During the presentation of "3.2 Interim Simplified RFX Guidance for Portable Devices" at this meeting, many manufacturers and laboratories were startled to learn that the Body SAR testing distance would be reduced to 5mm, a stricter requirement. After analysis by BTL, here are the clarifications:
The document is an interim guide, not a standard requirement, and it specifies upfront that it reflects the author's views, not the collective views of the FCC.
The stricter Body SAR guidelines may represent future trends. For instance, CE authorities have recently discussed reducing Body SAR testing distance to 0mm, although official consolidation of opinions is still underway.
Regarding FCC changes, the most affected products are mobile phones. The mentioned Table/Laptop products have clearly defined requirements as per KDB616217 D04 and KDB941225 D07:
Tablet:
DUT size <20cm: Testing distance is 5mm, separation the Phantom.
DUT size >20cm: Testing distance is 0mm, contacting the Phantom.
Laptop:
Keyboard bottom must test the 0mm contact with the Phantom. If the bottom has pads taller than 5mm, the pads should either be removed or discussed with KDB and officials.
Consequently, testing distances stated in the document are necessarily within 5mm as per regulatory requirements.
For MiFi products, primarily tested in Hotspot Mode, the requirements per KDB941225 D06 are:
Dimensions >9x5cm: Testing distance is 10mm.
Dimensions <9x5cm: Testing distance is 5mm.
Until KDB941225 D06 is updated, tests will adhere to existing rules.
Mobile phones are primarily impacted by previous KDB447498 D01 v06 rules stating Body-Worn devices must be tested at distances no greater than 25mm. Devices designed for operation on straps/cords worn on the body or devices not requiring additional accessories for body-worn use must be tested under all usage conditions at distances no greater than 5mm.
KDB447498 D04 v01 retains only the stricter requirement of a 5mm testing distance for devices with the above descriptions.
Both KDB447498 D01 v06 and KDB447498 D04 v01 remain valid under current FCC regulations, and certifications can choose either for testing.
Mobile phones tested at 15mm correspond to KDB447498 D01 v06.
Mobile phones tested at 5mm correspond to KDB447498 D04 v01.
However, this workshop document also mentions:
Body SAR, in non-"hotspot" operating mode: For all §2.1093-portable devices, conduct a 1-g SAR test at a distance of 5 mm unless there is at least one available "close-contact" holder.
For identified “on-body” holders, the following applies:
The minimum test separation distance can be increased as supported by the holder structure, but not to exceed 25 mm (consistent with present guidance since KDB 47498v06).
Filed grant exhibits must identify and show the holder device as tested and provide a descriptive statement in the grant comments.
The user documentation (manuals, or similar) must provide a statement that FCC compliance testing was done with that holder and provide the separation distance for
which compliance was demonstrated.
If Body SAR is tested at a 5-mm distance using KDB 447498 D04 v01, the conditions mentioned above must be met, and the shipping grant products must have corresponding close-contact holders.
For further clarification or if there are additional questions, you can contact BTL for more detailed professional support.
