HFSS Coax to Waveguide Transition (Ka band)

[imtiaz369]

Hi, I am working with an Coax to waveguide transition for Ka band with a 2.92mm end launcher, I have created the 3-D model in HFSS and also specified the required dimensions for the inner and outer cylinder for the coax . After simulation the the S-parameters are not what I am looking for. It should be -10 dB for the entire band as the waveguide is WR-28.

I want to know whether I have simulated the design correctly or am I making some trivial mistake?

I tried to adjust the pin depth and position but not get a good match! Port impedance is 50 ohm. I used wave port for coax port which provide 50 ohm and other side is also a wave port.

Can anyone please help me solve my problem?

Please let me know what all details do you require, I will provide all the details required.

Thank you.

 

[Kobba]

Hello,

If you want to achieve a wideband design you should consider adding more tuning elements to your design. Try varying the pin radius as well as its length. You could also include some steps in the waveguide. It might also be worth investigating and end-launcher type of design to see if you can get a better performance. Essentially by adding more tuning elements you will have more variables to optimize to find a solution.

 

[volker@muehlhaus]

The homemade transitions that we used at the university lab had an extra section of larger diameter at the center pin, similar to this:

Regarding trivial mistakes: have you tried to have only the center pin extend from the coax section, without the surrounding dielectric?