Electronic – Which material enclosure to avoid impeding signal of Bluetooth and wifi

Bluetooth operates in the 2.4 GHz band using 79 channels, spaced 1 MHz apart, from 2402 MHz up to 2480 MHz.

Bluetooth is less susceptible to jamming than Wi-Fi since Bluetooth uses a technology called Frequency-Hopping Spread Spectrum (FHSS). This means the signal "hops" from one channel to another, using a pseudorandom sequence known to both transmitter and receiver, 1600 times a second (every 625 µS).

In addition, Bluetooth also employs Adaptive Frequency-Hopping (AFH) which means it will only use "good" frequencies, and avoids "bad" frequencies, i.e. ones that are interfering with it.

So first of all, someone trying to jam a specific Bluetooth communication would have to be privy to its pseudorandom sequence, and then once the channel causing interference is detected, the jamming frequency would automatically avoided anyway.

Wi-Fi also operates in the 2.4 GHz band using 11 channels (in the US) spaced 5 MHz apart, from 2412 MHz to 2462 MHz. Because the bandwidth of a typical Wi-Fi signal is 20 MHz, assigning a Wi-Fi signal to a particular channel makes adjacent channels unavailable (for example, channel 6 will spill into channels 5 and 7, and a little into channels 4 and 8). So you can only get three non-interfering Wi-Fi signals in the same location: 1, 6, and 11.

Obviously, if you had a device that could jam the entire Bluetooth or Wi-Fi channels bands, such as this $5000 one, which is easier to jam is a moot point. But assuming you are trying to jam a much smaller bandwidth, since Wi-Fi uses fixed channels, it would be easier to jam Wi-Fi than Bluetooth -- since if one jammed an entire Wi-Fi channel (20 MHz), this would tie up 20 Bluetooth channels, but the AFH mechanism would allow the Bluetooth to avoid these and use channels that were not blocked.

Generally with an RF application, you want to tune higher or lower than the frequency you are trying to broadcast. Th surrounding material attenuation then matches with the proper operating frequency. In this case you can not do that, so the range will drop. I believe you will still be fine for a few feet of range after looking at the datasheet and seeing you can crank it to 10 dBm. This also depends on the thickness of the case material however.

If you can find a module (or want to make one) with external filter components then you can switch these out and tune according to the case. Hope this helps.