Body SAR and FCC...GSM, GPRS, EDGE KDB 941225 D03 GSM, E-GPRS, EDGE Dual Transfer Mode (DTM) KDB 941225 D04 LTE KDB 941225 D05 FCC Specific Guidance - Platform 13 Device Type KDB Exposure

Body SAR and FCC

Mark Briggs UL Verification Services TCB

Overview

• FCC ≠ IEC 62209-2• Specific guidance

• Technology specific- Brief mention

• Hot spot capabilities in smaller devices (handsets / hotspot modems)• Smaller hand-held devices• “Phablets”• Laptops and tablets

• SAR for modules

• General approval requirements

• Modules for use in laptops and tablets

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FCC Does Not Follow EN/IEC 62209-2

• FCC requirements pre-dated IEC 62209-2 and were developed toaddress rf exposure issues of body-worn transmitters

• Even when IEC 62209-2 was released FCC had concerns(reference RF Exposure training, April 2010 TCBC Workshop)

• Provides body SAR test position for some product configurations

• Concerns about tissue dielectric parameter conservativeness

• Simultaneous transmission & modular configurations insufficient

• Fast SAR, test reduction and other considerations - lack detail proceduresto implement reliable test protocol

• FCC publications with primary guidance for rf exposure and SAR:

• KDB 447498 – General rf procedures, including thresholds for exemptingSAR measurements

• KDB 865664 – SAR measurement procedures and reporting guidance

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IEC 62209-2 / EU vs FCC KDB 865664 D01

FCC general test procedures are in KDB 865664 D01 • Additional “KDBs” provide technology-specific test reduction

guidance and platform/device specific test guidance

Primary differences from IEC 62209-2

• Tissue fluid• IEC 62209 uses the head liquids described in IEEE 1528 / IEC 62209-1• FCC has body-specific liquids

• They believe these liquids are more representative of the body and based on thepermittivity and conductivity of muscle

• Limits

• Simultaneous transmissions

• Detailed test guidance for certain device form factors

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FCC Body Tissue Fluid • As described previously, FCC requires different dielectric

parameters for the Tissue simulating liquid (TSL).

KDB 865664 D01 SAR Measurement 100MHz to 6GHz v01r02 Appendix A

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FCC Limits

• EU limits are 2W/Kg averaged over 10g• FCC limits are 1.6W/Kg averaged over 1g• These are not likely going to be changed …

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FCC General Guidance – KDB 447498 SAR Exclusion KDB 447498 • SAR exclusion thresholds

• May exclude a SAR evaluation based on power level, operating frequency,distance from person to device*, tissue type (head/body or extremity)• KDB 447498 4.3.1• e.g. Bluetooth excluded from body SAR measurement if < 9.5mW

If that transmitter operates simultaneously with another transmitter then the SAR value for the excluded transmitter is estimated • KDB 447498 4.3.2• Estimated SAR for 9.4mW Bluetooth at ≤ 5mm separation = 0.378 W/Kg

• Thresholds and estimated values use power rounded to closest mW• If Bluetooth power >= 9.5mW ( > 9.7dBm) then SAR is required!

* Although transmit antenna-to-device is indicated in the KDB, further reading explainsthat for small devices and devices used close to the body you need to use device-to-person separation distance.

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KDB 447498 Threshold for ≤ 5mm Separation

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1

10

100

1000

0 1000 2000 3000 4000 5000 6000

Thre

shol

d Po

wer

(mW

)

Frequency (MHz)

FCC General Guidance – Simultaneously Operating Transmitters KDB 447498 and Simultaneous Transmissions (multiple transmitters) • Multiple transmitters operating at the same time

• Difficult to measure SAR since TSL are different for different transmitteroperating frequencies

• FCC offers three approaches to determine compliance

1. Sum individual SAR values and compare to limit, if less than limit(1.6W/Kg for body SAR) then device complies

2. Determine ratio between the SAR values and distance between the peakSAR locations (SAR to Peak Location Separation Ratio = SPLSR

(SAR1 + SAR2)1.5 /R ≤ 0.04 then device complies

3. If (1) or (2) don’t work, last alternative is the volume scanRequires larger, high resolution scan for each transmitter. Scans are overlaid and summed. Lots of time required to make this scan.

