Strip Conductor Research Articles

Parametric Effects of Resistance Spot Welding between Li-ion Cylindrical Battery Cell and Nickel Conductor Strip

The resistance spot welding method is commonly used in the cylindrical battery packing because of production costs. However, its quality is lower than other welding methods. To improve the quality, three parameters which are slot geometries of nickel conductor strip, welding position and welding position sequence are studied in this paper using both simulations and experimental methods. According to different slot geometries, if the slot length is longer than the positive battery terminal diameter, the high welding current flows through the welding point. To weld different positions, it results in structural deformation of the positive battery terminal which directly affects the contact pressure. As different welding position sequences for three welding spots on the positive battery terminal, it is found that the sequence starting at the middle is better than which from the sides. In conclusion, these parameters can be used to improve the welding quality; nevertheless, there are still other parameters which will be studied in the future.

Microstrip transmission line model‐fitting approach for characterization of textile materials as dielectrics and conductors for wearable electronics

AbstractCharacterization of unconventional materials is essential in the field of microwave engineering. In this study, we present a method for the microwave characterization of conductive and nonconductive textile materials. Our approach is based on fitting the material parameters of a numerical microstrip transmission line model so that the simulated signal transmission properties match with the data we measure from implemented test lines. Unlike many conventional test structures, such as cavity resonators and waveguides, microstrip lines can be readily manufactured in textile technology with rather relaxed tolerances in the fabrication process. In addition, our method provides estimates for all three key material parameters: frequency‐dependent relative permittivity and loss tangent of the nonconductive line substrate and the bulk conductivity of the strip conductor. For validation, we have characterized conventional microwave laminates and compared the data with the datasheets and literature and used our parameter estimates for the textile materials to optimize fully textile‐based low‐pass filters. Overall, the results confirm the applicability of our method for microwave engineering with textile materials.

Selective Excitation of the Microwave Sommerfeld—Zenneck Surface Wave on a Conductive Strip

Surface electromagnetic waves (SEWs) on imperfect conductors proposed by A. Sommerfeld and J. Zenneck in the early 20th century have remained unrecognized by academic science for almost a hundred years due to a regrettable misunderstanding of theorists and unsolved radio communication problems. Recognition could have come much earlier if radiophysicists had been able to apply excitation of SEWs in the centimeter range of microwaves, generation of which became possible in the first half of the 20th century with development of radar. Radiophysical experiments on excitation of surface electromagnetic waves on conductors in the centimeter range of radio waves are presented. A method for selective excitation of SEWs is described. Its essence is that the space radio wave radiation is suppressed by screening while the SEW on the conductive strip is excited by isolated currents launched through a slit in the screen.

Теория ленточной антенны, расположенной на плоской границе раздела одноосного магнитного метаматериала и изотропной среды

A study is made of the electrodynamic characteristics of an antenna having the form of an infinitesimally thin, perfectly conducting narrow strip located at the plane interface of a uniaxial magnetic metamaterial and an isotropic magnetodielectric medium. The antenna is perpendicular to the anisotropy axis of the metamaterial and is excited by a time-harmonic given voltage. Singular integral equations for the antenna current are obtained in the case of an infinitely long strip conductor. Based on the solution of these equations, the current distribution and input impedance of the antenna are found and analyzed. The limits of applicability of an approximate method based on the transmission line theory for determining the antenna characteristics are established. Within the framework of this method, the results obtained are generalized to the case of a finite-length strip antenna.

