Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

s-parameter has problem in cst

Status
Not open for further replies.

myjae

Junior Member level 2
Joined
Sep 26, 2013
Messages
21
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
136
1.jpg

i used lineimpedance macro.
right of the picture S1,1 & S2,2 is 16.39 ohm.
but smith position is not 16.39ohm.

why did happen this result?
 

BigBoss

Advanced Member level 5
Joined
Nov 17, 2001
Messages
4,913
Helped
1,489
Reputation
2,976
Reaction score
1,331
Trophy points
1,393
Location
Turkey
Activity points
29,621
Because you confuse Characteristic Impedance with Input Impedance of a Transmission Line terminated with 50 Ohm.
 
  • Like
Reactions: myjae

    myjae

    points: 2
    Helpful Answer Positive Rating

myjae

Junior Member level 2
Joined
Sep 26, 2013
Messages
21
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
136
Because you confuse Characteristic Impedance with Input Impedance of a Transmission Line terminated with 50 Ohm.
i'm not understand
so please let me know in detail
 

BigBoss

Advanced Member level 5
Joined
Nov 17, 2001
Messages
4,913
Helped
1,489
Reputation
2,976
Reaction score
1,331
Trophy points
1,393
Location
Turkey
Activity points
29,621
i'm not understand
so please let me know in detail
You calculated Characteristic Impedance of a Coaxial transmission Line.This impedance depends on physical parameters of coaxial line.( dielectric coefficient,inner and outer radius,conductor diameter etc.). But when you simulate this Transmission Line in a EM simulator you usually use 50 terminating impedance at the end of the Transmission Line and therefore Input Impedance of this transmission line seems different than characteristic impedance.If you calculate input impedance of a transmission line with a characteristic impedance different than 50 ohm, you will find approx. same value.Refer to EM text book.
 
  • Like
Reactions: myjae

    myjae

    points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top