838 Words4 Pages

Finite Difference Time Domain

Electromagnetic field theory is a theory that explains the relationship between an electric field and a magnetic field, causing the electromagnetic wave propagation[44]. This theory was proposed by James Clark Maxwell in 1865. According to Maxwell, the electric field that changes will give rise to a magnetic field. Meanwhile, Faraday argued that the change in the magnetic field induce an electric field. Thus, the relationship between an electric field and a magnetic field causes an electromagnetic wave. It can be said that the electromagnetic wave is the wave blend between electric fields with magnetic fields caused by electrical charges move accelerated.

The finite-difference time-domain (FDTD) is a computational*…show more content…*

For instance in vacuum, the phase velocity of the numerical wave modes in the FDTD mesh can be different from vacuum speed of light. In fact the phase velocity of the numerical wave modes is a function of wavelength, the size of the cells and the direction of propagation. This numerical dispersion can carry to non-physical output such as dilatation of single-pulse waveforms, imprecise canceling of multiple scattered wave and pseudo refraction [49]. It is described that to limit the amount of numerical dispersion, the size of each cell must be at least ten times smaller than the shortest wavelength that propagate on a space grid. Of course the numerical dispersion will be reduced even further if smaller cell size is used. However using a smaller cell size will increase the number of cells needed to fill the space grid and causes increase computational demand and time of the model. Where λo is the operating wavelength, the rule*…show more content…*

Sources are characterized according to their shape or FDTD implementation. A source can formed of sinusoidal or Gaussian pulse. A Gaussian pulse is desirable as the excitation because its frequency spectrum is also Gaussian and will provide frequency-domain information from dc to the highest frequency that will propagate in the numerical lattice[42]. Usually, a Gaussian Pulse is used to represent the PD source. Gaussian pulse could be form in certain frequency that shown in Figure II 17. Figure II 17 Gaussian pulse as source in several frequency

Absorbing boundary condition

Absorbing boundary conditions are needed to keep E and H fields not being reflected back into the space grid. This matter can be solved by applying Perfect Matched Layer (PML). PML is a technique of free-space simulation for solving unbounded electromagnetic problems with FDTD method. As regards PML, it introduces additional unphysical quantities and encompasses a few FDTD layers, shrinking the effective volume of a scenario. However, the advantage of PML is that it is not so much angle-dependent and can be placed close to radiating sources without the risk of instability[51]. The PML concept is shown in Figure II 18. Figure II 18 The PML Concept that shown no reflection on the outer layer

In this thesis, the FDTD calculation would be done by using electromagnetic simulation software which

Electromagnetic field theory is a theory that explains the relationship between an electric field and a magnetic field, causing the electromagnetic wave propagation[44]. This theory was proposed by James Clark Maxwell in 1865. According to Maxwell, the electric field that changes will give rise to a magnetic field. Meanwhile, Faraday argued that the change in the magnetic field induce an electric field. Thus, the relationship between an electric field and a magnetic field causes an electromagnetic wave. It can be said that the electromagnetic wave is the wave blend between electric fields with magnetic fields caused by electrical charges move accelerated.

The finite-difference time-domain (FDTD) is a computational

For instance in vacuum, the phase velocity of the numerical wave modes in the FDTD mesh can be different from vacuum speed of light. In fact the phase velocity of the numerical wave modes is a function of wavelength, the size of the cells and the direction of propagation. This numerical dispersion can carry to non-physical output such as dilatation of single-pulse waveforms, imprecise canceling of multiple scattered wave and pseudo refraction [49]. It is described that to limit the amount of numerical dispersion, the size of each cell must be at least ten times smaller than the shortest wavelength that propagate on a space grid. Of course the numerical dispersion will be reduced even further if smaller cell size is used. However using a smaller cell size will increase the number of cells needed to fill the space grid and causes increase computational demand and time of the model. Where λo is the operating wavelength, the rule

Sources are characterized according to their shape or FDTD implementation. A source can formed of sinusoidal or Gaussian pulse. A Gaussian pulse is desirable as the excitation because its frequency spectrum is also Gaussian and will provide frequency-domain information from dc to the highest frequency that will propagate in the numerical lattice[42]. Usually, a Gaussian Pulse is used to represent the PD source. Gaussian pulse could be form in certain frequency that shown in Figure II 17. Figure II 17 Gaussian pulse as source in several frequency

Absorbing boundary condition

Absorbing boundary conditions are needed to keep E and H fields not being reflected back into the space grid. This matter can be solved by applying Perfect Matched Layer (PML). PML is a technique of free-space simulation for solving unbounded electromagnetic problems with FDTD method. As regards PML, it introduces additional unphysical quantities and encompasses a few FDTD layers, shrinking the effective volume of a scenario. However, the advantage of PML is that it is not so much angle-dependent and can be placed close to radiating sources without the risk of instability[51]. The PML concept is shown in Figure II 18. Figure II 18 The PML Concept that shown no reflection on the outer layer

In this thesis, the FDTD calculation would be done by using electromagnetic simulation software which

Related

## UBT1 Task 1: Electricity

712 Words | 3 Pages1831- Using his invention the induction ring, Michael Faraday proved that electricity can be induced (made) by changes in an electromagnetic field. Faraday’s experiments about how electric current works, led to the understanding of electrical transformers and motors. This experiment became Faraday’s Law, which became one of the Maxwell Equations (Administrator, 2007). 1890 - Heinrich Hertz (1857-1894) a German physicist, laid the ground work for the vacuum tube. He laid the foundation for the future development of radio, telephone, telegraph, and even television.

