Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Microstrip electrical length

Microstrip electrical length

Microstrip electrical length

Hi, we are setting up a incoming inspection test for an antenna.  We will be checking VSWR using a HP4291A Impedance Analyzer.  We have created a fixture and I deisnged a microstrip that goes in the fixture to connect the antenna to the HP4291A.  

We need to know the electrical length of the microstrip that I designed.  The texts that I used as reference to design it only mention Effective Length while using a transmission line model.  Is the Effective Length the same as the electrical length?

Anyone know a procedure for measuring the electrical length of a microstrip?


RE: Microstrip electrical length

The electrical length changes with frequency for microstrip. Higher frequencies are electrically longer or they travel slower. Normal measurement of length is from a vector network analyzer where you calibrate S21, then hook up your cable and measure in time domain mode how long the effective pulse takes to get to the other port. Using the time domain feature of the analyzer can get you the amount of electrical delay in the microstrip. But if your antenna (or material being tested) is wide bandwidth, then the time it takes the energy to travel changes with frequency. Alternately, after you calibrate for S21 and attach your item there is a button on the display to add "electrical delay" length to the test result. Measuring phase you can set this electrical length value to make the phase read zero degrees and then just reading the value you entered into electrical delay. Look up "electrical delay" in the Agilent/HP manuals.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close