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SAR (Specific Absorption Rate) Definition


SAR is how much and how fast energy enters the body from an EM device.

Phone Waves are Radio Waves

Your body absorbs some of your cell phone’s radio waves.

Radio waves are electromagnetic energy waves in the “radio frequency” (RF) range.

The RF range is between 100 kHz and 10 GHz.

Cell phone radiation tests don't include holding the phone on your ear.
Cell phone radiation tests don’t include holding the phone on your ear.

When your phone is near or on your ear, it sends radio waves to your ear, head, and brain.

When your phone is in your pocket, it sends radio waves to your hips and groin.

The phone antenna is the hottest RF spot on the phone.

It emits the energy contact the cell tower.

Radio Waves are Non-Ionizing Radiation

X-ray and gamma rays are “ionizing radiation”

Ionization strips an electron from a molecule.

If that molecule is part of your DNA, you can get cancer.

Radio waves are non-ionizing radiation.

They do not knock out DNA electrons.

However, they do create oxidative stress.

Oxidative stress creates free radicals.

Free radicals give you cancer.

The Government Limits Cell Phone Radiation

The US government requires phone companies limit the RF waves coming from their mobile phones.

In the US, the FCC sets this phone radiation limit.

The limit is SAR, or specific absorption rate.

SAR is a measurement of how much non-ionizing RF radiation the body absorbs.

Phone companies use independent laboratories to measure the RF coming from their phones.

The laboratories test the phones using fluids that mimic the absorption properties of the human head.

For any 1 gram of human tissue, the SAR has to be at or below 1.6 watts / 1,000.

The maximum phone SAR rating is 1.6 watts per kilogram (W/kg) measured over the gram of tissue that is absorbing the most energy.

The pass the test, that wattage must be 0.0016 watts or fewer.

They could have just said that the maximum SAR maximum is “0.0016 watts per gram,” but they didn’t. They gave a maximum in thousands grams, and a measurement in grams.

They also helped write the tax code. /s

High SAR Might Be Safer Than Low SAR

It would be reasonable at this point to look for the phone with the lowest SAR.

Reasonable, but not helpful.

The phone’s SAR value is part of a larger radiation picture.

When laboratories test phone SAR, they don’t put the phone on the test dummy’s head.

The phone is a few millimeters away.

Since radiation drops off with distance, the SAR drops to a low value.

Independent researchers have put the phones on the dummy.

They’ve gotten SAR’s of 500% greater than the “official” phone values.

Your RF absorption is also going to change when you move the phone.

Any change that also changes the phone antenna’s distance from your flesh will change the SAR value.

When your phone has a bad connection to the cell tower, it increases its power. You absorb some of that energy.
When your phone has a bad connection to the cell tower, it increases its power. You absorb some of that energy.

A weak cell connection will change the SAR.

When the phone has a weak connection, it increases its power output.

The phone puts out more power to reach the cell tower.

That power increase also increases the radio waves you absorb.

The actual energy you absorb includes: “[o]utput power, antenna gain, duty cycle, and separation from the body…”

All of this makes the SAR just about meaningless.

Give your head distance from the phone.
Give your head distance from the phone.


  1. Specific Absorption Rate, Wikipedia
  2. Specific Aborption Rates for Cell Phones, Federal Communications Commission (FCC)
  3. FCC ID Search, Federal Communications Commission (FCC)
  4. Specific Absorption Rate (SAR) For Cell Phones: What It Means For You, Federal Communications Commission (FCC)
  5. Wireless Devices and Health Concerns, FCC
  6. Cell Phones, US Food and Drug Administration (FDA)
  7. Radio Frequency, Wikipedia
  8. Bioelectromagnetics, Wikipedia
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