Need Help for HFSS Simulation for Patch Antenna With No Ground

Dear Friends,

I need help for a Patch Antenna simulation without a Ground Plane. Meaning that my substrate will not have a ground plane on bottom (Quasi Static) but the substrate will have the same height of a PCB 1.6mm.

What I have done is :-
- I have the antenna on top of the substrate.
- I have setup the Airbox for λ/4 and meshing for λ/10 as usual. Radiation Field been setup for the Box
- And I have lump port attached.
- And other setup for freq ext.

But I didn't define any ground plane on the bottom of the substrate. And I have Uncover the bottom Face of the Air Box.
- Antenna Resonance Freq is 910MHz , but I am not expecting anything on that Freq but I like to know what ever I am doing is Correct

Is my design is correct?, and I couldn't find any example without a Ground Plane. Is that correct to uncover the bottom Air Box?

Please Help and always appreciate your help. And I have attached my design in this post.

BRgds
Manimaran

Hello Manimaran

your antenna doesnt resonate at the desired frequency.Did you have a chance to check that? you should look at the dimensions of the copper in order to completely solve the resonance issues.

Its always Good to have the radiation cover everyside of the box.

apart from that everything else seems fine enough

Regards
Chachito.

hi
did u simulated the antenna base on a paper ????????
your radiation box is bot true and it should cover all part

Hi Ferdows,

Thanks for the reply. I didn't simulate based on paper, its on top of PCB (substrate). Why is there anything wrong? And I like to know what is the copper thickness to use, I used 0.035mm seems to be a bit thick?

Once again thanks for the help!

---------- Post added at 02:38 ---------- Previous post was at 02:32 ----------

Hi Rotmanlens,

Thanks for the reply, and I know my antenna is not radiating at the desired frequency. Currently I am using copper thickness of 0.035mm , is that ok if I change it to 0.0005mm, or what do you recommend?

And also like to know if, you change the sweep frequency, for what I have done is, I simulated from 100MHz to 3GHz, then I get results for S11 and then I changed the from 100MHz to 10GHz then I get another results of S11, both the results has some a little different values for S11, is that normal or is abnormal...did you experience the same problem?

Thanks again....
Manimaran

0.035mm = 35µm copper thickness is a typical value for FR4 boards.

Hello

You know the funny part when i looked at the convergence of the simulation,everything was converging in single pass,when i set the minimum number of passes to two it converges and then NA and then converges first and converges for the second pass.

and according to you the s11 values,no its just the change of scale i think not the actual results because i didnt see a big huge difference at all.

Regards
Sajid Mohammed.

---------- Post added at 12:05 ---------- Previous post was at 12:04 ----------

35um is 1ounce copper typical value of copper on FR4PCB

usually new FR4 substrate has 18um thickness but you dont need apply it into your simulation

ferdows said:

usually new FR4 substrate has 18um thickness

Click to expand...

Metal thickness has nothing to do with "old FR4" or "new FR4". You can choose the metal thickness, depending on your requirements.

ferdows said:

but you dont need apply it into your simulation

Click to expand...

It makes sense to include the conductor losses in simulation.