Single-Beam Leaky-Wave Antenna With Lateral Continuous Scanning Functionality Based on Spoof Surface Plasmon Transmission Line

A continuous beam scanning leaky-wave antenna (LWA) supporting lateral radiation is proposed in this paper. It is based on a spoof surface plasmon (SSP) transmission line (TL) which is a single-layer conductor structure. The proposed SSP TL is slotted periodically with rectangular holes on the metallic strip conductor. Circular patches are loaded periodically along one side of the SSP TL to achieve an additional momentum for converting the slow-wave mode to a fast-wave mode and then modulate the SSP wave into a spatial wave. The proposed SSP LWA produces a single lateral beam rather than double beams usually existed in conventional SSP LWAs, as highly desired in many applications. As operating frequencies increase from 7 to 15 GHz, the proposed SSP LWA achieves a continuous beam scanning range of 65° from forward to backward with stable high gains. As its primary advantage, this proposed SSP LWA does not lose radiation efficiency even at broadside, which is often suffered by conventional LWAs. Both the transmission characteristics of the SSP TL and the radiation mechanism of the SSP LWA are investigated. Finally, the proposed SSP LWA is designed, fabricated, and measured. The measured results agree well with the simulated ones over a wide operating frequency range, which validates its good performances. The proposed SSP LWAs provide a low-cost solution to planarly integrated communication systems.

Crack branching in polymers

One of the little-studied problems of modern mechanics and the physics of fracture is the crack branching in materials of a different nature. For its research, an analysis of the criteria and mechanisms for crack branching. The investigations of crack branching in polymers and metals, fractographic investigation of the fracture surface, criteria for crack branching as a dynamic stress intensity factor, crack speed are considered. Experimental studies of crack branching in a brittle polymer, measuring of crack velocity by breaking the conductive strips with rectilinear propagation and branching of the crack have been carried out. A measurement installation was created on the basis of a precision signal converter of resistance thermometers and thermocouples “Tercon” connected to a computer. It is established that the crack at branching in brittle polymers reaches the limiting propagation speed 500–800 m/s. A hypothesis is proposed for the physical mechanism of crack branching.

Propagation Loss Reduction Between On-Body Antennas by Using a Conductive Strip Line

This letter proposes a very simple solution to reduce the propagation loss between two antennas/sensors on body at 2.45 GHz by utilizing a flexible conductive strip line (CSL). The performance of the CSL is comparable to that of the free-access transmission line in the work by Tran et al. in some certain cases. The transmission improvement by the CSL is verified by measurement results on a perfect electrical conductor plane, on a phantom, and on a real body more than 20 dB for non-line-of-sight scenarios. Dimension parameters of the CSL are optimized so that the highest improvement by the CSL can be achieved and it is easy to be integrated into clothes. Moreover, the specific absorption rate is satisfied when the CSL is deployed near body.

Optimization of a thermoelectric generator for heavy-duty vehicles

A thermoelectric generator used to recover energy from the exhaust gases of a heavy-duty freight vehicle is numerically simulated and optimized using two different algorithms: a gradient-based search method, and a global and local direct search method. The model uses a one-dimensional finite volume method to calculate the temperature and the convective heat transfer of the hot and cold fluids along the streamwise direction, as well as the pressure drop, and employs a thermal resistance network and a global energy balance to account for the heat transfer and the thermoelectric effect. Three different heat exchanger configurations are studied with plain, offset strip or triangular fins. The objective function is the net output power, and the geometrical dimensions of the heat exchanger and thermoelectric units are taken as design variables. The results show that the height of the fins, the spacing between them, the height and side length of the cross section of the thermoelectric units, and the distance between the legs are critical parameters in the optimization process. The thickness of the fins, wall ducts, electrical conductor and ceramic strips should be as small as possible, as well as the height of the cooling wall duct. The two optimization methods yield similar optimal solutions.

The space and time behaviour of the constructal plate generating heat

In this paper, a study of the elemental construct of an I-shaped fin cooling a heat generating plate is conducted in the framework of the constructal design method. Using the minimization of the maximum excess of temperature as an objective and considering that heat is generated in the conductive strip within a certain surface and with a different amplitude from the plate, the constructal design method permits to obtain a new optimal shape ratio (more general than the optimums found in the literature considering no-generation in the conductive strip or heat generated with the same amplitude in the two materials). Then, the thermal model used until here in stationary state (hypotheses on heat diffusion) is extended to take into account the time. The analytical solution obtained (verified numerically) is compared to classical heat diffusion through an engineering application (cooling an electronic device) where it keeps a good precision for times larger than 1% of the stationary time.

