probe-fed patch antenna (IE3D problem!)

[Chest]

Hi there,

I'm using IE3D to do simulation in rectangular patch antenna. I'm faced some problem which is modelling of an probe-fed patch antenna with infinite ground plane. I'm cannot place the feed point to the patch. And i'm checked the IE3D manual that have not this example, only infinite ground. So below is my results and manual example. Please, anyone can help me to figure out my mistake.

Thanks in advance.

simulation result

IE3D manual

 

[jian]

Hi, Chest:

From the look, it seems that it is modeing a finite ground patch in the manual while your built is modeling a patch on infinite ground. In order to make it finite ground, you need to define the No.0 layer's conductivity to 0 or some very small value, and put some polygon(s) to represent a finite ground before you build the probe feed.

Best regards,

 

[Chest]

Hi, Jian:

Yup, I'm want to model a patch on infinite ground. Is it possible to make it? This is what I'm facing now. Thanks in advance.

 

[jian]

Hi, Chest:

Then, you should define the No.0 substrate as Conductiivty = 5.8e+7 or some value similar. Remove the polygons on z = 0 and build a probe from z = 0 to the patch level.

Best regards,

 

[Chest]

Hi, Jian:

I'm sorry for my slow learning. I had defined the No.0 substrate as Conductivity = 5.8e+7 as you request. And I'm did not place any finite ground, so I did not removed the polygons on z = 0. I built a probe from x = 0.55 to the patch. Then vertex snap at probe to edge. But what I done is only one vertex snap right and down. Do I done correct?

Thanks a lot.

 

[jian]

Hi, Chest:

The layout looks correct.

Best regards,

 

[Chest]

Hi there,

Before running simulation, it pops up

Actually, What is this mean? Thanks.

 

[jian]

Chest:

This is ok. It is just some message to you. IE3D users the polygons and vertices to do the meshing. If you have 2 vertices close to each other, IE3D may create a cell with tiny area but not tiny length. To the extreme, such a cell may cause numerical instability. IE3D gives you a warning on small edges formed by 2 vertices. If the value between the sign "<" do not differ by an order of 3, you normallly don't need to worray bout. If the "a < b" and a is 3 order smaller than b, you may want to select NO and IE3D/MGRID will indicate where it happens and you may want to check why. In most cases, there might be accidentally some inserted vertex there. You just need to select them and remove them. Certainly, you can use ADV EDIT->REMOVE REDUNDANT VERTICES ON CURVATURE command to remove those unneccesary vertices to improve the meshing.

For your case, believe a is basically the size of your probe, and a is about the same as b. You don't need to worry about it. The value b is automatically determined. We just want to give you a warning on it so you understand there will be small cells created.

Best regards,