Capacitor Modelling in COMSOL Multiphysics® & FEMM

A quick introduction about me and the course

:)

A capacitor is a device that stores electrical energy in an electric field. It is a passive electronic component with two terminals.

Capacitors contain two conducting materials like metal inside the capacitor, and those two metals are separated from each other with an electric insulator or a vacuum. Capacitors are used as frequency-dependent impedance and it is used for temporary energy storage.

The capacitors are categorized into two groups they are polarized and non-polarized capacitors. The polystyrene capacitor, ceramic capacitor, Teflon capacitors are non-polarized capacitors. Air or Vaccum, rubber, oil, paper, mica, glass, ceramic, etc are the dielectric materials.

Few shortcuts (windows PC) while using the software:
MOVING BETWEEN WINDOWS AND SECTIONS ON THE COMSOL DESKTOP

Keyboard shortcuts are quick ways to navigate between the windows on the COMSOL Desktop and to switch focus between windows and Settings window sections:

•Press Ctrl+Tab to switch focus to the next window on the desktop.

•Press Ctrl+Shift+Tab to switch focus to the previous window in the desktop.

•Press Ctrl+Alt+left arrow to switch focus to the Model Builder window.

•Press Ctrl+Alt+right arrow to switch focus to the Settings window.

•Press Ctrl+Alt+up arrow to switch focus to the previous section in the Settings window.

•Press Ctrl+Alt+down arrow to switch focus to the next section in the Settings window.

Parameters nodes are available under Global Definitions for creating and defining global parameters. One Parameter node is always available, and it cannot be moved or deleted. Additional Parameter nodes can be added as desired, if you would like to group parameters in several Parameter nodes, perhaps with descriptive labels. This is also useful if you want to use some parameters for preprocessing only and then not include them in parametric sweeps. You can move and delete Parameter nodes that you have added. If you group nodes by type, the Parameters nodes appear under Global Definitions>Parameters.

Parameters are useful in the following context:

•As parameters in dimensions for geometric primitives or other geometry operations

•As parameters for the mesh generators to, for example, specify the mesh size

•As parameters to control some aspects of the solution process

•To quickly evaluate a mathematical expression, including unit conversion

•In physics interface and feature settings, expressions, and coupling operators

•In expressions when evaluating results

The Electromagnetics Interfaces

For simulating electromagnetic fields, COMSOL Multiphysics has three physics interfaces.

•Electrostatics

•Electric Currents

•Magnetic Fields

In COMSOL Multiphysics models, you can add one or more materials, which are named collections of material properties. Each such material is represented by a Material node. Each material includes a number of physical properties with the values or functions (for temperature-dependent material properties, for example) that describe the material.

The Mesh nodes enable the discretization of the modelling domain into small units of simple shapes, referred to as mesh elements. See The Mesh Node for more information.

A mesh is a result of building a meshing sequence. A meshing sequence consists of Meshing Operations and Attributes. The attribute nodes store properties that are used by the operations when creating the mesh.

Building an operation creates or modifies the mesh on the entities defined by the operation’s selection. Some of the operations use properties defined by attributes; for example, Free Tetrahedral reads properties from the Size, Distribution, Size Expression and Corner Refinement attribute nodes.

The Frequency Domain study and study step are used to compute the response of a linear or linearized model subjected to harmonic excitation for one or several frequencies.

For example, in solid mechanics, it is used to compute the frequency response of a mechanical structure with respect to particular load distributions and frequencies. In acoustics and electromagnetics, it is used to compute the transmission and reflection versus frequency. A Frequency Domain study step accounts for the effects of all eigenmodes that are properly resolved by the mesh and how they couple with the applied loads or excitations. The output of a Frequency Domain study step is typically displayed as a transfer function, for example, magnitude or phase of deformation, sound pressure, impedance, or scattering parameters versus frequency.