1. What is Specific Absorption Rate?

Specific Absorption Rate (SAR) measures the rate at which electromagnetic energy is absorbed by the human body when exposed to radio frequency electromagnetic fields. It's a key parameter in assessing safety limits for electromagnetic exposure.

2. How Does the Calculator Work?

The calculator uses the SAR formula:

Where:

• \( \sigma \) — Conductivity (S/m)
• \( E \) — Electric field strength (V/m)
• \( \rho \) — Mass density (kg/m³)
• \( SAR \) — Specific absorption rate (W/kg)

Explanation: The formula calculates the power absorbed per unit mass of tissue when exposed to an electromagnetic field.

3. Importance of SAR Calculation

Details: SAR calculation is crucial for evaluating electromagnetic safety, setting exposure limits, and ensuring compliance with regulatory standards for electronic devices and wireless technologies.

4. Using the Calculator

Tips: Enter conductivity in S/m, electric field in V/m, and mass density in kg/m³. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical SAR values for safety limits?
A: Most regulatory agencies set SAR limits around 1.6-2.0 W/kg averaged over 1 gram or 10 grams of tissue for general public exposure.

Q2: How is SAR measured in practice?
A: SAR is typically measured using specialized equipment that scans electromagnetic fields in phantom models that simulate human tissue properties.

Q3: What factors affect SAR values?
A: SAR depends on frequency, field strength, tissue properties, exposure duration, and the distance from the radiation source.

Q4: Are there different SAR limits for different body parts?
A: Yes, SAR limits vary for whole-body exposure, localized exposure (head/torso), and extremities (limbs), with higher limits allowed for extremities.

Q5: How does SAR relate to thermal effects?
A: SAR primarily measures the thermal effects of electromagnetic exposure, as absorbed energy is converted to heat in biological tissues.