⚠️ RF Safety & Exposure Estimator

⚡ What is Power Density?

Power density is the amount of electromagnetic energy flowing through a given area, measured in watts per square meter (W/m²) or milliwatts per square centimeter (mW/cm²).

$S = \frac{P \cdot G}{4\pi r^2}$

Where:

• $S$: Power density (W/m²)
• $P$: Transmitter power (watts)
• $G$: Antenna gain (linear, not dB)
• $r$: Distance from antenna (meters)

🧬 What is SAR (Specific Absorption Rate)?

SAR measures how much RF energy is absorbed by human tissue, expressed in watts per kilogram (W/kg). It's a critical safety metric for devices close to the body.

$\text{SAR} = \frac{\sigma |E|^2}{\rho}$

Where:

• $\sigma$: Tissue conductivity (S/m)
• $E$: Electric field strength (V/m)
• $\rho$: Tissue density (kg/m³)

Regulatory Limits:

• FCC/ISED (USA/Canada): 1.6 W/kg (1-gram average)
• ICNIRP (Europe/International): 2.0 W/kg (10-gram average)

🛡️ Safety Standards

Two main exposure categories exist:

• Occupational/Controlled: Trained personnel aware of exposure (higher limits)
• General Public/Uncontrolled: General population (stricter limits)

Common Frequency Ranges:

• 30-300 MHz: FM radio, VHF communications
• 300-3000 MHz: Cell phones, Wi-Fi (lower bands), microwave ovens
• 3-30 GHz: Satellite, radar, 5G mmWave

🎯 How to Use This Tool

1. Enter your transmitter power (supports W, mW, kW)
2. Set antenna gain (in dBi) - defaults to 0 dBi (isotropic)
3. Enter operating frequency (supports Hz, kHz, MHz, GHz)
4. Choose exposure category (Occupational or General Public)
5. The tool calculates:
   • Power density at various distances
   • Estimated SAR values
   • Safe distance boundaries
   • Compliance status with regulatory limits

Safety Zone Map: The visualization shows color-coded zones indicating safety levels at different distances from the antenna.