RF Exposure RulesSAR and MPE Estimation SummaryBased on current interpretations of US radio law by FCCBased upon the TCB Exclusion List and various interpretations by FCCBased upon experience of ATCB

RF Exposure: SAR or MPE ?Questions to ask:Is device used at less than 20cm to the body? And is the device above the Low Threshold conditions in the TCB exclusion list of July 17, 2002?Is the device listed in 2.1093(c)?

If the answer to either of the above is YES than SAR evaluation is required

Definitions and NomenclatureHost-independent: certification for device to be installed and expected to comply in any applicable host unfeasible for portable exposure conditionsModule: Transmitter operating (usually) internally as part of another device or productFull Modular Approval: Part 15 Tx module that meets eight criteria of DA 00-1407, e.g., EMC tested stand-alone (stand-alone SAR is undefined), FCC ID label on host, etc. A full Modular approval with unlimited SAR configurations is not allowed.

Definitions and NomenclatureLimited Modular Approval (LMA): LMA is used with SAR testing on an Unlicensed module to allow SAR tests to be applied to more than one model. Licensed module: Certification for Licensed Tx daughter-board or Tx box, installed in RF category Mobile or Fixed conditions only. Antenna might be specified with limit on gain.Dedicated host: Tx intended for OEM integration or permanent installation into a specific host product; also covered by 3-host method for integral-antenna plug-in cards. Applies specifically to Part 15 modules above 100mW

Portable DevicesOperate less then 20cm from any user or bystanderUsually involves body worn or ear or face held devicesSAR Testing required if above the low threshold limit in July 17, 2002 TCB Exclusion ListSome devices are specifically required by law to have SAR testing as a condition of Certification, regardless of RF Pout.Example: Cellphones; 802.11a PCMCIA card

Safety Rule References on Human ExposureANSI C95.1IEEE 1528OET 65OET 65-C FCC Part 1.1037FCC Part 2.1091Mobile DevicesFCC Part 2.1093Portable DevicesFCC Part 15.247(b)(4)FCC Part 15E

Part 15 and RF ExposureThe FCC will require a MPE study (RF estimation) for both Mobile and Fixed devices. (i.e.15.247 and UNII devices).

Estimation should be performed with highest gain antenna of each antenna type.

For SAR and MPE evaluation, the default limits are the Uncontrolled Environment. It is assumed that users of Part 15 devices have no understanding of radio principals.

You cannot evaluate any Part 15 device to the Controlled/Occupational limits.

Part 15 and RF Exposure

The vast majority of Low Power Part 15 Intentional Radiators are categorically excluded from Routine Evaluation under the FCC rules. However, the FCC will require a SAR test for RF category Portable devices if the power exceeds 60/f(GHz) if contact with antenna is allowed, or 120mW/f(GHz) if 2.5cm is maintained to the antenna.

Example: 15.231 key fob Tx do not need SAR test

Supplement C: MPE Exposure Limits

(A) Limits for Occupational/Controlled Exposure

FrequencyElectric FieldMagnetic FieldPower Density Averaging Time

RangeStrength (E)Strength (H)(S)|E|2, |H|2 or S

(MHz)(V/m)(A/m)(mW/cm2)(minutes)

0.3-3.06141.63(100)*6

3.0-301842/f4.89/f(900/f2)*6

30-30061.40.1631.06

300-1500----f/3006

1500-100,000----56

(B) Limits for General Population/Uncontrolled Exposure

FrequencyElectric FieldMagnetic FieldPower Density Averaging Time

RangeStrength (E)Strength (H)(S)|E|2, |H|2 or S

(MHz)(V/m)(A/m)(mW/cm2)(minutes)

0.3-1.346141.63(100)*30

1.34-30824/f2.19/f(180/f2)*30

30-30027.50.0730.230

300-1500----f/150030

1500-100,000----1.030

f = frequency in MHz*Plane-wave equivalent power density

NOTE 1: See Section 1 for discussion of exposure categories.

NOTE 2: The averaging time for General Population/Uncontrolled exposure to fixed transmitters is not applicable for mobile and portable transmitters. See 47 CFR 2.1091 and 2.1093 on source-based time-averaging requirements for mobile and portable transmitters.

Supplement C: SAR Limits

(A) Limits for Occupational/Controlled Exposure (W/kg)

PRIVATE Whole-Body

Partial-Body

Hands, Wrists, Feet and Ankles

0.4

8.0

20.0

(B) Limits for General Population/Uncontrolled Exposure (W/kg)

PRIVATE Whole-Body

Partial-Body

Hands, Wrists, Feet and Ankles

0.08

1.6

4.0

NOTE 1: See Section 1 for discussion of exposure categories.

NOTE 2: Whole-Body SAR is averaged over the entire body, partial-body SAR is averaged over any 1 gram of tissue defined as a tissue volume in the shape of a cube. SAR for hands, wrists, feet and ankles is averaged over any 10 grams of tissue defined as a tissue volume in the shape of a cube.

NOTE 3: At frequencies above 6.0 GHz, SAR limits are not applicable and MPE limits for power density should be applied at 5 cm or more from the transmitting device.

NOTE 4: The time averaging criteria for field strength and power density do not apply to general population SAR limit of 47 CFR 2.1093.

MPE Estimation FormulaTo Determine Power Density (s):S=P x G /4piR2

FCC requires that RF category Mobile devices calculate power density for 20cm.Calculation of power density at other distances for Mobile products not allowed.Calculation of power density for Fixed devices is allowed, as long as distance not shown less than 20cm

Full Modular Approvals (Part 15)By Definition, these transmitters must have own reference oscillator. In addition a separate letter on Applicant letterhead addressing all these items must accompany the filing:RF shielding.Buffered data input/output ports Power supply regulationPermanent antenna or unique connectorTested in stand alone conditionLabeled with own ID numberInstructions to operator / OEM integratorMust meet RF Exposure requirements.

Limited Modular Approval (LMA) Part 15If any of the 8 elements on the preceding slide cannot be met, a limited modular approval may be obtained in some circumstances. LMAs define special circumstances where Certification is validExample 1: Wireless mini-PCI 802.11b/g card without voltage regulationExample 2: Wireless mini-PCI 802.11b/g card with SAR results which may apply to a specific chassis or model notebook PC host.

Licensed ModulesThere is officially no such thing as a Licensed Modular TransmitterThe Rules of DA 00-1407 do not apply DO NOT ATTEMPT

Complex ExampleNotebook PC with built-in Bluetooth, WiFi, and GPRSAre Part 15 transmitters separately Certified?Are Part 15 transmitters Modular Approved?Are any transmitters capable of co-location?Is BT below 5mw?Are any transmitters end-user installable?Labeling?

SAR Testing Updates.SAR Probes must be calibrated on a yearly basis. The only allowed exception is when the probe manufacturer specifically permits different calibration intervals.Tolerance between RF conducted power measured at the EMC lab and SAR lab must be within 5%. Common spectrum analyzers are good to only 1dB (~25%)TCBs now allowed to do SAR approval work from 300MHz to 6GHz.

Additional DocumentsFCC has released specific guidance for SAR testing of WiFi products.FCC is now specifying specific combinations of channel, power, and data rates.FCC has released SAR review to TCBs to frequencies of 6GHz.

Contact InformationWilliam H. GraffPresident and Director of EngineeringAmericanTCB, Inc.6731 Whittier Ave.McLean, VA 22101

mailto: whgraff@ATCB.com

Corporate Phone: (703)847-4700Corporate FAX: (703)847-6888Direct Mobile: +886 920399260

SKYPE: whgraff