FCC SAR Testing & Radio Frequency Exposure 2 — Questions and Answers
Question 1: What is the time-averaging period used for MPE calculations in uncontrolled (general population) environments per FCC rules?
- 6 minutes
- 15 minutes
- 30 minutes (Correct answer)
- 60 minutes
Correct answer: 30 minutes
The FCC specifies a 30-minute time-averaging period for MPE calculations in uncontrolled/general population environments, compared to 6 minutes for controlled/occupational environments.
Question 2: What instrument is used to measure the electric field distribution within a SAR phantom during testing?
- Network analyzer with directional coupler
- Isotropic electric field (E-field) probe (Correct answer)
- Calibrated spectrum analyzer
- Calibrated power meter with horn antenna
Correct answer: Isotropic electric field (E-field) probe
An isotropic E-field probe is inserted into the phantom and scanned robotically to map the three-dimensional electric field distribution from which the peak SAR is calculated.
Question 3: At what power level must a device under test be operated during FCC SAR compliance testing?
- 50% of rated power
- Average operational power
- Maximum certified transmission power (Correct answer)
- Minimum detectable power
Correct answer: Maximum certified transmission power
SAR testing must be conducted at the maximum certified transmission power level to ensure the worst-case RF exposure is evaluated for compliance.
Question 4: Which international standard, published by the IEC, is frequently harmonized with FCC SAR test requirements for portable wireless devices?
- IEC 61000-4-3
- IEC 60601-1
- IEC 62209 (Correct answer)
- IEC 61326-1
Correct answer: IEC 62209
IEC 62209 (Human exposure to radio frequency fields from hand-held and body-mounted wireless communication devices) is harmonized with FCC SAR requirements and recognized by accreditation bodies worldwide.
Question 5: Which FCC rule section governs SAR evaluation requirements for portable transmitting devices?
- 47 CFR Part 15.31
- 47 CFR Part 1.1310
- 47 CFR Part 2.1093 (Correct answer)
- 47 CFR Part 24.52
Correct answer: 47 CFR Part 2.1093
47 CFR Part 2.1093 establishes RF radiation exposure evaluation requirements specifically for portable devices, including the 1.6 W/kg SAR limit averaged over 1 gram.
Question 6: What scanning grid spacing is typically used during the coarse scan phase of SAR measurement per IEEE 1528?
- 1 mm
- 5 mm
- 10–15 mm (Correct answer)
- 25 mm
Correct answer: 10–15 mm
IEEE 1528 specifies a coarse scan grid spacing of approximately 10–15 mm to quickly map the overall SAR distribution, followed by a fine scan at approximately 5 mm spacing around the peak region.
Question 7: What is the time-averaging period for MPE calculations in occupational/controlled environments per FCC rules?
- 6 minutes (Correct answer)
- 15 minutes
- 30 minutes
- 60 minutes
Correct answer: 6 minutes
The FCC specifies a 6-minute time-averaging period for occupational/controlled environments, reflecting the assumption that trained workers can monitor and manage their RF exposure.
FCC SAR Testing & Radio Frequency Exposure 2
What is the time-averaging period used for MPE calculations in uncontrolled (general population) environments per FCC rules?