current, curve of force-displacement and bearing capacity are calculated by analytical and FEM respectively. The accuracy of the analytical model is confirmed by FEM. **

Purpose The purpose of this paper is to present the results of a particle swarm optimization (PSO) method applied in the design of a square-loop frequency selective surface (FSS) via the equivalent circuit model (ECM), considering the dielectric effective permittivity as a variable in the optimization problem. Design/methodology/approach In the optimization process considered, besides the FSS square loop geometric parameters, the thickness and relative permittivity of dielectric material used as support are included as variables in the search space, using for this a model of dielectric effective permittivity introduced by the authors in a previous work. Findings Square loops were designed and the obtained results were compared with designs reported in literature for applications in wireless local area network and long-term evolution 4G systems. The low computational cost is remarkable as well as the acceptable accuracy obtained with the proposed approach. The PSO method results were implemented with the ECM and compared with those obtained via Ansys – high frequency structure simulator commercial software simulations. Originality/value The lack of a model of dielectric effective permittivity for the ECM causes a restricted search space in the stochastic FSS design process limited to only geometric parameters, as it is reported in the available literature. The proposed approach simplifies and makes more flexible the design process, and allows guiding the FSS design to unit cell surface and/or dielectric thickness of small dimensions.

Characterization of high-power lithium-ion batteries by electrochemical impedance spectroscopy. II: Modelling

A general equivalent model for slow-wave structure is established in this paper, if the unit cell of the periodic slow-wave structures is represented by a three-port network and the parameters of the equivalent model are determined by a high frequency structural simulator. In this method, there is no need to find a complicated equivalent circuit, and the fields in the tunnels can be calculated by the high frequency software directly. Therefore, the three-port network model is simpler than the analytic method and no more complex than the common equivalent circuit model. A one-dimensional nonlinear beam-wave interaction theory suitable for the folded-waveguide traveling wave tubes (TWTs) is accomplished based on the three-port network model. And a one-dimensional nonlinear beam-wave interaction code, which complies with the MATLAB language, is used to simulate a folded-waveguide TWT. The difference between the results obtained from the code and the experimental data is less than 10%. This theory can be used in the design of novel folded-waveguide TWTs and research on nonlinear simulations.

ABSTRACTAn effective rigorous 3‐D optical modeling of thin‐film silicon solar cells based on finite element method (FEM) is presented. The simulation of a flat single junction thin‐film silicon solar cell on thick glass (i.e., superstrate configuration) is used to validate a commercial FEM‐based package, the High Frequency Structure Simulator (HFSS). The results are compared with those of the reference software, Advanced Semiconductor Analysis (ASA) program, proving that the HFSS is capable of correctly handling glass as an incident material within very timely, short, and numerically stable calculations. By using the HFSS, we simulated single junction thin‐film silicon solar cells on glass substrates textured with one‐dimensional (1‐D) and two‐dimensional (2‐D) trapezoid‐shaped diffraction gratings. The correctness of the computed results, with respect to an actual device, is discussed, and the impact of different polarizations on spectral response and optical losses is examined. From the simulations carried out, optimal combinations for period and height in both 1‐D and 2‐D grating configurations can be indicated, leading to short‐circuit current percentage increase with respect to a flat cell of, respectively, 25.46% and 32.53%. With very limited computer memory usage and computational time in the order of tens of minutes for a single simulation, we promote the usage of 3‐D FEM as a rigorous and efficient way to simulate thin‐film silicon solar cells. Copyright © 2012 John Wiley & Sons, Ltd.

Magnitude-phase equivalent circuit and steady-state power-angle characteristic analysis of DFIG

This paper reports the design and evaluation of a multi-electrode design that improves upon the statistical significance and spatial resolution of cellular impedance data measured using commercial electric cell-substrate impedance sensing (ECIS) systems. By evaluating cellular impedance using eight independent sensing electrodes, position-dependent impedance measurements can be recorded across the device and compare commonly used equivalent circuit and mathematical models for extraction of cell parameters. Data from the 8-electrode device was compared to data taken from commercial electric cell-substrate impedance sensing (ECIS) system by deriving a relationship between equivalent circuit and mathematically modelled parameters. The impedance systems were evaluated and compared by investigating the effects of arsenic trioxide (As2O3), a well-established chemotherapeutic agent, on ovarian cancer cells. Impedance spectroscopy, a non-destructive, label-free technique, was used to continuously measure the frequency-dependent cellular properties, without adversely affecting the cells. The importance of multiple measurements within a cell culture was demonstrated; and the data illustrated that the non-uniform response of cells within a culture required redundant measurements in order to obtain statistically significant data, especially for drug discovery applications. Also, a correlation between equivalent circuit modelling and mathematically modelled parameters was derived, allowing data to be compared across different modelling techniques.

The need for flexible energy storage devices for advanced technologies has encouraged researchers to focus on environmental‐friendly biopolymers. In this work, chitosan (CS) and potato starch (PS) biopolymers are blended to prepare proton conducting solid electrolytes. Based on the X‐ray diffraction (XRD) inspection, the most amorphous blended film with the lowest crystallinity degree was selected to prepare polymer electrolytes. The variation in Fourier‐transform infrared spectroscopy (FTIR) bands were used to investigate the occurrence of interactions among the ammonium thiocyanate (NH4SCN) salt and CS:PS polymer blends. The experimental results of electrochemical impedance spectroscopy (EIS) were simulated with electrical equivalent circuit (EEC) modeling to determine the circuit elements. The highest value of S cm−1 was recorded for the sample included 40 wt.% of dopant salt. The dielectric analyses were helpful in separating the regions ascribed to electrode and molecular polarizations. The combination of circuit elements achieved from the EEC modeling and Koops phenomenological interpretation is used to understand the behavior of the loss tangent (tanδ) pattern. The AC conductivity pattern followed Jonscher's power law. The relaxation dynamics interrelated with ions is explained using electric modulus approaches. The peaks hidden in the dielectric loss () spectra, were manifested in the imaginary part of electric modulus () pattern. The ‐ patterns were used to shed light on the coupling between ionic motion and polymer chain dynamics.

