ELEC-E4420 - Microwave engineering I, Lecture, 10.1.2022-17.3.2022

Topic outline

• Topic 2, Smith chart and impedance matching
  Impedance matching is a fundamental and very typical task in microwave engineering. It is important for several reasons: 1) maximum power is not delivered to the load if there is mismatching between the load and the transmission line (especially problematic in limited-power application such as mobile phones), 2) standing wave may cause the electrical breakdown and/or heating in high-power applications (e.g., base stations, broadcasting and radar systems), 3) some components (e.g., transmitters) may become unstable and start oscillating because of reflecting waves, 4) amplitude and phase errors in mismatched power division networks, for instance, in antenna arrays. The basic idea in impedance matching is to place an impedance matching circuit between the load impedance and the transmission line. The basic tool for designing impedance matching circuits is the Smith chart. Learning to think with the help of Smith chart improves intuition of the transmission lines theory and impedance matching problems. In this topic, we will first recap the Smith chart and then learn to design matching circuits based on 1) quarter-wave transformer, 2) lumped elements (L section) and 3) single-stub. A glance to impedance bandwidth issues and multi-resonant matching techniques will be taken.
  

  The dedicated intended learning outcomes of Topic 2 are:
  

  • The student can design impedance matching circuits using the Smith chart and a simulator tool (AWRDE).
    
  • The student is able to explain the design principles and bandwidth issues related to impedance matching.

  
  

  In this topic one should command the following subjects of the course book:

  • The terminated mismatched load impedance (Chapter 2.3)
  • The Smith chart (Chapter 2.4)
  • The quarter-wave transformer (Chapter 2.5 and Chapter 5.4)
  • Matching with lumped elements (Chapter 5.1)
    
  • Single-stub tuning (Chapter 5.2)
  • The Bode-Fano criterion (Chapter 5.9)
    

  
  

  You will need the AWRDE simulation softwave in this topic. You can access the software through remote connection to Maarintie 8 computers via https://vdi.aalto.fi.
  

  
  

  • Select activity The Smith chart

    

    The Smith chart File PDF
  • Select activity The Smith chart (jpg)

    

    The Smith chart (jpg) File JPG
  • Select activity Interactive lectures take place on Thursday 27 Jan...

    Interactive lectures take place on Thursday 27 January and 3 February at 9

    
    

  • Select activity Slides of interactive lecture 1 of Topic 2 (27.1.)

    

    Slides of interactive lecture 1 of Topic 2 (27.1.) File PDF
  • Select activity Slides of interactive lecture 2 of Topic 2 (3.2.)

    

    Slides of interactive lecture 2 of Topic 2 (3.2.) File PDF
  • Select activity Preliminary tasks

    Preliminary tasks
    

  • Select activity Preliminary tasks of Topic 2 (DL 27 Jan & 3 Feb at 9:00)

    

    Preliminary tasks of Topic 2 (DL 27 Jan & 3 Feb at 9:00) Forum
  • Select activity Example videos

    Example videos
    

  • Select activity Video on lumped-element matching circuit design

    

    Video on lumped-element matching circuit design File MP4

    Example: Match the load impedance ZL=20+j 40 Ω with a lumped-element circuit to Z0=50 Ω at 1.5 GHz frequency.

    In addition to the courcebook chapter 5.1, this example may be helpful when solving Problem 1 of Topic 2.
    

    Duration is 17 minutes.
    

    33.6 MB · Uploaded 20/01/22, 18:54
  • Select activity Video on basic usage of AWRDE (lumped element matching circuit)

    

    Video on basic usage of AWRDE (lumped element matching circuit) File MP4

    In this video, the basic use (i.e., from scratch) of AWRDE is shown. The example is related to an earlier video on lumped-element matching circuits design).

    You can access the software through a remote connection to Maarintie 8 computers via https://vdi.aalto.fi.
    

  • Select activity Video on AWR and microstrip lines based matching circuit

    

    Video on AWR and microstrip lines based matching circuit File MP4

    In this video, microstrip line based matching circuit design is shown.

    
    

    Unfortunately, the "TX Line..." calculator window is not visible on the screen.
    
  • Select activity Exercise problems

    Exercise problems

    
    

  • Select activity Features of a good exercise problem answer and grading

    

    Features of a good exercise problem answer and grading File PDF

    Read this file carefully before completing the exercise problems
    

  • Select activity Exercise problems of Topic 2

    

    Exercise problems of Topic 2 File PDF
  • Select activity Exercise return session, February 7th

    

    Exercise return session, February 7th Scheduler
  • Select activity Exercise return session, January 31st

    

    Exercise return session, January 31st Scheduler