Attend Lab 3: Finite-Difference Time-Domain (FDTD)

  • Due No Due Date
  • Points 100

ECE 3305 Lab 3The Finite-Difference Time-Domain (FDTD) Method

Introduction

In this lab, you will program the Telegrapher’s Equations for a transmission line using the RLGC transmission line parameters. You will be able to see propagation of voltages on the transmission line, and reflections at faults or impedance discontinuities.

Pre-Lab: To make the most efficient use of your lab time, please complete the pre-lab readings and watch the videos.

Lab attendance: Lab attendance is required this week. Attendance by zoom will be an option this week, as no measurements are required.

No lab next week: Next week, there is no in person lab, and you can use that time to write your report.

What is due: The report for this lab is due  before your next lab.

 

PRE-Lab

Download Files for Lab 3

Please download the following files and bring them with you to the lab (preferably on your laptop).

REQUIRED PRE-Lab Videos / Readings

  • FDTD Videos (please watch before the lab, and return to them as needed as you work through it)

Supporting Material (organized by section of the lab)

Motivation: Numerical Electromagnetics

Additional technical elective classes that might interest you:

I. Intro: FDTD for Telegrapher's Equations

  • See Ulaby textbook section 2-3 Transmission-Line Equations

II. RLGC Values of RG-58 Coaxial Line

In this section, you will find the RLGC values of RG-58 coax. This is the same as the code you programmed for Lab 1 (for RG-174 coax), but with different values.See Ulaby textbook Table 2-1 and Module 2-2.

Details on RG-58, including its data sheet, can be found here. Links to an external site.

FDTD Code template Download FDTD Code template.Download here .has these programmed already. Check to be sure you get the results you are expecting. (The code will run to the point these are calculated, but will have an error after that, because you haven't entered the FDTD equations yet.)

III, IV. Derivations: Difference form of Telegrapher's Eqns

V, VI. Programming

  • Video 4 above describes the algorithm.
  • FDTD Code template Download FDTD Code template. has almost everything programmed. Add the FDTD constants derived in section IV in the FILL IN HERE sections.
  • Remember RLGC are arrays, so use the Matlab .*  and ./  commands (dots in from of * and /) to perform these operations.
  • CHOOSE the size of the array maxZ, source type and source resistance  (These are marked with "CHOOSE" in the code template)
  • CHOOSE the boundary condition (only one is needed .. short, open, matched load).
  • The time step dt will be chosen based on stability criteria that are out of scope of this lab. Here's the derivation, if you are interested, but you are not required to understand it for this lab stability-analysis.docx Download stability-analysis.docx
  • CHOOSE the maximum number of time steps.

VII. Final Report

  • Lab 3 Handout Download Lab 3 Handout has several items marked with red italics. These are things you need to turn in. As noted at the end of the handout, this week we will be grading the writing of your short abstract (a succinct 1 paragraph that describes what you did in the lab).
  • Also turn in your derivations (scans of hand-written derivations are fine, but please make them clear to read),
  • and Matlab code, well commented.

Recommendations for writing a good abstract

TURN IN

  • Attendance is required, either in person or by Zoom. 100 points will be given for your attendance.
  • Turn in your report before your next lab:
    • Abstract
    • Derivations
    • Matlab code, well commented

 

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