scholarly journals Simulation of space charge transport in solid dielectric materials using transmission lines modeling method

2019 ◽  
Vol 09 (06) ◽  
pp. 1950051
Author(s):  
Amin Shamsi ◽  
Alireza Ganjovi ◽  
Amirabbas Shayegani Akmal
Keyword(s):  
Transmission Line ◽  
Charge Density ◽  
Space Charge ◽  
Current Density ◽  
Dielectric Material ◽  
Dielectric Materials ◽  
Solid Dielectric ◽  
Recombination Rates ◽  
Net Charge ◽  
Charged Species

In this paper, a lumped RC circuit model, which is based on the Transmission Line Modeling (TLM) method, is used to describe the space charge production and displacement mechanisms in three different solid dielectric materials (LDPE, PTFE and FR4). Each dielectric material is considered as a transmission line with the capacitive and resistance elements. The obtained circuit equations are solved along with the continuity equations for the various charged species in the bulk of solid dielectric material. The electric potential and field, density of different charged species and their recombination rates, resistive and capacitive properties of the solid dielectric material are calculated. In addition, the effects of the variations in the applied voltage, dielectric permittivity and temperature on these physical parameters are examined. Besides, compared with LDPE and PTFE, the net charge density increment rate in FR4 is much higher. Moreover, the influences of temperature on the net charge density in LDPE are not significant. Furthermore, at the higher applied voltages, the current density is increased. Interestingly, the effects of temperature variations on the recombination rates, net charge and current density in LDPE are much lower. Hence, the suitability of LDPE as solid dielectric material is proved.

scholarly journals Frequency response analysis of dielectric materials in a parallel-plate transmission line

2021 ◽  
Vol 22 (2) ◽  
pp. 893
Author(s):  
Aaron Don Munsayac Africa ◽  
Gregory James Pe ◽  
Robert Ianny Roy Quijano
Keyword(s):  
Transmission Line ◽  
Frequency Response ◽  
Transmission Lines ◽  
Parallel Plate ◽  
Dielectric Material ◽  
Signal Transmission ◽  
Sheet Material ◽  
Dielectric Materials ◽  
Response Analysis ◽  
Parallel Plates

A transmission line allows different frequencies to conduct alternating current (AC). They are a peculiar type of wire that allows signal transmission while making it resistant to external noises. A parallel-plate transmission line is a type of transmission line designed with two parallel plates with a dielectric sheet material in the center, as the name implies. The parallel-plate transmission lines are usually used for a miniature setup in which the line prevents the signal from losing power. However, the line's frequency response is a varying setup in which a change in a parameter can fully change the frequency response of the line, and in turn trigger inefficiency. With this, different factors such as the conductor, the size, and the dielectric material of the parallel-plate transmission line can affect its frequency response. Specifically, the analysis of the transmission would test the various frequency responses when the dielectric sheet content is varied. The researchers will carry out experiments on air, Teflon, plexiglass, and E type glass dielectrics.

scholarly journals 1D Mathematical Modelling of Non-Stationary Ion Transfer in the Diffusion Layer Adjacent to an Ion-Exchange Membrane in Galvanostatic Mode

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 84 ◽  
Author(s):  
Aminat Uzdenova ◽  
Anna Kovalenko ◽  
Makhamet Urtenov ◽  
Victor Nikonenko
Keyword(s):  
Ion Exchange ◽  
Charge Density ◽  
Space Charge ◽  
Diffusion Layer ◽  
Current Density ◽  
Space Charge Density ◽  
Ion Exchange Membrane ◽  
Quasi Equilibrium ◽  
Ion Transfer ◽  
Exchange Membrane

