How to get the dimension back for patch antenna after EM Optimation in IE3D?

Hi all,

How to get the dimension back for patch antenna after EM Optimation in IE3D?
I mean L=?, W=? . Thanks.

Hi, Chest:

There are 2 ways:

1. If you want to know the distance between 2 vertices or linking a series of vertices, you can just enter the vertices snapped to these vertices as if you are entering a polygon. Then, select INPUT->INFO ON LAST ENTRY to see the information. You can find the total path length and the absolute and relative locations of all the vertices. This is the way I normally use.

2. On the IE3D 11.5 or later, you have the Inforamtion Bar at the bottom. You move the mouse close to an edge on a layer, you will see all the information about the edge and the 2 vertices in the Information Bar window.

Regards.

Hi Jian,

Now I design rectangular patch antenna using quarter-wave transform for impedance matching. And now, I want to add the ground plane (5cm x 5cm) on it, but I cannot acheive it. Do you have any solution? Thanks.

P/S: I attached my file.

Hi, Chest:

I don't see serious problem in your structure. I tried the finite ground plane model on it. It is slightly different from the infinite ground model. The difference is mainly due to the fact you chose very thin substrate for 10 GHz. In fact, there might be 2nd order mode in the transmission line due to the thick substrate. Attached are the files and results. Regards.

Hi, Jian:

In my design, my resonant frequency is 10GHz. And it is acheived without ground plane, but after added with finite ground I cannot to get the exactly 10GHz. Although I did with optimization, the result is still same. Any advices, please tell me. Thanks.

Hi, Chest:

There are 2 problems in your finite ground model.

1. You put a polygon on z = 0 while you are still defining z = 0 as an infinite ground. By IE3D definition, the polygon becomes a slot on the ground.

2. You need to use differential port (+1, -1) between the feed line and the finite ground.

Attached is the corrected geometry. The result is almost identical to the one with infinite ground plane. For patch antennas, ground plane size does not affect the input impedance much. It is not true for some other types antennas. If the antenna has many 3D features, the ground plane size will be important. Ground plane size is also very important to slot antennas even they are low profile. The reason is that the field is not concentrated near the proximity of the main part of the antenna like a microstirp antenna.

Regards,

Hi, Jian:

Thanks your advise. May I know how to use differential port (+1, -1) between the feed line and the finite ground?

Thanks.

Hi, Chest:

I sent you an example. Please check it.

Basically, you have the trace on z2 and the finite ground on z1 = 0.

1. Please try to make an edge about the same size as the trace ont eh finite ground.

2. You try to define a port. Please focus the selection to z2 and define the port 1.

3. Please click the right mouse button to bring up a pop-up menu. Please select DEFINE NEGATIVE PORT. Focus the selection to z1. Then, select the edge on the fintie ground plane to define a -1 port on it.

best regards,