Specific Absorption Rate (SAR) Calculator
A Specific Absorption Rate (SAR) Calculator estimates the rate at which the human body absorbs energy from radiofrequency electromagnetic fields, typically during MRI scans or mobile phone usage. SAR is measured in watts per kilogram (W/kg) and is crucial for ensuring safety limits to prevent tissue heating and potential harm.
Specific Absorption Rate (SAR) Calculator
How to Use the SAR Calculator?
To use the Specific Absorption Rate (SAR) calculator effectively, you need to fill in the following fields with the appropriate values:
Conductivity of Various Human Tissues (Siemens/m): This value represents how easily electric current can flow through different types of human tissues. Common values for conductivity in human tissues are approximately:
- Brain: 0.33 S/m
- Muscle: 0.5 S/m
- Fat: 0.03 S/m
You should select the appropriate tissue type and input its conductivity value in Siemens per meter.
RMS of Electric Intensity of the Body (kg/m³): This field refers to the root mean square (RMS) value of the electric field intensity that the body is exposed to. The RMS value is a measure of the effective value of an alternating current or voltage. You will need to determine the electric intensity based on the specific exposure scenario or measurement.
Density of Human Tissue (kg/m³): This value indicates the mass per unit volume of the tissue type being analyzed. Typical density values for human tissues are:
- Brain: ~1040 kg/m³
- Muscle: ~1060 kg/m³
- Fat: ~920 kg/m³
Choose the relevant tissue type and enter its density in kilograms per cubic meter.
Once you have gathered the necessary values for these fields, input them into the SAR calculator on the provided website to compute the specific absorption rate for the selected human tissue under the specified electric field intensity.
What is SAR?
SAR stands for Specific Absorption Rate. It measures how much energy from a device is absorbed by a certain amount of body tissue. It is usually expressed in watts per kilogram (W/kg). Think of it like measuring how much heat a cup of coffee gives off when you hold it. The higher the SAR value, the more energy your body absorbs.
Why is SAR important?
SAR is important because it helps us know if using a device is safe for our health. If the SAR value is too high, it could mean that the device might be harmful. For example, if a phone has a high SAR, it might heat up your head more than a phone with a lower SAR when you talk on it for a long time.
What are the acceptable SAR Levels?
| Region | SAR Limit (W/kg) | Measurement Basis |
|---|---|---|
| European Economic Area | 2.0 | 10g tissue volume |
| USA and Canada | 1.6 | 1g tissue volume |
| Limb SAR | 4.0 | 10g tissue volume |
The Specific Absorption Rate (SAR) limits vary by region and are critical for ensuring safety standards in wireless devices.
In the European Economic Area, the SAR limit is set at 2.0 W/kg measured over a 10g tissue volume. In contrast, the USA and Canada have a lower limit of 1.6 W/kg, measured over a 1g tissue volume.
Additionally, for limb exposure, both regions maintain a limit of 4.0 W/kg, also based on a 10g tissue volume.