Ceramic Chip Antenna Design with the ESP32-S3FN8
Posted: Mon Mar 18, 2024 12:14 pm
I am a hobbyist. I have made an application specific board with the WROOM-1 N16 variant, but decided that while making a revision to add features, I would switch to the ESP32-S3FN8 to save cost on board manufacture, and to get used to the process of setting up antennas as not all MCUs are as convenient as the ESP32 line modules that have antenna options sorted out for you.
It has.. not been straightforward.
I am hoping to get borrow the intuition and experience of those who have more insight into this process to determine what my next steps will be and have included some reference photos to aid in showing where I am now.
For sources of information I am reviewing quite a few references such as the hardware design guide, technical documents, datasheets etc, but one thing I am not really able to gleam from any of those sources is a rough feeling for how likely it is for my initial board to have its connectivity function prior to tuning. This is the main area where I would really appreciate some insight from those experienced with chip antennas/Expressif.
I, from reading various sources have gained the general idea that I am liable to have decreased performance without tuning and terrible performance/no performance at all without following design guidelines, but I am trying to piece together whether it is a reasonable endeavour at all as for me, I would consider "working somewhat reasonably" as an acceptable outcome and do not need it to be perfect out of the gate as figuring out how to use a VNA etc can come down the road.
Initially, my plan was to simply use impedance matching calculations to create a coplanar wave guide with ground plane with a calculated 50 ohm characteristic impedance at 2.4GHz and have that go directly to the antenna from the LNA_IN pin, where I would simply follow the manufacturer's advice for matching the cable to the antenna with a 6.8nH inductor/choke in this particular instance with the Walsin Tech Corp RFANT3216120A5T.
After seeing mixed opinions on how likely it was to have a working radio setup without tuning, I am now hesitant to go that route and feel perhaps I should add a PI Filter/CLC.
On the one hand, I read that PCB antennas are much more sensitive to noise/would necessitate this filter more than CHIP antennas, but on the other hand, the documentation seems to state that I should have one regardless (though it is in reference to a pcb antenna).
My question for I suppose any Espressif employee who is knowledgeable about this or any person who has used chip antennas in their board designs how right or wrong my intuitions are here, and whether I definitely need to include a PI Filter/CLC for tuning and get a VNA or if I am probably reasonably safe just having a matched transmission line based on calculations to get reasonable enough (functioning) connectivity.
Lastly, I was hoping to know if my board image of the relevant section of my board layout looks like I am on the right track with regards to the coplanar wave guide with ground plane transmission line.
Relevant images are included below.
It has.. not been straightforward.
I am hoping to get borrow the intuition and experience of those who have more insight into this process to determine what my next steps will be and have included some reference photos to aid in showing where I am now.
For sources of information I am reviewing quite a few references such as the hardware design guide, technical documents, datasheets etc, but one thing I am not really able to gleam from any of those sources is a rough feeling for how likely it is for my initial board to have its connectivity function prior to tuning. This is the main area where I would really appreciate some insight from those experienced with chip antennas/Expressif.
I, from reading various sources have gained the general idea that I am liable to have decreased performance without tuning and terrible performance/no performance at all without following design guidelines, but I am trying to piece together whether it is a reasonable endeavour at all as for me, I would consider "working somewhat reasonably" as an acceptable outcome and do not need it to be perfect out of the gate as figuring out how to use a VNA etc can come down the road.
Initially, my plan was to simply use impedance matching calculations to create a coplanar wave guide with ground plane with a calculated 50 ohm characteristic impedance at 2.4GHz and have that go directly to the antenna from the LNA_IN pin, where I would simply follow the manufacturer's advice for matching the cable to the antenna with a 6.8nH inductor/choke in this particular instance with the Walsin Tech Corp RFANT3216120A5T.
After seeing mixed opinions on how likely it was to have a working radio setup without tuning, I am now hesitant to go that route and feel perhaps I should add a PI Filter/CLC.
On the one hand, I read that PCB antennas are much more sensitive to noise/would necessitate this filter more than CHIP antennas, but on the other hand, the documentation seems to state that I should have one regardless (though it is in reference to a pcb antenna).
My question for I suppose any Espressif employee who is knowledgeable about this or any person who has used chip antennas in their board designs how right or wrong my intuitions are here, and whether I definitely need to include a PI Filter/CLC for tuning and get a VNA or if I am probably reasonably safe just having a matched transmission line based on calculations to get reasonable enough (functioning) connectivity.
Lastly, I was hoping to know if my board image of the relevant section of my board layout looks like I am on the right track with regards to the coplanar wave guide with ground plane transmission line.
Relevant images are included below.
- pcb_calculator_W9OU2kLdUT.png (71.66 KiB) Viewed 1859 times
- kicad_NFhKDadpbs.png (301.23 KiB) Viewed 1859 times