WLAN/WiFi (802.11b/g) and Bluetooth coexistence

[SCDesigner]

Hi, I am designing a board with both Bluetooth and WiFi and was wondering about the coexistance problem. I am aware of AFH and proprietary methods of TDM and/or FDM such as priority activity signalling and communication between each chips microcontrollers. As my design is at the physical level (not firmware) I was hoping for any tips on spatial seperation (distance, polarization, etc) methods to minimize interference between the two antennas. Board dimensions and layout currently limit the absolute distance between the two ceramic chip antennas to about 50mm. I have also tried to orientate the two antennas orthogonally so that each antennas minimum gain (referring to their datasheet) is directed towards the respective antennas. The ground plane making up the counterpoise for each antenna is currently connected along a long edge. I have used four rows of vias (at 1mm intervals) to try to isolate the RF energy in the two counterpoises. Will this work? Is it necessary? Also, with vias connecting the different layers of the counterpoise what is the recommended spacing/density if any. Any help with this antenna coexistence problem is greatly appreciated.

 

[Higgler]

A pictorial of your layout would help.

Normally, the higher frequency antenna pattern is harmed by the lower frequency one.

kch

 

[VEBill]

Aren't both 802.11 (b/g) and Bluetooth at 2.4GHz ?

Does any vendor make a combined 802.11 (b/g) and Bluetooth chip yet? That's the first thing I would check. One all-in-one chip, and therefore perhaps one antenna.

 

[zappedagain]

Here is an interesting article on Bluetooth and Wi-Fi issues in the Wii game system:

http://www.edn.com/blog/1690000169/post/520006052.html

Wow, I just got a link to this report as new news last week, but I see this search found it in December 2006. There may be a newer article out there.

Z