Learning Forum

[Aakriti Srivastava]

I am plotting twin rod TDR with respect to different distance of radiation boundary from the structure and getting different result. Is there any relation between radiation boundary and impedance calculation? Please let me know.

[Praneeth]

Hi Aakriti,

Thank you for reaching out and your patience is much appreciated.

Kindly provide more information to help us serve you better:

1. Which solution type you are using in the HFSS design type?
2. Is the radiation boundary assigned to a box object or to an open region?
3. Why you want to vary distance from radiation boundary distance from the structure?

The minimum distance between the radiating element and the radiation boundary should be at least quarter wavelength.

Please provide screenshots of your model setup and you can also use tags which helps in providing faster response.

Best regards,
Praneeth.

[Aakriti Srivastava]

I am using HFSS driven terminal solution type.

Radiation boundary is assigned to the dielectric material surrounding the structure.

Actually with different radiation boundary distnace from the structure I was getting different value of characteristic impedance from the TDR plot. So was curious what should be the distance of radiation boundary from the structure.

Please find the screenshort for your reference and help me with distance of radiation boundary from the structure. 

My structure if simulation is twin rod in HFSS 3D and it is surrounded by the dielectric. 

 

Hope this make my question more clear. Thanks

[Praneeth]

Hi Aakriti,

The radiation boundary is implemented to abosorb any incident radiations and is best suited for normal incidence. This will only be effective if you ensure sufficient distance between the radiating element and the boundary. It is suggested to have atleast quarterwavelength distance between the two. I am wondering why you were using this boundary in your model.

Please let us know what kind of analysis you were trying to make:

1. Is your structure working like a radiation source upon excitation?
2. what type of excitation you are using?
3. do you want to vary the distance from the radiation boundary as part of your analysis?

Best regards,
Praneeth.