connection of CPW and Microstrip line in Sonnet

[sirricky]

Hello everyone,
1. since the ground plane of microstrip line is in different layer with the center line, assuming the CPW line is in layer 1, the center line of microstip is also in layer1, and the ground of microstrip line is in layer2, how could I set the ports?
on the CPW side, I set as -1,1,-1 (GSG), but on the microstrip line side, how do I set the port? do I need to connect the differnet Gound line by vias?

2. I want to simulate the unload Q of a half wavelength microstrip line as a resonator in Sonnet. assuming the end is open. I do in this way:
set port 1 on one side of line, and in order to make the other side open, I leave a gap to the edge of the box. Then plot S11.
Is it ok?

 

[Joe_User]

sirricky,

1) There are quite a few different ways you could do this, but here is one way. If your microstrip ground is a polygon, then you can put a negative port on the microstrip ground. Just make sure it only touches the box sidewall where the port is and not the other box sidewalls. Otherwise the port will be shorted out. Also, you need to keep the bottom of the Sonnet box a long distance away (unless in real life this not the case).

There has been a lot of talk on the Sonnet Forum lately, which has a lot more detail and more cases than the one I mentioned above.

2) Regarding your resonator question, this sounds fine, just as long as you have some loss in your circuit (otherwise S11=0dB everywhere). If in doubt, make the gap closer and farther away and verify that the results do not change.

There is a really good paper by Dan Swanson which talks about this:
"Narrow-Band Microwave Filter Design"
IEEE Microwave Magazine
Oct 2007
He couples into the resonator on both sides (two-port).

 

[Manjunatha_hv]

Hello sirricky,


1.Their is a PDF document (EDABoard link is provided) which is a nice document on Modeling Co-Planar Waveguide (CPW) using Sonnet....Also their is an example available in Sonnet Examples folder (cosht_sy.son)...This helps you to analyse CPW structures using Sonnet...


and

2. The Box Dimensions are very important & you need to use exact implementation dimensions...Other wise upload your *.son or *.zon file here...
to comment on the same....


---manju---

 

[sirricky]

So nice!! Thank you all, I will have a look soon!