Don't place PCB antenna into middle of your board. Here is why .... | ESP32

See the difference between a module with PCB antenna placed in the middle of a board vs. at the edge. Thank you very much Katerina Galitskaya.
Other Links:
- Katerina's LinkedIn: / katerinagalitskaya
- FEDEVEL courses: fedevel.com/courses
Chapters:
00:00 What is this video about
01:08 What we will simulate
02:09 Antenna placement - what to think about
12:31 ESP32 module antenna simulation
19:11 Module placed in the middle of a board
24:06 Module placed at the edge of a board
41:01 About Katerina's job
43:32 Simulation setup
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Would you like to support me? It's simple:
- Sign up for online courses hosted on our platform: fedevel.com/
- You can also support me through Patreon: / robertferanec
- FEDEVEL Discord: / discord
It is much appreciated. Thank you,
- Robert

[@imagiro1]

One of the best and intended use cases for internet: Experts sharing knowledge with amateurs. Thank you Katerina and Robert, that was very interesting! Btw, if the antenna doesn't work properly, then you are holding it wrong 😉

[@zyghom]

I have used plenty of these ESP32 modules (not the develompent boards, but modules), but always the "I" versions: with extra socket on them for external antenna. This way I can put them wherever I want and any external antenna - even the one for 0.5$ - is better than the one on PCB. That is not calcuculated by me but empirically established by comparing RSSI for modules with PCB vs modules with external antenna. But I like this video so much - especially the part that shows that you lose 99% of the energy once you did it wrong way ;-)

[@erdling2454]

A small addition to Katerina's words: The “red donut” represents the E-field strength in the so-called far-field region of the antenna. For this type of antenna, with antenna dimensions smaller than λ/2 (electromagnetically short antenna), this region applies to distances greater than 2λ (λ: free space wavelength) from the antenna. In the far-field, the E- and H-fields are in phase, and the wavefronts can be assumed to be parallel. In most applications, the far-field indicates the relevant radiation behavior of an antenna. For more information, please refer to: en.wikipedia.org/wiki/Near_and_far_field Greetings from Germany.

[@TMinusRecords]

Very insightful! Everyone tells you not to but there's always the concern that it's just superstition or not really that important. Great to have real, practical data explained so well!

[@wraymogg]

First of all, thank you for all your videos and especially for this one. I repaired a lot of things in my designs after watching your videos, especially with Mr. Bogatin. This video is also one of them, I modified the position of the BT mini-board to take out the antena. The one about ferrite beads made me change something as well, and many more others. I love when you interrupt Mr. Bogatin and ask the questions than normal people, like me, will have... Keep up the good work!

[@electgpl]

Great video, in some cases the RF shield can be calculated to be part of metamaterial and improve the loss of efficiency due to lack of ground plane 1/4 of the length of the MIFA. They could make a video on metamaterials, it would be interesting. Regards!

[@alelondon23]

Thank you, Katerina, for the thorough and clear explanation. Very useful! Regards fron London town.

[@electronics.unmessed]

Very interesting! Thanks for sharing!

[@warperone]

loved this - thaks for doing and sharing

[@amirharsat2224]

Funny how I follow you two on LinkedIn regardless this video. Great video Robert

[@xx-mz2eg]

Interesting topic, I didn't expect to touch quite specific topics, to be honestly. I have one suggestion for future discussions -- how antenna designers tune antennas according to use cases? Example being phone -- one can speak with phone being close to ear and also one can speak with phone on table thru loudspeaker enabled. Is dynamic matching the answer or there are some techniques employed with passive components only?

[@saddimohamed]

merci pour cette vidéo c'est très instructif merci encore

[@harishadzic50]

What would you recommend as the best approach to learn more about antennas and RF in general? Especially for many of us who don't have access to expensive equipment or software simulators. Btw, great video, thanks a lot Robert and Katerina!

[@ricolauersdorf687]

Waaaaaooow! thank you so much for this!