## Luigi Galvani Thesis Statement

1290 Words | 6 PagesGalvanometer gives the deflection which is proportional to the electric current flowing through it. It works as an actuator by producing a rotary deflection. Also, known as a (pointer) in response to electric current flowing through a coil in a constant magnetic

## Ohm's Law Lab Report

1206 Words | 5 PagesThe proportionality constant, R, is known as the resistance and is determined by both material properties (the intrinsic resistivity) and geometry (length and cross-sectional area of the active material). In equation form, Ohm’s law is: V = IR. It is important to understand just what is meant by these quantities. The current (I) is a measure of how many electrons are flowing past a given point during a set amount of time. The current flows because of the electric potential (V), sometimes referred to as the voltage, applied to a circuit.

## Vehicle Suspension System Research Paper

1922 Words | 8 PagesMR fluids require small voltages and current, while ER fluids require very large voltage and very small currents. According to the experts, MR fluids have become a widely studied “smart” fluid due to its less consumption of energy. The fluid that is transferring from top to bottom or from bottom to top must pass through the MR valve. The MR valve is fixed size orifice with ability to apply a magnetic field to the orifice volume. This magnetic field changes the viscosity of MR fluid, which will cause change in flow rate.

## Electric Field Lab

467 Words | 2 PagesIt appears that the diagrams do agree with my understanding of the concept of equipotential and electric fields. For both of the maps, the electric field lines are closer in the middle, which means that the electric fields are stronger in the middle. Most of the voltages have similar electric potentials, which explains that no work is done. Since no work done is being done on these field lines and the equipotential lines should be perpendicular to the electric field lines. However, it appears to be slightly off from what should be expected, and this may be caused by some sources of

## Electric Field Lines Lab Report

816 Words | 4 PagesThe purpose of this experiment was to use charged electrodes on conducting paper and voltmeter to discover electric field. The experiment also discovered the relationship between equipotential lines and electric field lines. The purpose of the experiment was to find if the theory that equipotential lines always run perpendicular to electric field lines hold true. The equation used in this experiment is E = ∆V/∆d. The experimental value yielded a result of y = -100x + 10 and the theoretical yielded a -100 V/m.

## Essay On Electromagnetism

1345 Words | 6 PagesAnother definition for electromagnets are solenoids wound around a central iron core. The magnetic field generated by the coil of wire magnetizes the core, increasing the total field. The difference in simple terms: a solenoid is a long, thin helical loop of wire. An electromagnet is a magnet whose magnetic properties depend on an electric current. A solenoid is just a coil of wire, but when you run a current through it, you create an electromagnet.

## Nuclear Magnetic Resonance Imaging Lab Report

1131 Words | 5 PagesTopic: Magnetic resonance imaging Introduction: Nuclear magnetic resonance which is nuclei absorb and re-emit electromagnetic radiation phenomenon under a magnetic field. Actually, all elements’ nuclei are electrically charged and spin with different energy level to behave like a magnet. When it is at lower energy which will generate a magnetic field in the direction of the external magnetic field and opposite direction with spin at higher energy. The energy difference between them will correspond to radio frequency called the nuclear magnetic moment. This energy gap refers specific frequency which depends on properties of the isotope of the atoms and the strength of the magnetic field.

## Electromagnet Lab Report

1276 Words | 6 PagesTesting the Strength of the Electromagnet by Changing the Number of Coils Aim The aim of this experiment is to investigate how the strength of an electromagnet is affected by the number of coil turns around the iron c-core. Hypothesis As the number of wire coils increases, the strength of the magnetic field (the electromagnet’s strength) will also increase. This means that the number of paper clips that attach to the electromagnet will increase. Explanation of Hypothesis/background: When a DC (Direct Current) electric current flows through a wire, a magnetic field is created. Wrapping the wire in a coil concentrates and increases the magnetic field, because the additive effect of each turn of the wire.

## Helmholtz Coils Lab Report

1048 Words | 5 PagesIntroduction When a charged particle is moving through a magnetic field, it experiences a magnetic Lorentz force given by F ⃗=qv ⃗ ×B ⃗ (1) where q is the charge of the particle, v is the velocity of the charge q and B is the magnetic field. In this experiment, an electron source, which is the heated filament, an electrode and Helmholtz coils are used to generate the magnetic field. Both the electrode and heated filament are placed in a near vacuum container containing a small amount of mercury.

### UBT1 Task 1: Electricity

712 Words | 3 Pages### Luigi Galvani Thesis Statement

1290 Words | 6 Pages### Ohm's Law Lab Report

1206 Words | 5 Pages### Vehicle Suspension System Research Paper

1922 Words | 8 Pages### Electric Field Lab

467 Words | 2 Pages### Electric Field Lines Lab Report

816 Words | 4 Pages### Essay On Electromagnetism

1345 Words | 6 Pages### Nuclear Magnetic Resonance Imaging Lab Report

1131 Words | 5 Pages### Electromagnet Lab Report

1276 Words | 6 Pages### Helmholtz Coils Lab Report

1048 Words | 5 Pages