The FCC Workshop ended last May, and BTL immediately posted about the changes to KDB447498 D04 Interim General RF Exposure Guidance v01<FCC KDB 447498 DR04 has been released>. In 2022, the FCC also officially notified that the new version of the requirements will be implemented on April 1, 2022.
I did a simple comparison of FCC v.s. IC with you, FCC also conducted online training in 3/2. This time we will explain three methods of Exemption Thresholds.
Option A: when the output power P < 1 mW
Any product, all frequencies and all distances, are exempt from SAR testing and MPE testing under this condition.
When a product has simultaneous transmissions, the following conditions must be met before it can be exempted:
1. All sources ΣP < 1 mW or P< 1 mW
2. And the antenna spacing > 2 cm
Option B: Frequency range 300 MHz - 6 GHz, 5 mm ≤ distance ≤ 40 cm
Maximum time average power or effective radiated power (ERP), whichever is greater, ≤ Pth (very important, in the past, FCC only looked at direct power, now it is direct power and radiated power, and the two larger ones are selected for exemption test determination)
The complete Pth is calculated as follows:
mW : dBm：
Distance(mm) | ||||||||
Freq(MHz) | 5 | 10 | 15 | 20 | ||||
FCC | FCC | FCC | FCC | FCC | FCC | FCC | FCC | |
mW | dBm | mW | dBm | mW | dBm | mW | dBm | |
300 | 39 | 15.91 | 65 | 18.13 | 88 | 19.44 | 110 | 20.41 |
450 | 22 | 13.42 | 44 | 16.43 | 67 | 18.26 | 89 | 19.49 |
835 | 9 | 9.54 | 25 | 13.98 | 44 | 16.43 | 66 | 18.20 |
1900 | 3 | 4.77 | 12 | 10.79 | 26 | 14.15 | 44 | 16.43 |
2450 | 3 | 4.77 | 10 | 10.00 | 22 | 13.42 | 38 | 15.80 |
3600 | 2 | 3.01 | 8 | 9.03 | 18 | 12.55 | 32 | 15.05 |
5800 | 1 | 0.00 | 6 | 7.78 | 14 | 11.46 | 25 | 13.98 |
Freq(MHz) | 25 | 30 | 35 | 40 | ||||
FCC | FCC | FCC | FCC | FCC | FCC | FCC | FCC | |
mW | dBm | mW | dBm | mW | dBm | mW | dBm | |
300 | 129 | 21.11 | 148 | 21.70 | 166 | 22.20 | 184 | 22.65 |
450 | 112 | 20.49 | 135 | 21.30 | 158 | 21.99 | 180 | 22.55 |
835 | 90 | 19.54 | 116 | 20.64 | 145 | 21.61 | 175 | 22.43 |
1900 | 66 | 18.20 | 92 | 19.64 | 122 | 20.86 | 157 | 21.96 |
2450 | 59 | 17.71 | 83 | 19.19 | 111 | 20.45 | 143 | 21.55 |
3600 | 49 | 16.90 | 71 | 18.51 | 96 | 19.82 | 125 | 20.97 |
5800 | 40 | 16.02 | 58 | 17.63 | 80 | 19.03 | 106 | 20.25 |
Pth is for head / body exposure can be scaled by x 2.5 when addressing extremity exposure.
Option C: MPE above 300 kHz
R > λ/ 2 π，R is the distance between the antenna and the human body, and considering SAR and MPE exemptions, R needs to be less than 20cm.
And the calculation method of wavelength:
v = fλ：v= speed of light = 3 x 108 m/s；f= frequency (Hz)
For the wavelengths of the frequencies in the table, the calculation results are as follows, which can be quickly brought in for confirmation.
When the MPE cannot be exempted, the MPE test or calculation is required, and the restrictions are as follows:
The impact of this update will be that the low-power products of BT and SRD will have a greater impact. For example, the product will enter the North American customs before 4/1/2022. It is recommended that you prepare in advance, and BTL will assist you in evaluating, such as regulations, related If you have any questions about testing or certification, please contact us and our professional team will answer you for any related questions arisen.
