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RF Exposure and Modular

Equipment Considerations

RF Exposure RulesSAR and MPE Estimation Summary

Based on current interpretations of US radio law by FCC

Based upon the TCB Exclusion List and various interpretations by FCC

Based upon experience of ATCB

RF Exposure: SAR or MPE ?

Questions to ask:o 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?

o 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 Nomenclatureo Host-independent: certification for device to be

installed and expected to comply in any applicable host – unfeasible for portable exposure conditions

o Module: Transmitter operating (usually) internally as part of another device or product

o Full 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 Nomenclatureo Limited 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.

o 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.

o 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 Deviceso Operate less then 20cm from any user or bystandero Usually involves body worn or ear or face held

deviceso SAR Testing required if above the low threshold limit

in July 17, 2002 TCB Exclusion Listo Some devices are specifically required by law to

have SAR testing as a condition of Certification, regardless of RF Pout.

o Example: Cellphones; 802.11a PCMCIA card

Safety Rule References on Human Exposure

o ANSI C95.1o IEEE 1528o OET 65o OET 65-C o FCC Part 1.1037o FCC Part 2.1091 Mobile Deviceso FCC Part 2.1093 Portable Deviceso FCC Part 15.247(b)(4)o 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 LimitsSupplement C: MPE Exposure Limits(A) Limits for Occupational/Controlled Exposure

Frequency Electric Field Magnetic Field Power Density Averaging TimeRange Strength (E) Strength (H) (S) |E|2, |H|2 or S(MHz) (V/m) (A/m) (mW/cm2) (minutes)

0.3-3.0 614 1.63 (100)* 63.0-30 1842/f 4.89/f (900/f2)* 630-300 61.4 0.163 1.0 6

300-1500 -- -- f/300 61500-100,000 -- -- 5 6

(B) Limits for General Population/Uncontrolled Exposure

Frequency Electric Field Magnetic Field Power Density Averaging TimeRange Strength (E) Strength (H) (S) |E|2, |H|2 or S(MHz) (V/m) (A/m) (mW/cm2) (minutes)

0.3-1.34 614 1.63 (100)* 301.34-30 824/f 2.19/f (180/f2)* 3030-300 27.5 0.073 0.2 30

300-1500 -- -- f/1500 301500-100,000 -- -- 1.0 30

f = frequency in MHz *Plane-wave equivalent power densityNOTE 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 andportable transmitters.

Supplement C: SAR LimitsSupplement C: SAR Limits (A) Limits for Occupational/Controlled Exposure (W/kg)

Whole-Body Partial-Body Hands, Wrists, Feet and Ankles

0.4 8.0 20.0

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

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 oftissue defined as a tissue volume in the shape of a cube. SAR for hands, wrists, feet and ankles isaveraged 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 shouldbe 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 populationSAR limit of 47 CFR §2.1093.

MPE Estimation Formula

To Determine Power Density (s):o S=P x G /4piR2

o FCC requires that RF category “Mobile” devices calculate power density for 20cm.

o Calculation of power density at other distances for “Mobile” products not allowed.

o 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:

1. RF shielding.2. Buffered data input/output ports 3. Power supply regulation4. Permanent antenna or unique connector5. Tested in “stand alone” condition6. Labeled with own ID number7. Instructions to operator / OEM integrator8. Must meet RF Exposure requirements.

Limited Modular Approval (LMA) Part 15

If 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 valid

Example 1: Wireless mini-PCI 802.11b/g card without voltage regulation

Example 2: Wireless mini-PCI 802.11b/g card with SAR results which may apply to a specific chassis or model notebook PC host.

Licensed Modules

There is officially no such thing as a “Licensed Modular Transmitter”

The Rules of DA 00-1407 do not apply – DO NOT ATTEMPT

Complex Example

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

SAR Testing Updates.

o SAR Probes must be calibrated on a yearly basis. The only allowed exception is when the probe manufacturer specifically permits different calibration intervals.

o 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%)

o TCBs now allowed to do SAR approval work from 300MHz to 6GHz.

Additional Documents

FCC 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. Graff

President and Director of Engineering

AmericanTCB, Inc.

6731 Whittier Ave.

McLean, VA 22101

mailto: whgraff@ATCB.com

Corporate Phone: (703)847-4700

Corporate FAX: (703)847-6888

Direct Mobile: +886 920399260

SKYPE: whgraff