The use of the Nernst–Planck and Poisson (NPP) equations allows computation of the space charge density near solution/electrode or solution/ion-exchange membrane interface. This is important in modelling ion transfer, especially when taking into account electroconvective transport. The most solutions in literature use the condition setting a potential difference in the system (potentiostatic or potentiodynamic mode). However, very often in practice and experiment (such as chronopotentiometry and voltammetry), the galvanostatic/galvanodynamic mode is applied. In this study, a depleted stagnant diffusion layer adjacent to an ion-exchange membrane is considered. In this article, a new boundary condition is proposed, which sets a total current density, i, via an equation expressing the potential gradient as an explicit function of i. The numerical solution of the problem is compared with an approximate solution, which is obtained by a combination of numerical solution in one part of the diffusion layer (including the electroneutral region and the extended space charge region, zone (I) with an analytical solution in the other part (the quasi-equilibrium electric double layer (EDL), zone (II). It is shown that this approach (called the “zonal” model) allows reducing the computational complexity of the problem tens of times without significant loss of accuracy. An additional simplification is introduced by neglecting the thickness of the quasi-equilibrium EDL in comparison to the diffusion layer thickness (the “simplified” model). For the first time, the distributions of concentrations, space charge density and current density along the distance to an ion-exchange membrane surface are computed as functions of time in galvanostatic mode. The calculation of the transition time, τ, for an ion-exchange membrane agree with an experiment from literature. It is suggested that rapid changes of space charge density, and current density with time and distance, could lead to lateral electroosmotic flows delaying depletion of near-surface solution and increasing τ.

Numerical Solution for the Forward Steady-State Behaviour of an Abrupt p+-n Junction

1968 ◽  
Vol 23 (8) ◽  
pp. 1135-1146
Author(s):  
M. Sánchez
Keyword(s):  
Steady State ◽  
Charge Density ◽  
Space Charge ◽  
Current Density ◽  
Space Charge Density ◽  
Space Charge Layer ◽  
Charge Layer ◽  
Density Distributions ◽  
State Behaviour ◽  
Steady State Behaviour

The forward steady-state behaviour of a one-dimensional abrupt p+-n junction germanium diode at zero and at low to high injection levels is analysed. For this purpose the numerical integration of the current differential equations, the continuity equations, and Poisson’s differential equation is performed not only inside the space-charge layer but also along the quasineutral regions of the diode satisfying the boundary and continuity conditions. The integration is made on a digital computer without applying the Boltzmann equilibrium approximation in the space-charge layer and the space-charge neutrality approximation in the quasineutral regions. Furthermore, the acoustical and optical mode scattering, the ionized impurity scattering, and the Hall-Shockley-Read and Auger recombination processes are included in the calculation. The method of solution applied differs from those already available in the literature and permits the “exact” computation of the space-charge density inside the relatively long (compared with the Debye length) quasineutral p and n regions of the diode considered. The numerical results for the hole and electron concentration distributions, the electric field distributions, the electron current density distributions, the electrostatic potential distributions and the space-charge density distributions are reported for five values of the total current density across the p-n junction. The comparison of the obtained numerical solutions with the closed analytical solutions for zero bias (as a test of the computer program) on the one side and of the computed current/voltage characteristic of the p-n junction with experimental values on the other side shows satisfactory agreement.

Mathematical model to predict the characteristics of polarization in dielectric materials: The concept of piezoelectrcity and electrostriction

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Dielectric Material ◽  
Strain Curve ◽  
Dielectric Materials ◽  
Lead Zirconate ◽  
Simulation Software ◽  
Constitutive Law ◽  
Basic Material

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.

Measurements of the Net Charge Density of Space Plasmas

2021 ◽  
Author(s):  
Chao Shen ◽  
Yufei Zhou ◽  
Lai Gao
Keyword(s):  
Charge Density ◽  
Space Plasmas ◽  
Net Charge

Surface defect chemistry of Y-substituted and hydrated BaZrO3 with subsurface space-charge regions

2016 ◽  
Vol 4 (19) ◽  
pp. 7437-7444 ◽  
Author(s):  
Jonathan M. Polfus ◽  
Tor S. Bjørheim ◽  
Truls Norby ◽  
Rune Bredesen
Keyword(s):  
Surface Layer ◽  
Space Charge ◽  
Space Charge Region ◽  
First Principles ◽  
Surface Defect ◽  
Surface Defects ◽  
Defect Chemistry ◽  
First Principles Calculations ◽  
Proton Conducting ◽  
Charged Species

First-principles calculations were utilized to elucidate the complete defect equilibria of surfaces of proton conducting BaZrO3, encompassing charged species adsorbed to the surface, defects in the surface layer as well as in the subsurface space-charge region and bulk.

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