Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics 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.

Impedance of couples lines by simulation

Status
Not open for further replies.

Terrorhertz

Newbie level 3
Joined
Nov 3, 2006
Messages
4
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
UK
Activity points
1,312
simulating even mode impedance in ads

Can anyone advise me if they have had luck in simulating the odd and even mode impedances of parallel coupled stripline ( with a top and bottom ground plane as per stripline). CST gives values that I dont completely trust.

Are there any open source programs that use the method described in R. R. Gupta "Accurate Impedance Determination of Coupled TEM Conductors" IEEE MTT vol 17 No 8 August 1969

Any advice would be appreciated.
 

snkhan

Full Member level 6
Joined
Oct 19, 2005
Messages
324
Helped
38
Reputation
74
Reaction score
20
Trophy points
1,298
Location
Gods place
Activity points
3,213
simulation of a shorted line in sonnet

Download AppCAD utility, it was initially design by HP. Very good and reliable.
 

maxwellian

Full Member level 2
Joined
Feb 22, 2005
Messages
144
Helped
26
Reputation
52
Reaction score
8
Trophy points
1,298
Activity points
3,161
even mode impedance

Terrorhertz said:
Can anyone advise me if they have had luck in simulating the odd and even mode impedances of parallel coupled stripline ( with a top and bottom ground plane as per stripline). CST gives values that I dont completely trust.

Are there any open source programs that use the method described in R. R. Gupta "Accurate Impedance Determination of Coupled TEM Conductors" IEEE MTT vol 17 No 8 August 1969

Any advice would be appreciated.

I think maju's advice to get a transmission line caculator first is a very good idea. TxLine and AppCAD are both good transmission line calculators that provide coupled line models. That will get you close to a reasonable result.

To test the result for higher accuracy, you can get a free 3D planar EM simulator to build and test it. I would probably recommend Sonnet Lite, since they have really good ports, very deep dynamic range and are by nature a shielded domain simulator which is good for modeling striplines. In Sonnet Lite you can get the odd-mode impedance and S-parameters by setting the ports to 1 and -1 on one end and 2 and -2 on the other. Then, to get the even mode impedance and S-parameters, set the ports to 1 and 1 on one end, and 2 and 2 on the other.

Using this method should result in very accurate structures.

--Max
 

snkhan

Full Member level 6
Joined
Oct 19, 2005
Messages
324
Helped
38
Reputation
74
Reaction score
20
Trophy points
1,298
Location
Gods place
Activity points
3,213
strip line impedance calculator hp mode

maxwellian said:
I think maju's advice to get a transmission line caculator first is a very good idea. TxLine and AppCAD are both good transmission line calculators that provide coupled line models. That will get you close to a reasonable result.

To test the result for higher accuracy, you can get a free 3D planar EM simulator to build and test it. I would probably recommend Sonnet Lite, since they have really good ports, very deep dynamic range and are by nature a shielded domain simulator which is good for modeling striplines. In Sonnet Lite you can get the odd-mode impedance and S-parameters by setting the ports to 1 and -1 on one end and 2 and -2 on the other. Then, to get the even mode impedance and S-parameters, set the ports to 1 and 1 on one end, and 2 and 2 on the other.

Using this method should result in very accurate structures.

--Max


can you upload an example using sonnet free to show even and odd modes.
Thanks
 

Terrorhertz

Newbie level 3
Joined
Nov 3, 2006
Messages
4
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
UK
Activity points
1,312
polar simulation impedance

Thanks for the advice. TXline is good for coupled lines on the same plane, however, I did use CST with a short length of line (performing a port mode calculation only)and a very fine mesh to obtain good results.
 

Azulykit

Advanced Member level 4
Joined
Feb 18, 2007
Messages
1,121
Helped
219
Reputation
436
Reaction score
112
Trophy points
1,343
Location
All over the Map.
Activity points
8,407
Add Polar's Si9000 to the list of Zo calculators and also look at the on line help in HFSS on impedance calculation for guidance on setting up the calculation.

I also usually look at the fields at the port to make sure I have the mode I want.

good luck, it is easy to go astray.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top