HFSS circular patch resonator filter with perturbation

Hellu,

Did anyone have experience in designing a circular patch resonator filter with slots using HFSS?
I did search everywhere but couldn't find any example with HFSS. I found many papers designing circular patch with slots, however no detail explaination on how to create the slots on the patch using HFSS.
PLEASE FIND THE EXAMPLE BELOW:

Hi zam_nmn,

I'm not sure what you're asking, are you inquiring as to how to make the geometry in HFSS?

Hello PlanarMetamaterials,

I need to know how to model the circular slot as per attach photo in HFSS, I did try using substract (which is the circular patch substract perturbation), however my response doesn't change. I also want to know how is the exact way to calculate the radius of slot in mathematical way. I really need an example tutorial on slot/notch creating on a patch using hfss to understand better.
I have another doubt, may I know how can I calculate the width and length of the 50 ohm feeding line if I am using suspended stripline?

Hi zam_nmn,

If your response didn't change after subtracting, most likely your simulation is not properly converged. Have it do extra adaptive passes and see if anything changes. I'm afraid I can't help you with the math of this, but google is your friend - there is a good HFSS patch tutorial at EMTalk. There are many free transmission line calculators on the internet, again google helps here (or a good microwave textbook such as Pozar).

Good Luck

Hello PlanarMetamaterials,

Thanks for your thoughts. Yes I did found the way to find the dimensions of transmission line and right now I am struggling to get the best response.
I am also trying to figure out how to add 135degree perturbation(hole circle to make it dual mode) from feeding line using HFSS. I did try with my design, but nothing was changed even though I vary the radius of the perturbation. If you have example project of using slot/notch in the design, do you mind to share with me?

Thanks a bunch!

Hi zam_nmn,

Unfortunately I don't have a design for you. I would still maintain that if nothing changes, the simulation is not adequately converged. What is your convergence criteria?

Hello PlanarMetamaterials,

I am sorry but I need to ask what do you mean by convergence criteria?
by the way, here is my attached response with too many spikes

, do you have any idea how to improve the response? my operating frequency is 1.8GHz.