CRLH Transmission Lines for Telecommunications: Fast and Effective Modeling

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.

Fixed-frequency beam scanning leaky-wave antennas (LWAs) that can scan their main beam over a specific frequency band are highly desired for future wireless communication systems. A composite right-/left-handed (CRLH) LWA is developed in this article that facilitates fixed-frequency continuous beam scanning over a wide operational frequency band. A variation of a simple single-layer nonreconfigurable frequency-based continuous beam scanning CRLH LWA is considered first. Its dispersion properties are approximately investigated using an equivalent circuit model. It is reported how two groups of varactor diodes can be incorporated into its basic circuit model to electronically control its dispersion behavior. An optimized reconfigurable CRLH LWA with practical dc biasing lines is then realized from this nonreconfigurable design. Fixed-frequency continuous beam scanning, from backward to forward directions through broadside, is reported over a wide operational frequency band. Simulations predict that the antenna can operate from 4.75 to 5.25 GHz with the main beam being continuously scannable at each frequency point. A prototype was fabricated, assembled, and tested. The measured results confirm its simulated performance characteristics.

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

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

A compact beam scanning substrate integrated waveguide (SIW) composite right/left-handed (CRLH) leaky wave antenna (LWA) is presented in this paper. The dispersive behavior of the unit cell is discussed and compared with its equivalent circuit model. A SIW CRLH LWA that composed of 15-unit cells is designed and its transient e-field distribution for the left-handed, right-handed and transition frequencies are demonstrated by performing a full-wave simulation using CST microwave studio. The proposed antenna is designed to operate within the S-band frequency range exhibiting a continuous backfire to endfire beam scanning of 133 degrees from -68 degree at 2.05GHz up to +65 degree at 3.25GHz for the backward and forward wave radiations, respectively. The numerical results show a relatively high gain with a maximum gain of 8.6dBi at 2.55GHz and low cross-polarization for the entire band.

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.

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.

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.

This paper presents a novel design concept for near-field wireless power transfer (WPT) systems that leverages the seamless integration of metamaterials (MTMs) into slotted resonators. This approach enhances magnetic field ( $$\textbf{B}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> </mml:math> ) distribution, strengthens evanescent wave coupling, and hence improves overall WPT performance. An MTM structure exhibiting negative permeability at the operating frequency of 433 MHz was designed and incorporated into a square-slot-based resonator. Electromagnetic (EM) analysis revealed increased current density and subsequently enlarged $$\textbf{B}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> </mml:math> around the resonator. Additionally, impedance matching, key parameter extraction, and equivalent circuit (EC) modeling were performed using the effective J-inverter method. The developed WPT system, with compact dimensions of 30 $$\times$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>×</mml:mo> </mml:math> 30 $$^{\text {2}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mtext>2</mml:mtext> </mml:mmultiscripts> </mml:math> , achieved a power transfer efficiency of 82% at 33 mm. The design was experimentally validated, showing excellent agreement among EM simulations, EC modeling, and measurement results. Finally, performance comparison with other reported systems confirmed the superiority and practical effectiveness of the proposed design in enabling compact and highly efficient WPT 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.

IGBT is the key component of electric vehicle motor control system. In order to control IGBT and motor accurately and effectively, the structure of MOSFET and N-IGBT is given based on semiconductor principle. The four-layer PNPN structure of IGBT is analyzed. The equivalent circuit model of IGBT based on MOSFET, PNP and NPN transistor is established. Combining with Infineon IGBT chip and its application data, the collector current transmission characteristic curves under different gate source voltages and environment temperature are given. The simulation method of the same characteristic curves can be obtained by setting IGBT micro-variable equivalent circuit model parameters using Q3D and Simplorer. The model parameters such as parasitic capacitance, parasitic inductance, junction resistance and so on of the IGBT chip are determined and extracted. Thus the accurate model of IGBT chip is established. The simulation results show that the modeling and parameters extraction methods can effectively extract the precise parameters of IGBT, and can provide precise data for the analysis and establishment of the equivalent circuit model of IGBT.

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.

A composite right/left‐handed (CRLH) extended equivalent circuit (EEC) FDTD method with a stability criterion based on a Liapunov discrete energy function is presented and applied to investigate several transient and refractive phenomena occurring at the interface between a CRLH metamaterial (MTM) and a purely right‐handed (PRH) structure. This formulation consists in an extension of the equivalent circuit (EC) Yee scheme including a left‐handed (LH) series capacitance and shunt inductance in addition to the canonical right‐handed (RH) series inductance and shunt capacitance, so as to model general CRLH transmission line (TL) MTMs. This CRLH‐EEC FDTD scheme is shown to represent a convenient numerical scheme, with remarkable formulation compactness and high computational efficiency, for the analysis of any type of MTM structure. Moreover, this scheme, coupled with a Y‐matrix representation of the EEC Yee cell, is shown to rigorously restore the dispersion/attenuation relation of CRLH MTMs. Transient solutions for the propagation of a modulated Gaussian pulse through a PRH–CRLH interface highlights interesting effects such as space‐domain compression, infinite phase velocity modulation and the well‐known backward wave effect. Frequency‐domain analysis of the fields radiated by dipoles through the Veselago–Pendry lens shows how focusing is affected both qualitatively and quantitatively by the orientation of the dipoles. Copyright © 2006 John Wiley &amp; Sons, Ltd.

This letter presents the design of a new efficient double negative metamaterial antennas. The design of the unit cell of these antennas is based on the composite right/left-handed (CRLH) transmission line model. The zeroth-order resonance of this kind of antennas depends mainly on the equivalent circuit of the unit cell and provides the opportunity to design the antenna with very small electrical size. The previous published results show that the conventional CRLH mushroom radiator suffers from narrow bandwidth and low gain. In this letter, we introduce a new method of design of CRLH metamaterial antennas to tackle the above problem using two layers of CRLH mushroom structure. The upper layer of the CRLH is used to reduce the reactance of the small antenna and to improve the matching between the antenna and the feeding line. The results at the zeroth-order resonance show improvements in the antenna gain and bandwidth by introducing the upper layer. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2224–2229, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27078