[@AX-sq5vm]

This are fragile things I never thought about antina I just placed it where it fits perfectly and easy connection

[@ZoeyR86]

I hang the module off the edge. In one case, I put the module on the vertical pcb in the middle of the board that was socketed. I used a vertical m.2 connector

[@ahou3236]

Thanks a lot for these explanations! It helps me a lot integrating a BT840X module right now. When we speak about ground plane size, does the multiple layers add up? Like if I have 30mm behind my 2.4GHz antenna on a 4-layers board, will the 2 external layers add up and make 60mm length together? Can we also count the internal layers? My board has a BT840X and the module size is pretty small (compared to 2.4GHz wavelength) with large GND pads on its bottom layer near the antenna. On the board, there's a big ground plane on the side of the module but only 30mm right behind in the antenna direction like you show on your first illustration at the beginning at 2:42

[@katerinagalitskaya8948]

No, layers do not add up. What you want to have is just a proper length.

[@ahou3236]

@@katerinagalitskaya8948 ok thanks!

[@gcaricato]

Hi Katerina. In all your simulations I see poor return loss (S11 never below -10dB), even with the correct placement. I assume this is due to the inaccuracy of the model. Can we have a good radiation efficiency despite a high return loss?

[@katerinagalitskaya8948]

Your assumption is correct. The model was taken from an open library. We see it in the simulation- only 50% max efficiency, where it should be 90% or so. In real project antenna should be fine-tuned.

[@Ydooo]

what if you use a flexpcb?

[@CannonballCircuit]

Do you know why there are so many app notes that say a ground plane underneath the PCB trace antenna is required? I've always been confused by this because I never understood the logic of having a ground plane for a meandered trace antenna or a PIFA. Additionally, can you calculate the trace impedance of the antenna if there is no ground reference, or do you have to use simulation to figure this out?

[@katerinagalitskaya8948]

Some antennas (like patch antenna for example) require ground plane beneath them. However for omnidirectional radiation we must have keep-out area as said in the video

[@katerinagalitskaya8948]

PIFA (the antenna in the video) is roughly 1/4lambda in length. You can calculate lambda on your frequency of interest and get the antenna length. However, without simulation you will definitely need to fine-tune this antenna in a lab.

[@imagiro1]

around 45:10 , do I see that you cut off a bit of the antenna? So did you tune it for the purpose of this demonstration?

[@katerinagalitskaya8948]

I did cut it indeed! The 3D model was taken from an open library, so antenna was probably created without any thought behind it. I tuned it to work on 2.45GHz in the DevKit. All other cases use the same model/antenna

[@imagiro1]

@@katerinagalitskaya8948 I see! :) - Thank you again for your effort, more pieces of the puzzle that is Electricity fell into place!

[@maxsintar108]

Really interesting video. What would also be really interesting to know is how to increase the antenna efficiency? Because if, say, there is a shift in the frequency you can tune the L/C components or length of the PIFA antenna but that will not increase the efficiency of the antenna, right? When the simulation showed the efficiency of 50 percent in the standard ESP dev kit what changes would increase the efficiency?

[@katerinagalitskaya8948]

Ground plane size and right placement are the main contributors to efficiency in PCB antennas

[@maxsintar108]

@@katerinagalitskaya8948 Thank you very much for the reply

[@fedimakni1200]

I was surprised that the esp32 dev board already has 50% efficiency. but is it the module itself or the full board affecting that efficiency. If we use the module in another board can we improve it? and is that possible if we plan to use esp32 in a commercial device? thanks

[@katerinagalitskaya8948]

DevKit has a good ground plane size for a good efficiency. With some tuning work on the antenna, the efficiency would be higher. The 3D model was taken from a free library so the antenna was not done well. The model itself (not DevKit) will not have good efficiency as it is really small.

[@fedimakni1200]

@@katerinagalitskaya8948 so using the esp32 in a small pcb for commercial product will be a little horrible with this efficiency

[@katerinagalitskaya8948]

to maximise efficiency at 2.45GHz your PCB should be more than 50mm length with good antenna placement (edge or corner)

[@fedimakni1200]

What about chip antenna? Are they better than pcb antenna in term of their sustainability to frequency shifting?

