I have a 2 layers PCB that I mount a Wi-Fi module. Components (SMD) are placed on the bottom layer and the Wi-Fi module is on the top layer.

I apply ground plane on both layers, as I read, it is good for the EMC compatibility. I know multiple layer design is even better, but now I need to have only 2 layers design.

I wonder if the ground plane might interfere or disturb the RF signal or block the signals coming from the other part of the board?

In this sense, is it fine to keep the ground plane on the both layers or make some holes on the PCB to prevent Farady's cage kinds effects?

Edit: here is the link of datasheet of the WiFi module http://www.zcomax.com/embedded/ZCN-722M/ZX-ZCN-722M-DS.pdf but it is a very simple one

  • \$\begingroup\$ It depends on the wifi module. Please link a datasheet. Usually ground planes under the modules are not good. \$\endgroup\$ – HL-SDK Feb 4 '14 at 19:08
  • \$\begingroup\$ @HL-SDK, please see the link above. \$\endgroup\$ – Angs Feb 4 '14 at 19:15
  • \$\begingroup\$ @angs - the detail is weak on how to mount it onto another circuit board. Maybe, for more answers you might do some digging around to find out what other documents there are? \$\endgroup\$ – Andy aka Feb 4 '14 at 20:12
  • \$\begingroup\$ If your "ground plane" has other tracks in it, it's not a plane, and very likely isn't doing anything to improve EMC - it may in fact make it worse. Research "slot antenna". \$\endgroup\$ – Phil Frost Feb 4 '14 at 23:29
  • \$\begingroup\$ @angs Maybe you can post a capture of the PCB Design. It much easier reply with that information \$\endgroup\$ – Jesus Castane Feb 12 '14 at 9:48

This is a 2014 post, but I just run into it. I cannot view the datasheet link for the wifi module, but I'm working on a design using BLE module (Silabs BGM111). On manufacturing datasheet, the layout recommendation should also apply to a wifi module. To answer the original questions, I don't think copper would block signal completely, but it will degrade the signal strength. Depending on your module antenna design, this copper/plastic clearance in 3D space can be different as well.

Module Layout

  • \$\begingroup\$ The metal doesn't just block the signal in some directions, it also de-tunes the antenna. All manufacturers will give layout guides as you included above, these list minimum clearances and often recommended clearances. Stick to them. \$\endgroup\$ – Andrew Nov 23 '16 at 9:17
  • \$\begingroup\$ Agree. I think this is the only way to guarantee RF performance as specified by manufacturers. By de-tuning, do you mean that there will be more signals loss? I'm not an RF engineer, so this is a new topic for me. \$\endgroup\$ – wildwildwilliam Feb 7 '17 at 18:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.