I’m making an enclosure for:


I read that Bluetooth signal can be impeded by 37% by a plastic case. If that is so, then how does one design a case to protect the esp32 from dust , water , etc, without impeding the signal?

  • \$\begingroup\$ Wherever you've read that 37%, it's utter nonsense, or utterly taken out of context. That's not how any of this even remotely works. Any material interacts with electromagnetic waves, but most carbohydrate polymers are mostly low-loss for "normal" thicknesses. \$\endgroup\$ Feb 15, 2020 at 14:27
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    \$\begingroup\$ @MarcusMüller There aren't many carbohydrate polymers, and few used for enclosures. Examples would be cellulose, wood etc. Perhaps you're thinking of hydrocarbon polymers. \$\endgroup\$
    – Neil_UK
    Feb 15, 2020 at 16:51
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    \$\begingroup\$ @Neil_UK haha, you're right! Brain stuck between a coffee mug and a heap of DSP code. \$\endgroup\$ Feb 15, 2020 at 17:10
  • \$\begingroup\$ You can get ESP modules that havr U.FL jacks for an external antenna. \$\endgroup\$ Feb 15, 2020 at 22:49
  • \$\begingroup\$ @MarcusMüller I’m a bit confused. Does that mean as long as my enclosure wall is thin ABS, I shouldn’t worry? \$\endgroup\$ Feb 16, 2020 at 2:51

1 Answer 1


The inverted F antenna on many ESP modules is tuned for the band used by the module and can be de-tuned by other material in close proximity. space the antenna away from the material to avoid this effect. 10mm is probably enough.

  • \$\begingroup\$ So the gap between the enclosure wall and the antenna should be at least 10mm ? Can I ask what if the antenna has been slightly dented during shipping? Does it matter? \$\endgroup\$ Feb 16, 2020 at 2:55
  • \$\begingroup\$ Ok, I see in the photo the sheet metal antenna. that's going to work better than a printed antenna. but yeah, they're more fragile. all dents will hurt performance, small dents less than big dents. \$\endgroup\$ Feb 16, 2020 at 3:25

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