Modeling of a millimeter wave planar Schottky diode using both improved equivalent circuit model and 3D-EM model

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

Mode matching method and equivalent circuit method are the two main waveguide filter design methods. The mode matching method have well calculation accuracy, especially when the waveguide size is relatively large compared with operating wavelength, but this method does not provide physical insights, therefore traditional filter design theories and methods cannot be applied. However, in most of the engineering applications, the size of the waveguide filter is not large to prevent higher-order modes from affecting the performance of the entire system. Under this condition, the equivalent circuit, providing physical insight, and efficient with acceptable accuracy, becomes the preferred method when designing waveguide filters. Unfortunately, the equivalent circuit of the waveguide filter that has been established so far is realized by connecting multiple Y-parameter elements with transmission lines. This method does not show the internal structure of the waveguide filter cavity, so in fact it cannot provide physical insight. Moreover, compared with the mode matching method, the reduction of the calculation amount is also very limited. This paper gives the complete equivalent circuit model of the waveguide filter with analytical expressions for the first time. The establishing process of equivalent circuit represents by capacitors and inductors are given in detail by taking circular waveguide filter excited by TM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</inf> mode as an example. The effectiveness of the proposed method is verified by finite element simulations and experiments.

A comparison between the equivalent circuit model and moment method was done. Numerical results were obtained with the equivalent circuit model using Matlab routines and with moment method using the Ansoft Design <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¿</sup> software. Experimental results obtained from literature were compared with numerical results. A good agreement was observed. Two dual band geometries were considered: the Jerusalem cross and the double square loop. The parameters used to comparison were analytical complexity, accurate, and computational effort. For this last parameter and considering the worst case, the equivalent circuit method was run in 55 ms, while the method of moments took around 4 hours.

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.

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 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.

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

The growing use of electric vehicles has led to an ever-increasing demand for efficient and reliable management systems to control the behavior of lithium-ion batteries, especially with respect to heat generation and state-of-charge. Understanding these patterns constitutes a major new challenge for these batteries, as remaining ignorant of their behavior can result in decreased performance, shorter service life and even safety dangers. This review provides an overview of the different modeling techniques applied to simulate battery behavior. Different methods using equivalent electrical circuit models are discussed, covering both simple battery models and more complex equivalent electrical circuit models, with a focus on the 2RC-Thévenin circuit model. In this context, parameter approach methods for these systems are reviewed. In addition, laboratory tests are run to identify the various model parameters for a lithium-ion battery. This comprehensive study is designed to guide scientists and engineers in the selection and use of suitable tools for state-of-charge and battery health studies.

The corrosion of reinforcement has always been a problem to be solved in the field of architecture. In this paper, the corrosion characteristics of chromium alloy steel under different pH conditions are studied. The impedance characteristics and equivalent circuit are predicted by neural network model. First of all, in simulated pore solution with different pH values, the characteristics of Nyquist impedance spectroscopy of the whole chromium alloy under passivation stage and the damaged passivation film of reinforcing bars under initial corrosion stage have been found. Then, according to the difference of impedance characteristics under different pH values, different equivalent circuits have been established and [Formula: see text] values of different equivalent circuits under different chloride ion concentration have been calculated. By fitting the electrochemical parameters of the equivalent circuit with [Formula: see text] values, the equivalent circuit model which can be predicted by neural network has good consistency with the equivalent circuit which can be predicted by [Formula: see text] values.

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.

Several methods of device and circuit modelling are reviewed, followed by a detailed outline of state-of-the-art equivalent circuit and physical modeling techniques applicable to both device and circuit design. It is noted that the requirement for CAD (computer-aided design) utilities which extend available linear design techniques into the large-signal regime is being met by both equivalent circuit and physical device models, coupled with powerful algorithms such as the harmonic balance technique. The advent of fast physical device models allows the designer to optimize both devices and circuits based on the actual device structure, without resorting to electrical measurements at the design stage. This is particularly important in the design of integrated circuits, where it is essential to minimize the cost of the design-fabrication cycle.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Presently, there are mainly two problems that prevent Electric Vehicles (EVs) from becoming popular against the Internal Combustion Engine Vehicles (ICEVs), namely: short range and too long to recharge the battery pack of the EV. Due to this, battery development is a crucial aspect to improve the performance of EVs. This progress requires dependable computer aided designs to model the characteristics of a battery accurately and reliably. This paper uses Power Systems Computer Aided Design (PSCAD) to create an equivalent runtime circuit model to observe the qualities of the Lithium Iron Phosphate battery cell under discharge at different temperatures. The model is a 3-R-C branch runtime equivalent circuit model. In order to find the fixed parameters of the circuit, MATLAB was used to implement basic current voltage characteristics. 3-D tables have been used in PSCAD to implement the State of Charge (SOC) and temperature dependent circuit parameters of the model. Once the simulations for all temperatures were completed, the average marginal error between measured and simulated terminal voltage came to be 2.1%, therefore making PSCAD an accurate simulation tool for modeling equivalent circuits of different batteries.

A different parameter extraction approach based on zero immittances for composite right/left-handed (CRLH) structure is presented. For lossless unit cell equivalent circuit model, LC parameters of series and parallel branches are extracted according to series resonance frequency and parallel resonance frequency, respectively. This approach can be applied to symmetric and unbalanced CRLH structures. The parameter extraction procedure is provided and validated by T-type unit cell model. The responses of distributed prototype and extracted equivalent LC circuit model are in good agreement. The equivalent circuit modeling can improve the degree of freedom in the CRLH TLs design. This parameter extraction method provides an effective and straightforward way in CRLH metamaterials design and applications in telecommunication systems.

Low-frequency experimental method for measuring the electric double-layer capacitances of multi-cell electrolysis stacks based on equivalent circuit model

This study analyzes an underwater inductive wireless power transfer (UIWPT) to be used in offshore vehicles. Fixating on inadvertent eddy current losses (ECLs), this study offers an approach to tackle this concern based on the optimal selection of main design parameters of Archimedean magnetic coils. An accurate analytical electromagnetic field model is derived for directly calculating ECLs, and based on the ECL model, the main design parameters of coils are selected. The electrical fundamental components of coils are calculated as a function of the selected design parameters. A numerical metaheuristic optimization method along with the formulation of a multi-objective function and inequality constraints is utilized to estimate the selected parameters of coils. This function addresses various design objectives simultaneously, considering the water medium and inequality constraints. For optimization purposes, an electrical equivalent circuit model is derived, considering the ECLs impact by reflecting these losses in the equivalent circuit model. The ECL model is verified through Finite Element Analysis (FEA). Finally, a laboratory scale setup is developed and UIWPT experiments are conducted to validate the equivalent circuit and analytical modeling, the calculation of components, and the simulation study.