How to setup the airbox in HFSS for patch antenna with finite ground plane?

[tyassin]

Hi

If you have a patch antenna with finite ground plane. How to setup the airbox correct?

I have used minimum \[\lambda\]/4 as a distance to my antenna structure.
But lets say you have an antenna with a very small ground-plane and you still need the \[\lambda\]/4 as minimum distance. Then there is a gap between the antenna and radiation box.
Should this be filled with a radiation plane?

Hope this make sense

Thank you

 

[rfmw]

Re: Airbox in HFSS

"But lets say you have an antenna with a very small ground-plane and you still need the /4 as minimum distance. Then there is a gap between the antenna and radiation box. "


I don't see how you make a gap here. If you antenna is smaller, then your airbox/rad boundary) is smaller too -> less memory needed

 

[peleda]

Re: Airbox in HFSS

you do not really need a space between the bottom of your ground plane and the bottom face of the radiation box -

on the edges of the ground plane, you should definitely put the lambda/4 distance to the side faces of your radiation boundary. Well, not up to lambda / 4. For your patch antenna there might be radiation to the sides of the ground plane. Kinda like a parachute shape.

 

[tyassin]

Re: Airbox in HFSS

OK, but then you do not have radiation boundary around your structure. Will that not give an error in your results?

 

[peleda]

Re: Airbox in HFSS

you will, but the radiation boundary is useless on the face underneath the ground plane. Am I answering your question wrongly?

 

[Azulykit]

Re: Airbox in HFSS

You have several options and can use either radiation boundaries or a PML. Both have advantages.

The latest guidance from Ansoft is to use a PML and the set up differs slightly when the object touches the boundary vs. when it does not. Read the on-line help sections and if you need additional help call one of their application engineers.