1. What is SAR?

The Specific Absorption Rate (SAR) is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field. It's expressed in watts per kilogram (W/kg).

2. How Does the Calculator Work?

The calculator uses the SAR equation:

Where:

• \( Power \) — Transmitter power output in Watts
• \( Duty\ Cycle \) — Fraction of time transmitter is active (0 to 1)
• \( Distance \) — Distance from transmitter in meters
• \( Area \) — Exposure area in square meters

Explanation: The equation calculates the RF energy absorption per unit mass of tissue, accounting for transmitter power, duty cycle, distance, and exposure area.

3. Importance of SAR Calculation

Details: SAR calculations are crucial for assessing compliance with safety limits for RF exposure, designing safe wireless devices, and evaluating environmental RF exposure levels.

4. Using the Calculator

Tips: Enter power in Watts, duty cycle as a fraction (0-1), distance in meters, and area in square meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are safe SAR limits?
A: For general public exposure, the FCC limit is 1.6 W/kg averaged over 1g of tissue. ICNIRP recommends 2 W/kg averaged over 10g of tissue.

Q2: How does distance affect SAR?
A: SAR decreases with the square of distance from the source - doubling distance reduces SAR to 1/4 of original value.

Q3: What's a typical duty cycle for mobile phones?
A: For GSM phones, duty cycle is typically 1/8 (0.125) during calls. For other technologies, it varies based on transmission mode.

Q4: Are there limitations to this calculation?
A: This simplified model assumes far-field conditions and uniform exposure. Actual SAR depends on frequency, tissue properties, and exposure geometry.

Q5: How is SAR measured in practice?
A: SAR is typically measured using specialized equipment and standardized procedures with tissue-simulating liquids and probe scanners.