RF Exposure and Modular Equipment Considerations

1. RF Exposure and Modular Equipment Considerations

2. 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

3. 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

4. Definitions and Nomenclature • Host-independent: certification for device to be installed and expected to comply in any applicable host – unfeasible for portable exposure conditions • Module: Transmitter operating (usually) internally as part of another device or product • 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.

5. Definitions and Nomenclature • 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. • 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

6. Portable Devices • Operate less then 20cm from any user or bystander • Usually involves body worn or ear or face held devices • SAR Testing required if above the low threshold limit in July 17, 2002 TCB Exclusion List • Some 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

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

8. Part 15 and RF Exposure • The 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.

9. 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

10. Supplement C: MPE Exposure Limits

11. Supplement C: SAR Limits

12. MPE Estimation Formula • To 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

13. 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 regulation • Permanent antenna or unique connector • Tested in “stand alone” condition • Labeled with own ID number • Instructions to operator / OEM integrator • Must meet RF Exposure requirements.

14. 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.

15. 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

16. Complex Example • Notebook PC with built-in Bluetooth, WiFi, and GPRS • Are 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?

17. 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.

18. 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.

19. Contact Information • William 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