An anti-passivation ink for the preparation of electrodes for use in electrochemical immunoassays.

p-Nitrophenylphosphate (PNPP) is usually employed as the substrate for enzyme-linked immunosorbent assays. p-Nitrophenol (PNP), the product of PNPP, with the catalyst alkaline phosphatase (ALP), will passivate an electrode, which limits applications in electrochemical analysis. A novel anti-passivation ink used in the preparation of a graphene/ionic liquid/chitosan composited (rGO/IL/Chi) electrode is proposed to solve the problem. The anti-passivation electrode was fabricated by directly writing the graphene-ionic liquid-chitosan composite on a single-side conductive gold strip. A glassy carbon electrode, a screen-printed electrode, and a graphene-chitosan composite-modified screen-printed electrode were investigated for comparison. Scanning electron microscopy was used to characterize the surface structure of the four different electrodes and cyclic voltammetry was carried out to compare their performance. The results showed that the rGO/IL/Chi electrode had the best performance according to its low peak potential and large peak current. Amperometric responses of the different electrodes to PNP proved that only the rGO/IL/Chi electrode was capable of anti-passivation. The detection of cardiac troponin I was used as a test example for electrochemical immunoassay. Differential pulse voltammetry was performed to detect cardiac troponin I and obtain a calibration curve. The limit of detection was 0.05 ng/ml.

Frequency reconfigurable antenna for cognitive radios with sequential UWB mode of perception and multiband mode of operation

AbstractIn this work, an UWB/narrow band reconfigurable elliptical-shaped monopole antenna for cognitive radio applications with sequential perception and operation modes is presented. The proposed approach consists in integrating a reconfigurable filter, in an UWB antenna ground plan, by the mean of four horizontal slots and integrated switches that allow inserting/removing/varying zeros and poles in the frequency response. By acting on the slot lengths in order to alter their resonance frequencies, the different switch configurations allow the antenna to switch between an UWB mode that could be used for the perception (sensing) and different narrowband modes, mono-band and dual-band, that could be used for the operation at 2.4 or/and 3.5 GHz. To validate the concept, an experimental prototype has been fabricated and a good agreement between the simulated and the measured S-parameters has been obtained. While the presented work uses the presence/absence of a perfect conductive strip (PEC) to model real switch operation, it is believed that the obtained results conjugated with previous work using real switches on a very similar structure allows validating approach.

Radiofrequency planar surface coil for magnetic resonance: When the use of a circular wire gives a noticeable advantage with respect to a flat strip conductor?

Depending on their cross-sectional shape, commonly used conductors for radiofrequency (RF) Magnetic Resonance (MR) coils can be categorized into circular wires and flat strips. Due to a more symmetrical current distribution inside conductor volume, coils constituted by wire conductors provide better overall performance in unloaded conditions with respect to the ones made of strip conductor, although wire conductors are difficult to handle for coil manufacturing and additional mechanical competencies are required. Nevertheless, the accomplishment of the best coil performance during imaging, i.e. in the presence of a sample, remains the main issue in MRI. It follows that the use of wire conductors instead of strip ones is worthwhile only if the correspondent increase in coil quality factor with sample is substantial: this is related to the ratio between sample and coil resistance.This paper proposes the application of a finite element method (FEM)-based numerical approach for separately estimating the conductor and radiative losses in planar surface loops characterized by different cross-sectional shapes (circular wire and flat strip) in conjunction with a vector potential calculation-based method for sample-induced resistance estimation. Simulation data were acquired from 5.7 to 128 MHz, for four different size loops (from 2 to 15 cm diameters), with the scope of evaluating the region in the frequency-loop diameter plane where the use of a circular wire conductor gives a noticeable advantage with respect to the flat strip in maximizing signal-to-noise ratio (SNR) in MR applications.

