Questions about trace antenna

RE: Questions about trace antenna

Juniorprogrammer — Wed, 30 Nov 2022 12:07:34 GMT

Update:

Sorry Kazi, but I think I did get it. In figure b the trace is routed to the edges. I think that is the reason to expand the length with 30%.

RE: Questions about trace antenna

Juniorprogrammer — Wed, 30 Nov 2022 09:50:28 GMT

Hi Kazi,

"Total ground plane."

In the papers of the monopole antenna I did read this:

So in figure B the total ground plane is lager than the antenna. But it says it have to be 30% extended.

Or do I get it wrong?

Br,

RE: Questions about trace antenna

Kazi Afroza Sultana — Wed, 30 Nov 2022 09:40:54 GMT

Hello JP

''Is this the total ground plane of the PCB or the ground plane under the antenna.''

Total ground plane.

''Is there a way to calculate it, so how?'' This is mostly simulated with computer tools. There is no direct method to calculate it. Ground plane, antenna shape determines the gain. It depends on your design. What is your exact plan? You may contact to antenna design companies like Fractus, Ignion or Johanson technologies.

Thanks.

Kazi

RE: Questions about trace antenna

Juniorprogrammer — Tue, 29 Nov 2022 15:19:45 GMT

Hi Kazi,

Firstly thank you for your reply.

[quote userid="108933" url="~/f/nordic-q-a/94328/questions-about-trace-antenna/398157"] it should be 10 cm or so. When a PCB size is small like 50mmx50mm,[/quote]

Is this the total ground plane of the PCB or the ground plane under the antenna.

[quote userid="108933" url="~/f/nordic-q-a/94328/questions-about-trace-antenna/398157"]It depends on the size of the ground plane. So based on the applications the design would be different. So, there is no specific number for this. [/quote]

Is there a way to calculate it, so how?

Kind regards,

RE: Questions about trace antenna

Kazi Afroza Sultana — Tue, 29 Nov 2022 14:49:39 GMT

Hello JP,

The ground plane of the PCB should be longer than the 1/4 of the wavelength; For example: if the band is 700 MHz, it should be 10 cm or so. When a PCB size is small like 50mmx50mm, it is difficult to get the proper ground plane. Then you need to do some adjustment to get the accurate signal strength. It could be changing the size of antenna, adding extra switches (you can look at our Thingy:91 design (https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/dev-kits/thingy91/hardware-files/thingy91---hardware-files-1_6_0.zip)) to tune the antenna in different frequency bands etc.

devzone.nordicsemi.com/.../Small-size-2_5F00_4GHz-PCB-antenna-_2800_2_2900_.pdf

I am attaching an application note of a 2.4 GHz PCB antenna for your understanding.

''And how much gain do I expect with this type of antenna?''

It depends on the size of the ground plane. So based on the applications the design would be different. So, there is no specific number for this.

I hope it helps. Feel free to ask more questions if you have.

Thanks.

Best Regards,

Kazi Afroza Sultana