COMS7309 Computational Techniques in Electromagnetics - Assignment 2: Double-slit experiment
The University of Queensland
School of Information Technology & Electrical Engineering
COMS7309 Computational Techniques in Electromagnetics Assignment 2, S2 2023
BACKGROUNDS
The double-slit experiment is a milestone in physics, which was first performed by Thomas Young in 1801. The experiment performed by Young demonstrated that visible light possesses wave behaviour. The following research and experiments on this topic reveal that both light and matter can satisfy the classical definitions of waves and particles, which are seemingly incongruous. The conclusions from the double-slit experiments form the evidence for the basic probabilistic nature of quantum mechanics.
This assignment uses the two-dimensional (2D) finite-difference-time-domain (FDTD) technique to emulate the double-slit experiment with electromagnetic waves. From the FDTD simulation, we will observe the diffraction and interference phenomena of the electromagnetic wave, similar to those observed in the double-slit experiment with visible light.
MATERIALS
In this assignment, a framework of 2D FDTD code is provided. Based on this framework, a complete 2D FDTD code is required to be programmed.
The simulation configuration is shown in Figure 1.
Figure 1. The simulation configuration of 2D-FDTD. The blue circle indicates the location of the line source. The grey region is the PML and the black region is the dielectric plate.
In this assignment, a computation domain with the size of 500 𝑚𝑚 × 500 𝑚𝑚 is defined. This computation domain is surrounded by a perfect matching layer (PML). The PML has 10 layers (detailed parameters regarding the PML can be found in the code framework).
A dielectric plate is placed at the centre of the computation domain as shown in Figure 1. The dielectric plate has a size of 500 𝑚𝑚 × 10 𝑚𝑚. The relative permittivity of the dielectric plate is 10 and the conductivity is 10 S/m. Two slits are added on the plate as shown in Figure 1. The distance between one slit and the origin of the computation domain is 78 mm.
An ideal current line source is placed at the position of (−150 𝑚𝑚, 0 𝑚𝑚). The current line source is propagating a 𝑇𝑀𝑧 wave. The source signal is composed of a wideband Gaussian pulse with 10 dB bandwidth from 0 GHz to 20 GHz. The source waveform is provided in the given codes.
TASKS
Task I: Please build the 2D-FDTD code to simulate the wave propagation in the simulation configuration shown in Figure 1.
Task II: Please show the 𝐸𝑧 field distribution in the frequency domain at the frequency of 9.3 GHz for the entire computation domain.
Task III: Please record the time-domain signals on a line located at 𝑥 = 200 𝑚𝑚 (indicated by the red dashed line in Figure 1). Please show the recorded time-domain signals at the 570th time step, the 575th time step, the 590th time step, and the 600th time step.
Task IV: Please record and show the frequency-domain signals of 𝐸𝑧 field at the frequency of 9.3 GHz on a line located at 𝑥 = 200 𝑚𝑚 (indicated by the red dashed line in Figure 1).
Please provide your MATLAB (or any other programming language) code with detailed comments. Marking Criteria for the codes (65%):
Components Weight Structure of the codes 15%
Parameters 30% Comments 15% Results 40%
Requirements for the report (35%):
Comments
Build the correct structure of
the 2D-FDTD algorithm
Perform correct calculations
for the parameters
Have detailed comments for
the developed codes
The developed codes can
produce the correct results
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Basic introductions of the double-slit experiment and the 2D-FDTD
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Relevant math formulations and corresponding illustrations
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Flowchart of your codes
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Pseudocode of your codes (for the format of pseudocode, please refer to
https://en.wikipedia.org/wiki/Pseudocode)
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Some screenshots of the results from your codes (for example, you might screenshot the electric
field distribution at different time steps, the 500th time step, the 550th time step, the 600th time step,
etc)
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Conclusion and inspiration from the results of your codes. Some physical interpretation can gain
your additional marks!
