In general, devices with plastic cases typically have better reception because plastic is RF transparent. Devices with metal cases tend to have worse because they block RF. That’s grossly simplified but it’ll get you started on researching it.
Not a great example of the improved reception of metal frame phones, because it was the iPhone 4 that lost reception quality significantly when it was held on the metal sides and your finger/hand happened to be near the lower left corner. This was a perfectly natural way to hold the phone and most impacted left-handers.
Apple famously responded by saying “you just need to not hold it like that”, rather than admitting an engineering mistake.
In general, devices with plastic cases typically have better reception because plastic is RF transparent. Devices with metal cases tend to have worse because they block RF. That’s grossly simplified but it’ll get you started on researching it.
Since the iPhone 4? lots of phones simply moved the antennas to the exterior, so that’s not really a problem nowadays.
Not a great example of the improved reception of metal frame phones, because it was the iPhone 4 that lost reception quality significantly when it was held on the metal sides and your finger/hand happened to be near the lower left corner. This was a perfectly natural way to hold the phone and most impacted left-handers.
Apple famously responded by saying “you just need to not hold it like that”, rather than admitting an engineering mistake.
https://www.cnet.com/tech/mobile/iphone-4-signal-problems-apple-says-dont-hold-it-like-that/