Learning Forum

[Steven Halls]

Hi All,

Sorry for the long post, but I only have the academic licence, so this is the only place I can ask for support.

I am attempting to adapt this tutorial,

,which demonstrates how a dieletric lens can focus a source, to this publication https://www.mdpi.com/2411-9660/3/2/28/htm , which involves the use of a 3D printed hyperbolic (Polyactic Acid) PLA lens. More specifically, I am trying to design my own cylindrical hyberbolic lens to "focus" the emitted radiation but only in a single axis. I am attempting to use the same HFSS + SBR combination used in the youtube tutorial since modelling the lens using HFSS alone is too computationally intensive. The issue I am having is that rather than focusing my beam, my lens appears to be reflecting most of the radiation backwards. Below is a screen shot of the radiation pattern of the transmitter without any additional lenses.

  

 

Below is a screen shot of the lens system and the corresponding radiation pattern. I created the lens in a separate 3D CAD programme and imported it into Ansys EDT.

 

For the PLA material I am using the Ansys PLA from the materials editor and the operational wavelength of the system is 77 GHz.

I have even tried a simple 3mm thick flat sheet of PLA to try and examine the attenuation caused by the PLA material. Below is a screen shot of the system and the radiation pattern.

Notice how, even when using a thin flat sheet of PLA the radiation pattern is very similar to that of the PLA lens, implying that even a small amount of PLA will simply reflect the incident radiation rather than focusing it.

 

I am new to Ansys so any help is greatly appreciated.

[Praneeth]

 

Hi Steven,

Thank you for reaching out to us and we appreciate your patience. 

I have some observations based on your post – 

 

1. Is the antenna source placed at the focal point of the lens?
2. What are the material properties of PLA that you are using?
3. The top surface of the lens appears to be faceted. Is this intended?
4. Did you take care of the reflections of the lens falling on the source?

Kindly check these to see if you can get improvement in your results.

Best regards,
Praneeth.

 

[Steven Halls]

Dear Praneeth,

Thank you for your response. To answer your questions;

1. Yes, the lens is using a 10x Lambda design, so at 77 GHz the lens is 38.9 mm away from the antenna.
2. The material properties are shown in this image.

3. No, I believe the faceting is a result of importing the mesh from an external modeling program.

4. Yes, I believe so. As part of the process of importing the antenna I enabled model blockage (as shown in the screen shot)

for the surface on which the antenna is mounted.

 

 

[Praneeth]

Hi Steven,

Sorry for the delay in my response. 

I am not sure what you mean by exporting mesh in point 3. You would have imported the CAD model from an external source, right? Also, you have mentioned that the flat lens results are not as expected. I doubt that the setup is not fully correct. To troubleshoot this, please raise a service ticket in the Ansys customer portal as this cannot be done in this forum.

Best regards,
Praneeth.

[Steven Halls]

Dear Praneeth,

Thank you for your response. Please be aware that as stated in my original post, as well as in other posts on this forum, users on the academic licence physically cannot raise tickets on the Ansys customer portal. We are entirely restricted to answers posted on this forum. Regarding point 3, you are correct. I imported the lens model into Ansys Electronics Desktop from Autodesk Inventor.

Sincerely

Steven