2D/3D switchable displays through PDLC reverse mode parallax barrier

ABSTRACTIn this paper, we present a new type of parallax barrier, for switchable 2D/3D display vision, obtained by using a Reverse Mode Polymer Dispersed Liquid Crystal display (RV-PDLC). The parallax barrier was prepared by sandwiching the RV-PDLC film between two ITO conductive glass supports. Strips of ITO were removed from one of the supports, in order to alternate conductive to not conductive strips. In this way the RV-PDLC films could be electrically switched in a parallax barrier able to turn a 2D image in a 3D one. The RV-PDLC barrier was obtained in tree steps: (1) a nematic diacrylate monomer (NDM) was dissolved in a nematic liquid crystal (NLC) in the presence of a small quantity of radical polymerisation initiator; (2) the mixture was homeotropically aligned between the glass conductive supports, previously treated with an aligning chemical; (3) the liquid crystal monomer was polymerised by UV curing. A 2D/3D switchable device was finally obtained by coupling the parallax barrier with a 2D tablet display.

Алгебраические модели полосковых линий в многослойной диэлектрической среде

The electrodynamic problem is reduced to an integral equation with respect to the current density on the strip conductor. It is solved by the projection method using the Chebyshev basis. A homogeneous system of linear algebraic equations (SLAE) is described with respect to the coefficients of the expansion of the longitudinal and transverse components of the current density in terms of Chebyshev polynomials with weight functions that take into account the specificity of the field at the edges of the strip conductors. On the basis of the condition that the determinant of this system is zero the constants of the natural waves propagation are determined by numerical methods. A procedure for improving the convergence of slowly convergent series for the matrix coefficients of SLAE is carried out. The problem of high-accuracy calculation of the functions represented in the form of infinite slowly convergent series, by means of which the matrix coefficients are determined, is solved. A universal formula independent of the number of layers for calculating the wave impedances of natural waves is obtained. The use of the Chebyshev basis and the improvement of the series convergence made it possible to develop an effective algorithm for calculating the basic electrodynamic parameters of the strip lines - the propagation constants and the wave impedances of the natural waves. The constructed algebraic models of strip lines allow computer simulation to obtain numerical results quickly and with high accuracy irrespectively of the number of dielectric layers and their parameters. On the basis of the developed algorithm we created a set of computer programs for calculating the propagation constants, the coefficients of the current density decomposition in terms of Chebyshev weighted polynomials and the wave impedances of screened strip lines of various types: a single and connected microstrip lines (with side and face communication); coplanar strip line; slit line and coplanar waveguide. These programs allow determining the electrodynamic parameters of the main wave and up to 50 waves of higher types. The results of a numerical analysis of the convergence of the developed algorithm for the calculation of natural waves are presented. This confirms the effectiveness of the constructed models. Numerical results obtained without the procedure for improving the convergence of series for matrix coefficients and results obtained by the projection method using the trigonometric basis are given.

Current Distribution in a Gyrotropic Microstrip Structure when Excited by a Plane Electromagnetic Wave

The problem of the distribution of the surface current density in a gyrotropic microstrip structure representing an infinitely thin ideally conducting strip arranged on a substrate of a chiral metamaterial metallized from one side and excited by a plane wave is reduced to a one-dimensional singular integral equation with a Cauchy singularity. The complex current distributions along the strip conductor are presented for different types of substrate and the wave-incidence angles.

Coupling of Impulsive EM Plane-Wave Fields to Narrow Conductive Strips: An Analysis Based on the Concept of External Impedance

The pulsed electromagnetic coupling to a narrow perfectly electrically conducting strip is analyzed using the concept of external impedance. For postulated spatial electric-current distributions, the problem is reduced to an integral equation of the time-convolution type that is, under the narrow-strip assumption, solved numerically via a marching-on-in-time scheme. Illustrative numerical examples concerning the impulsive plane-wave incidence demonstrate the space-time behavior of the induced electric-current density.

