×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Measurement of S-Parameters

Measurement of S-Parameters

Measurement of S-Parameters

(OP)
In a measurement setup why does the S21 parameter have a 2 in its equation (ie. S21 = (2V2/VG1) ) ?

RE: Measurement of S-Parameters

S21 is the forward voltage gain of a two port network when the input and output ports are matched to the system characteristic impedance. S11 is the input reflection coefficient. S22 is the output reflection coefficient . S12 is the reverse voltage gain. If the device is a linear passive network it will be symmetrical so that S21=S12. If it is an amplifier or some other directional device then the two gain figures are definitely different.

There is no global x2 factor in the definition of S21. It could be that any particular setup requires a x2 factor as a scaling because of an attenuator or some such thing.

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!


Resources