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yes, it's safe. It's not that different from regular WiFi or cellular signals. It's non ionizing (aka it doesn't have enough energy to instantly destroy cells unlike uv radiation) but it can heat up tissue, which is linked to cancer and worse (think microwave ovens).
There’s no risk of cancer from heating up tissue.
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I did some reading and it seems you are right. No Idea why phones come with a SAR rating then and why there are safe limits defined, when no one found unsafe limits.
Personally, I perceived it as a matter of good engineering: your phone shouldn't spend its energy to heat your ear.
Even from transmitting heat to the phone's components itself or other items that are nearby, e.g. laptops: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5219578/.
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There’s no risk of cancer from heating up tissue.
There is but it's sun burn type risks, not nuclear reactor type. A few unlucky people have been literally cooked to death by military radar. It's as awful as it sounds.
https://www.thenakedscientists.com/articles/questions/why-do...
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Interesting article. I wonder if any progress on the ITAR issue has been made since 2022? If Brad Parkinson can't steer ITAR in the direction of common sense, nobody can. (For those who don't know, he was the principal architect of the original Navstar GPS system.)
I would prefer we not have homemade cruise missiles all over the place. The people who need them can make them after all.
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> It's as awful as it sounds. Well to me it sounds like you'd get heat stroke and pass out before anything reaches particularly painful temperatures, because it's heating you pretty evenly and not via contact, but maybe that's not the right way to think about it? At higher frequencies I would guess it gets closer to normal burning?
This isn't really correct I'm afraid. The cause of SAR is predominantly dielectric losses and the loss tangent is a strong function of tissue type -- CSF, fat and bone are really quite different in terms of epsilon r and sigma, and one has to solve Maxwell with a human voxel model to work out SAR effectively which computationally is a pain. Once tissue heating has occurred what happens next is well described by the b…
This is great. It’s the last piece I needed for my suburban missile guidance system! This will be the last year the Joneses survive the annual block party. Can you do phased array radars next? I need the extra precision. There’s a few neighbors who don’t clean up after their dogs…
These should help. Tactical and Strategic Missile Guidance, Seventh Edition https://www.amazon.com/Tactical-Strategic-Missile-Guidance-S... Tactical missile warheads https://www.amazon.com/Tactical-Warheads-Progress-Astronauti...
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There’s no risk of cancer from heating up tissue.
I did some reading and it seems you are right. No Idea why phones come with a SAR rating then and why there are safe limits defined, when no one found unsafe limits.
I don't see why microwave heating wouldn't cause the same effect.
And that chip? Not even designed for this application - it is a PIR sensor chip repurposed.
The core of the radar is just a single multi-Ghz transistor (in the middle of the left half of the PCB), and a super clever feedback circuit made out of fancy shapes of copper traces that probably took someone years to design and perfect.
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In theory, though it sounds like to compete with LIDAR it will need about 1000x more antennas, with a related increase in electronics.
Any idea if these antennas can be made small/on a PCB, effectively miniaturizing them?