Course Syllabus 2013/2014
 
PDF Extract Anglais
Français
index
Module : EA101
Title :
Transmission lines
Number of hours :
Lecture : 8.00 h
Combined lecture and tutorial classes : 5.33 h
Practical work : 3.00 h
ECTS credits :
1.00
Teacher(s) :
RODES Francis - Responsible
Level :
first year module
Abstract :
After a presentation of the various phénomenons that rule the transmission of an electric sinusoidal wave on a transmission line, the objective of this module is to highlight the interest of a Smith Chart for the design of circuits that incorporates both distributed elements (transmission lines) and lumped elements. In order to reach this goal, the module is divided in three parts: The 1° part presents the properties of transmission lines driven by a sinusoidal waveform. To perform this presentation the following topics are successively considered: The physical principles, the establishment of the propagation equation, the line technologies, the reflexion phenomenon and the diverse applications: impedance transfer, realization of stubs, isolators, and decoupling…. The 2° part is dedicated to the Smith chart and its various applications: Chart construction, directions for use of the standard versions (positive, negative, extended), impedance measurement and impedance matching. La 3° part is a practical work (a project) that consists in designing microstrip lines and impedance matching networks with the help of the Smith chart and the software tool: ¨Smith Tool¨ from Ansoft Designer. The subject of the project consists in designing an impedance matching network to be inserted between a loop antenna and a 406MHz RF transmitter. The design constraints impose to realize the impedance matching networks on a Printed Circuit Board with microstrip lines eventually associated with lumped elements. In order to find the optimal solution, the following matching networks will be considered:
  • Transmission line and single stub matching.
  • Mixed matching by transmission line and lumped element.
  • Quarter wave transmission line and single stub matching.
  • Mixed matching by quarter wave transmission line and lumped element Finally, the matching network, that exhibits the best performances in terms of miniaturization, cost and manufacturing repeatability will be selected.
  • Plan :
    1° part: The transmission lines in sinusoidal regime
  • Definitions
  • Distributed line parameters
  • Equivalent electrical diagram
  • Transmission line equation
  • Infinite length line, characteristic impedance
  • Finite length line loaded by a finite or infinite terminal impedance
  • Reflexion coefficient
  • Lossless line
  • General expression of impedance
  • Impedance transfer
  • Relation between the reflexion coefficient and distance
  • Standing Wave Ratio
  • Expression of power transmitted by a lossless line
  • Characterization of transmission lines currently used in Electronic Engineering
  • Coaxial line
  • Bifilar line
  • Microstrip line

    2° part: The Smith chart and its applications

  • Introduction, generalities
  • Construction of the Smith chart
  • Representation of admittances in the Smith chart
  • Representation of negative resistances in the Smith chart
  • Construction of ISO Q circles in the Smith chart
  • Impedance to admittance conversion
  • Computation of the impedances or admittances of complex network of lumped elements
  • Computation of the input impedance and reflexion coefficient of a line loaded by a known impedance
  • Measurement of an unknown load impedance
  • Design of a shorted stub with the Smith chart
  • Design of an opened stub with the Smith chart
  • Impedance matching : generalities
  • Impedance matching with a transmission line and a single stub
  • Impedance matching with a quarter wave transmission line and a single stub

    3° part: Practical work (a project) that consists in designing microstrip lines and impedance matching networks with the help of the Smith chart and the software tool: ¨Smith Tool¨ from Ansoft Designer.

  • Design of a microstrip line having a characteristic impedance: Zc = 50Ω
  • Check by simulation of the parameters of the 50Ω microstrip line.
  • Transmission line and single stub matching.
  • Mixed matching by transmission line and lumped element.
  • Quarter wave transmission line and single stub matching.
  • Mixed matching by quarter wave transmission line and lumped element
  • Selection of the matching network, that exhibits the best performances
  • Prerequisite :
      • Course: Electromagnetism
      • Course : ¨The electrical circuits¨
    Document(s) :
    Printed document: The transmission lines in sinusoïdal regime, the Smith chart Copies of PowerPoint présentations :
  • The transmission lines in sinusoidal regime
  • The Smith chart
  • Applications of the Smith chart
  • Keyword(s) :
    Transmission lines, microstrip line, Smith chart, negative Smith chart, extended Smith chart, impedance matching
    Online course :
    Copies of PowerPoint présentations :
  • The transmission lines in sinusoidal regime
  • The Smith chart
  • Applications of the Smith chart
  •