[@katerinagalitskaya8948]

Custom PCB antenna is in 90% cases better than chip antenna. Chip antenna essentially works as described in datasheet ONLY on the reference board that is in datasheet (same size, same placement). If your PCB is different from the reference PCB of a chip antenna, it will behave differently. How differently? Hard to predict! Sometimes easy fine-tuning can help, sometimes no tuning needed and sometimes chip antenna stops working altogether

[@fedimakni1200]

@@katerinagalitskaya8948 thank you very much.

[@nameredacted1242]

It is better to not put an antenna in your crappy product.

[@fedimakni1200]

@@nameredacted1242 what's the purpose of your reply?

[@nameredacted1242]

@@fedimakni1200 Am I wrong? 90% of products with antennas do not need them.

[@MatsK007]

When Katerina is saying 2,5GHz module (1:20) i loose confident ...

[@nameredacted1242]

90% of idiots trying to put an antenna into everything have no clue about EMI compliance or certification.

[@JeromeDemers]

I realise you never let your guest introduce themself. Maybe try that next time.

[@r_be]

Nice observation. I am sure Robert will consider it. Now that you brought this up, I don't think it mentioned anywhere what the guest works as, type of industry that she is in, etc. Great video, nevertheless Robert!

[@RobertFeranec]

I always ask new people kzbin.info/www/bejne/rImWnWOfh92cbsU just keep in mind, some people don't want to or can't talk about what they do.

[@f33net]

That is, if the antenna is moved a couple of centimeters, its radiation will not get into the circuit in any way? I'm sorry, I couldn't watch the funny pictures carefully for almost an hour.

[@katerinagalitskaya8948]

It is more about the keep-out area around and beneath the antenna. The best possible location for a PCB antenna is on the edge or corner of a board with no ground beneath it.

[@rfengr00]

It’s on headers, so at least elevate it off the ground plane by that amount.

[@atanisoftware]

True, it will likely end up ~5mm above the base PCB. The fields that have been shown are a bit closer to what you might see with a bare module (not a devkit).

[@katerinagalitskaya8948]

The elevation might help a bit with radiation, as there will be some air between antenna and the ground plane. But it will create a cavity, which will resonate.

[@paulpaulzadeh6172]

Worthless, text so smal not readable . Put so much time for nothing, she should teach herself PowerPoint 😂😂😂😂

[@user-mm3yb9nn5p]

First part of presentation- Poor choice of colors for components! Brown should be copper not cir bd. Totally confusing. The narrator saves her so many times. She cannot get a clear explanation out. She appears knowledgeable but lacks the ability to clearly explain basic concepts or convey ideas.

[@gcaricato]

If you don't understand it doesn't imply it's the speaker's fault. It's very difficult to talk in a simple way about extremely complex topics. “Everything should be made as simple as possible, but not simpler”, said a wise man...

[@MrBPeet]

@@gcaricato Well... copper is usually presented by some yellow or goldish color and dielectric in green by default. In any design software. Why? Because exactly that is how 99% of actually fabricated boards look like. This video was not targeted for antenna engineers who already know everything as in that case why would they even bother to watch 52 minute long video? So most probably the target audience was a group of people who are not experts in electronics. In which case the speaker should take at least the minimal effort not to confuse the target audience by showing things in inverted colors and keep searching for proper words and intermixig words like yes, no, board, kit and module in the very same sentence. I mean if they care about their audince. If you are just beginning to learn photography and a photographer is showing negative images and trying to speak about the imprtance of light in photography...then maybe the fault is not in your novice skills, but probably you just did not find a person who takes care of putting his knowledge in a proper way.

[@DmitriyKhazansky]

Interesting video and subject. I wish the model simulation was more realistic in that no one is soldering the module onto their PCB, they use a header which places it ~10mm above the larger PCB. @katerina galitskaya - Curious to see how that would alter your simulations