PCB design help for a project

[Sashvat]

C1 is a capacitor and C2 is just continuous track rather than a gap and capacitor.

Note that the track size, lengths between cap and antenna pad, spacing from that to the ground plane either side and ground plane cutouts on both sides are absolutely critical for it to work.

The drawings in the specification document are better; you need the dimensions as on page 8, but for 2.4GHz only you want to use the three connection arrangement as in the left diagram on page 9.

https://www.molex.com/pdm_docs/ps/2119640001-PS.pdf

Note that item is a bare antenna for a WiFi or Bluetooth device - it cannot connect to an MCU, only a device with built-in 2.4 GHz RF system and stripline connection.

Thanks rjenkinsgb, the ESP32 PICO D4 has a built in bluetooth chip, SoC, so I think it wouldn't be a problem to just directly connect to it. Because I have seen some schematics do it. Ex- https://dl.espressif.com/dl/schematics/esp32-pico-kit-v4_schematic.pdf

I hope I have done my schematic right. Also I am a bit confused with what the yellow and green colours on the board are. What are they?

Regards Sashvat

 

[rjenkinsgb]

See the PCB layout info in section 3 of the Hardware design manual:

https://www.espressif.com/sites/default/files/documentation/esp32_hardware_design_guidelines_en.pdf

You could just replicate the PCB antenna, filter, connections and layout used in the ESP32 PCB modules, as shown in that document.

In the antenna diagrams, yellow is copper and green is no copper.

 

[Sashvat]

C1 is a capacitor and C2 is just continuous track rather than a gap and capacitor.

Note that the track size, lengths between cap and antenna pad, spacing from that to the ground plane either side and ground plane cutouts on both sides are absolutely critical for it to work.

The drawings in the specification document are better; you need the dimensions as on page 8, but for 2.4GHz only you want to use the three connection arrangement as in the left diagram on page 9.

https://www.molex.com/pdm_docs/ps/2119640001-PS.pdf

Note that item is a bare antenna for a WiFi or Bluetooth device - it cannot connect to an MCU, only a device with built-in 2.4 GHz RF system and stripline connection.

right, the ESP32 PICO D4 has a built in bluetooth and wifi chip, so then it would be fine to directly connect?

 

[rjenkinsgb]

so then it would be fine to directly connect?

Not quite directly.

According to the data / examples, the ESP32 requires a "PI" section filter on its output. You would need to incorporate that, and the antenna matching components, all laid out using the correct track width for impedance matching.

I'd expect you would get a lot better results just doing an exact copy of the ESP32 PCB antenna, if a bit larger PCB area is not a problem.

 

[Sashvat]

Not quite directly.

According to the data / examples, the ESP32 requires a "PI" section filter on its output. You would need to incorporate that, and the antenna matching components, all laid out using the correct track width for impedance matching.

I'd expect you would get a lot better results just doing an exact copy of the ESP32 PCB antenna, if a bit larger PCB area is not a problem.

Well that is my problem, I am trying to keep this as small as possible. And when you mean copy the ESP32 PCB antenna, I am not quite getting what you're saying. Should I add the exact same inductor or does something else needs to be done?

 

[Sashvat]

See the PCB layout info in section 3 of the Hardware design manual:

https://www.espressif.com/sites/default/files/documentation/esp32_hardware_design_guidelines_en.pdf

You could just replicate the PCB antenna, filter, connections and layout used in the ESP32 PCB modules, as shown in that document.

In the antenna diagrams, yellow is copper and green is no copper.

Hi rjenkinsgb, can I directly add the same inductor as shown in the schematic?