Impedance of couples lines by simulation

[Terrorhertz]

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.

 

[Manjunatha_hv]

even mode impedance s parameter

Hello Terrorhertz,

Try this AWR free utility TXLINE...
**broken link removed**
Download it & use for coupled microstrip or stripline impedence calculations...
see the attached picture...


---manju---

 

[snkhan]

simulation of a shorted line in sonnet

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

 

[maxwellian]

even mode impedance

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]

strip line impedance calculator hp mode

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]

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]

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.