Patch antenna using PLM and an infinite ground plane.

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Subby

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Hi all,

I'm having an issue simulating a circular microstrip patch antenna over an infinite ground plane using a PLM boundary to keep the simulation space size small. Here's what I am seeing:

I have a box of air that defines my problem space with the bottom of the box co-planar with the bottom of my antenna's substrate material. I select the bottom face of the box and set the boundary condition for that face as a 'Perfect E Boundary' with 'Infinite Ground Plane' checked, forming the 'IGP' boundary.
I then select the remaining 5 faces of the air box and start the 'PLM Setup Wizard...' and define them as PLM using the default values for sizes, which creates the 5 PLM boundaries named 'PLM_radiation_1' thru 'PLM_radiation_5' where 'PLM_radiation_1' is the top of the air box and 'PLM_radiation_2' thru 'PLM_radiation_4' are the four sides of the air box. It also creates multiple 'PLM_Air_Box_x' boxes around my air box boundary, as expected.

When I run the Validation Check tool I get the following WARNINGS:

[warning] PML cover object 'PML_Air_Box_2' has a side face that contacts boundary 'IGP', but the boundary condition is not also on the PML object.
[warning] PML cover object 'PML_Air_Box_3' has a side face that contacts boundary 'IGP', but the boundary condition is not also on the PML object.
[warning] PML cover object 'PML_Air_Box_4' has a side face that contacts boundary 'IGP', but the boundary condition is not also on the PML object.
[warning] PML cover object 'PML_Air_Box_5' has a side face that contacts boundary 'IGP', but the boundary condition is not also on the PML object.


which is correct - the bottom faces of these four PLM_Air_Boxes lie in the plane of my infinite ground plane boundary, IGP

Quesitons:
1) Are these an issue I need to worry about? I ask because I do get a convergence warning when I run the simulation:
[warning] Adaptive Passes did not converge based on specified criteria. (9:54:19 AM Jul 23, 2015)[/B]

2) After I create the PLM, do I then have to go back and manually change the bottom boundaries of these four PLM_Air_Boxes to be Perfect E Boundaries that are also infinite ground planes?

Any thoughts would be much appreciated as I can't figure out why I am getting these warnings and convergence issues.

I've attached the associated files, if needed.

Thanks
John
 

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  • 449_MHz_Antenna.hfss.zip
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