A study on the effect of tool electrode thickness on MRR, and TWR in electrical discharge turning process

Turning by electrical discharge machining (EDM) is an emerging area of research. Generally, wire-EDM is used in EDM turning because it is not concerned with electrode tooling cost. In EDM turning wire electrode leaves cusps on the machined surface because of its small diameters and wire breakage which greatly affect the surface finish of the machined part. Moreover, one of the limitations of the process is low machining speed as compared to constituent processes. In this study, conventional EDM was employed for turning purpose in order to generate free-form cylindrical geometries on difficult-to-cut materials. Therefore, a specially designed turning spindle was mounted on a conventional die-sinking EDM machine to rotate the work piece. A conductive preshaped strip of copper as a forming tool is fed (reciprocate) continuously against the rotating work piece; thus, a mirror image of the tool is formed on the circumference of the work piece. In this way, an axisymmetric work piece can be made with small tools. The developed process is termed as the electrical discharge turning (EDT). In the experiments, the effect of machining parameters, such as pulse-on time, peak current, gap voltage and tool thickness on the MRR, and TWR were investigated and practical machining was carried out by turning of SS-304 stainless steel work piece.

Multilayer bandpass filter‐polarizer with stopband extension far beyond twofold center frequency

AbstractWe propose a multilayer bandpass filter in which every resonator consists of two identical dielectric layers separated by a grating of parallel strip conductors. The resonators themselves are separated from each other and from the ambient space by gratings of strip conductors with an axis orthogonal to the axis of the gratings inside the resonators. The proposed filter construction acts at the same time as a polarizer. The device frequency response computed with use of the provided simple formulas is in a good qualitative agreement with numerical electromagnetic analysis of its 3D model.

Equivalent Surface Impedance of an Infinite Periodic Array of Slot Impedance Loads with Dielectric Coating

The problem of plane-wave excitation of an infinite array of slot impedance loads with a dielectric layer is considered in order to determine the equivalent surface impedance. The solution of the problem is found by the method of integral equations, solved numerically by the Krylov–Bogolyubov method, which reduces the integral equation to a system of linear algebraic equations. The numerical results are presented in the form of dependences of the equivalent surface impedance on the geometric dimensions of the structure at fixed values of the period of the array, the angle of incidence, and the thickness of the dielectric layer. It is shown that the equivalent surface impedance can be controlled by varying the width of the slot and the strip conductor. The dependences obtained are compared with the characteristics of an array of slot impedance loads without a dielectric layer.

Collision Monitoring of Foreign Object on CFRP Laminate Utilizing Electrostatic Induction

In this paper, a collision monitoring method utilizing electrostatic induction is proposed, designed, tested, and validated. When a foreign object, which is regarded as a charged body because any object is charged to a greater or lesser extent, approaches and collides with a grounded electric conductive material, an electric current caused by electrostatic induction flows to ground. The electric current is used for collision monitoring in this paper. The principle of the proposed collision monitoring method can be used for any conductive plate, which is in the air or a vacuum. However, the method is particularly aimed at collision monitoring on carbon fiber reinforced polymer (CFRP) structures for reducing the inspection cost by identifying the area where detailed inspection, such as ultrasonic inspection, needs to be conducted. The sensors are composed of the monitored object of a large conductive plate, such as a CFRP laminate, and strip conductors, such as copper tape arrayed in grid. When a foreign object collides with the monitored object, electric currents flowing through the strip conductors are measured and analyzed, and the collision point, angle, and speed of the foreign object are identified using an optimization method. As a result of several experiments, the collision point, angle, and speed are identified with high accuracy (within 5% error except for a specific case).