A simple analysis technique for a concept in frequency selective surfaces (FSSs) basis from Babinet's principle, of two closely coupled conducting elements is presented. A layer of conducting patch elements and a layer of slot elements are designed on either side of a substrate, named as complementary FSS (CFSS). An equivalent circuit (EC) model in conjunction with transmission line (TL) model is employed to analyze the response of the structure. This method can predict the scattering parameters with high accuracy at a normal and oblique angle of incidence for both parallel and perpendicular polarizations. A parametric study of CFSS array aimed at their EC model optimization is presented. The CFSS exhibits a highly stable passband for normal and oblique incidences. The validity of the proposed method is verified with commercial simulation software package. It is observed that the results obtained by both methods are very good in agreement.

This project concerns the use of an electromagnetic sensor for the detection of leaks/cracks in water pipes. As old metal pipes corrode they start to become brittle, resulting in the potential for cracks to appear in the pipes. In addition corrosion can build up resulting in a restricted flow of water in the pipe. Using an electromagnetic (EM) wave sensor to monitor the signal reflected from the pipes in real time, provides the necessary information to determine where a leak in the pipe has occurred. Analysis of the reflected signal can provide the operator with information about the condition and position of a leak within the pipe. This is the first time research has been carried using EM waves for leak detection in water pipelines. This project involves the design and construction of an EM sensor operating at frequencies in the range of 240MHz to 560MHz, and at a power of OdBm. The sensor is launched into the water pipeline through any existing hydrant and is moved along the pipeline to check for leaks. The simulation software High Frequency Structure Simulator (HFSS) was used to model the pipe section as a circular waveguide cavity, and also for antenna simulation. The monopole and loop antenna were designed to determine the best antenna for this project. The printed circuit board (PCB) design package Eagle was used to provide the surface mount layout for the sensor, and the PCB board was fabricated by using a computer numerical control (CNC) routing machine. Finally the graphical interface package LabVIEW was used to control the frequency sweep for the sensor and to capture the data from the sensor. Based on the findings of this project, the EM wave sensor could be used to determine a leak up to a 0.9 correlation limit using low cost RF electronic devices.

This paper proposes a novel ultra-wideband (UWB) bandpass filter (BPF) with a shielded multilayered (ML) structure. Compared with recently proposed planar UWB BPFs based on a microstrip line configuration, this filter can be made more compact and can reduce the interference to other circuit components. We have studied scattering characteristics of the filter by a finite element method (FEM), an equivalent circuit analysis and experiments. In the FEM analysis, this filter shows a UWB performance from 1.61 GHz to 4.11 GHz, which bandwidth corresponds to RBW/sub -3dB/ = 87.4%. In this passband, the maximum ripple is 0.86 dB and the minimum insertion loss is 0.11 dB. These theoretical predictions show good agreement with the experimental results. Further, a measured group delay is moderate around the center passband with a typical value of 0.4 ns. An equivalent circuit model is also developed to gain a useful insight into the filter mechanism.

This paper presents a switchable perfect absorber/reflector in S band using a PIN diode integrated active frequency selective surface (AFSS). It is numerically demonstrated that the AFSS shows over 99% absorptivity at 3.5 GHz when the diode is forward biased, whiles reflects over 99% incident power when the diode is inversed biased. An equivalent circuit (EC) model is further developed to characterize the AFSS's switchable electromagnetic performance and aim at model optimization. The empirical formulas and curve fitting technology have been employed to get the lumped element parameters in the EC model. Special considerations are given to physical attributes, including the dielectric permittivity and thickness of the substrate. The consistency of the electromagnetic simulations and EC analysis demonstrates the high accuracy of the developed EC model.

Through-silicon vias (TSVs) are essential for 3D integrated circuits (ICs) and advanced chiplet packaging. The semiconductor industry is transitioning toward 3D ICs, chiplets, and system-in-package (SiP) solutions due to the slowdown of Moore’s Law and limitations in conventional silicon scaling. In this paper, we propose an optimized TSV architecture for high-frequency transmission to enhance its suitability for 6G communication chips, and develop a comprehensive equivalent circuit model for fault-free and faulty TSVs. This model accounts for open-circuit and short-circuit fault conditions while considering the effects of higher frequencies, substrate type, doping concentration, and adjacent layers. At the physical level, the TSVs are simulated using the Ansys High-Frequency Structure Simulator (HFSS), and the equivalent circuits are designed using the Cadence Virtuoso tool. An experimental evaluation is also conducted to validate the physical design. We position the TSVs in a pattern of ground-signal-ground (G-S-G) to reduce the effective inductance of the signal TSV, thereby minimizing inductive reactance at ultra-high frequencies. Consequently, the reflection coefficient remains below -10 dB across the frequency range of 0.1 to 146.3 GHz. Furthermore, we compare simulation outcomes from HFSS and Cadence for both fault-free and faulty TSVs under varying operating conditions. Additionally, the parasitic circuit components are characterized through extensive theoretical derivations for in-depth circuit verification. Collectively, the rigorous analysis, experimental validation, and thorough investigation of the proposed design and its equivalent circuit demonstrate their potential for use in creating datasets for a fault prediction machine learning model.