I am working on an IoT project which using BLE (Bluetooth Low Energy). The Device Case is Metal Body. In our testing we have found that without the Metal Body the Device BLE is working absolutely fine and connecting with the Mobile Phone efficiently.

But as soon as we apply the Metal Case on the Device BLE stopped working or working only within 6-8 inches of range. BLE is not able to advertise efficiently after applying the metal case.

We are using Nordic BLE Semiconductor 51822. It has BLE 4.2.

MS 0.8 mm Metal used for the Case.

Can anybody suggest how to improve the BLE Advertising Range within the metal case?


  • 2
    \$\begingroup\$ The metal case is working as a Faraday cage and shields your BLE device. 1) You could move the BLE antenna outside the metal case. 2) Put a bunch of holes in the metal case, to break the Faraday cage. 3) Use a plastic case. \$\endgroup\$ – Peter Karlsen Mar 11 at 10:00
  • \$\begingroup\$ It reminds me of the early iPhone prototypes: Apple's designers didn't consider that radio waves do no pass through a mostly metal case. (cultofmac.com/488008/jony-ive-book-excerpt-iphone, search for "pass through"). \$\endgroup\$ – Codo Mar 11 at 10:04
  • \$\begingroup\$ Thanks @PeterKarlsen Actually the device is waterproof security device and we are unable to put the holes in it. Is there any other suggestion? \$\endgroup\$ – Sohan Lal Mar 11 at 11:02
  • 3
    \$\begingroup\$ Use a plastic case. \$\endgroup\$ – Brian Drummond Mar 11 at 12:51
  • \$\begingroup\$ Even holes would need to be pretty big for 2.4 GHz signals to get through correctly. As already suggested, either use an external antenna or switch to plastic. With a decent design you could have a case with both plastic and metal parts, but that needs careful consideration. \$\endgroup\$ – jcaron Mar 11 at 21:09

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