[SOLVED] Ansys HFSS help required.

[rxnr]

There are two main questions I have.
I have generated a patch antenna and am trying to optimize it using slots.
First thing I tried was using a U shaped slot. I didn't use any specific dimensions, just eyeballed it. And the S11 parameters and VSWR are good but I am unable to see the far field results. When I click on Radiation Setup, I get this popup.

I attached a full screen screenshot of everything I did is visible. Please do tell me what the mistake is.

Second thing,
I want to parametrize the dimensions of the u slot so I can get the best dimensions for optimum results. Any ideas on how?

 

[volker@muehlhaus]

I'm not an HFSS user, but see that you enclosed your antenna with perfect conductor (metal) side walls all around. You need to change this to absorbing PML boundaries, as mentioned in the message.

You mention that you already get good VSWR for the antenna inside the metal box - that indicates that you antenna is very lossy (FR4!) and only a small fraction of the input power is radiated. So expect to find poor antenna efficiency and low gain.

I can't help on parameters, but you should find lots of tutorials on that topic.

 

[PlanarMetamaterials]

Try creating the radiation boundary manually. Select the surfaces of the "RadiatingSurface" object and assign a radiation boundary. Then, define a far-field setup under the 'Radiation" title on the left.

You can create parameters easily by inserting text into your object defintions, in place of numbers. For example, you can define the X-axis length of a cube by replacing, e.g., "10mm" with "LengthX".

 

[vfone]

Right click on Radiation, Insert Far Field Setup, Infinite Sphere.
An option to add a radiation box is to go: Draw/Region and there choose "Pad all direction similarly" and Padding type, Absolute offset.
Then select "Region" and right click on Boundaries/Assign/Radiation...

 

[rxnr]

I'm not an HFSS user, but see that you enclosed your antenna with perfect conductor (metal) side walls all around. You need to change this to absorbing PML boundaries, as mentioned in the message.

View attachment 186378

You mention that you already get good VSWR for the antenna inside the metal box - that indicates that you antenna is very lossy (FR4!) and only a small fraction of the input power is radiated. So expect to find poor antenna efficiency and low gain.

I can't help on parameters, but you should find lots of tutorials on that topic.

Thank you for your reply. I managed to get far field results but like you said, my gain falls in the minus region.
Is it due to me using FR4? What are the changes you would suggest for better antenna performance?

 

[volker@muehlhaus]

my gain falls in the minus region.
Is it due to me using FR4? What are the changes you would suggest for better antenna performance?

Yes, these are the losses in FR4.
You need to use a substrate with lower loss tangent. Have a look at Rogers or Taconic substrate materials.

 

[rxnr]

Yes, these are the losses in FR4.
You need to use a substrate with lower loss tangent. Have a look at Rogers or Taconic substrate materials.

Thank you so much.