• IEC 62209 offers options 1 and 3 but only required if SAR hot spots overlap.9

FCC General Guidance - SPLSR (SAR1 + SAR2)1.5 /R ≤ 0.04

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Sum SAR (W/Kg) Minimum Separation 3.2 143 mm 2.8 117 mm 2.4 93 mm 2 71 mm

1.6 51 mm 1.4 41 mm 1.2 33 mm 1.0 25 mm 0.8 18 mm

Note – previously FCC may have inferred that provided antennas were more than 5cm apart simultaneous SAR need not be considered. From the table above the minimum is 14cm to cover SAR1 = SAR2 = 1.6 W/Kg

FCC Specific Guidance

• Technology specific

• Concentrate on test reduction to help limit the amount of testing performedfor common technologies• Guidance for 802.11, LTE, 3G HSPA, HSPA+• Used for body and head (and extremity) SAR testing• Limit the channels/operating modes tested based on output power

• Device specific

• Concentrate on test methods to define required tests for specific devices orspecific functions

• Some only apply to body-SAR, other to head and body SAR measurements

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FCC Specific Guidance - Technology

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Technology KDB

802.11abg Currently under review to add 802.11ac

KDB 248227 D01

WiMax KDB 615223 D01

3G KDB 941225 D01

HSPA and 1x Advanced KDB 941225 D02

GSM, GPRS, EDGE KDB 941225 D03

GSM, E-GPRS, EDGE Dual Transfer Mode (DTM) KDB 941225 D04

LTE KDB 941225 D05

FCC Specific Guidance - Platform

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Device Type KDB Exposure Condition

Dongle Transmitters KDB 447498 D02 Body (5mm)

Portable Hot Spots KDB 941225 D06 Body (10mm or 5mm)

Tablets and Laptops KDB 616217 D04 Body (0mm separation)

Press-to-Talk Radios KDB 643646 D01 Head

UMPC KDB 941225 D07 UMPC Mini Tablet Body (5mm separation)

Handsets KDB 648474 D04 Body & Head

Wireless Charging Covers

KDB 648474 D03 (KDB 680106 D01)

Body & Head

FCC Specific Guidance - Module

Module manufacturers can add specific hosts that are used close to the body (or head) to the scope of their grant by performing SAR evaluations for that host.

Alternative allows manufacturer to perform SAR tests with the module and its antenna • If SAR values exceed a specific value then module may be limited

to a certain platform or a specific host• Test separation distance used may further limit the hosts allowed• SAR data is specific to the antenna used – small changes in

antenna can have a big impact on SAR

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Modular (host-independent) SAR tests - General (KDB 447498): Test separation distance, Xmm, ≤ 5mm

• SAR value ≤ 0.4 W/Kg- Module can be used in any portable host that will be at least Xmm from the

head/body provided energy coupling test SAR < 0.45 W/Kg.

• SAR value > 0.4 W/kg and ≤ 0.8 W/kg- Additional test in host platform with SAR value ≤ 0.8 W/kg allows use in the type of

platform

• SAR value > 0.8 W/kg and ≤ 1.2 W/kg- Additional test in host with SAR value ≤ 1.2 W/kg allows use in that host

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Modular (host-independent) - Laptops and tablets (KDB 616217): • Test separation distance ≤ 5mm

• SAR value < 0.8 W/Kg• Antenna may be located in the keyboard section of a laptop• In a tablet where the antenna-to-enclosure distance > twice test separation

distance

• Test separation distance ≤ 25mm

• SAR value < 0.8 W/Kg• Antenna may be located in the display section of a laptop

• SAR value > 0.8 W/Kg, < 1.2 W/Kg

• Additional test in a typical host allows use in that platform (tablet or laptop) if• SAR < 1.2W/Kg in the host test and module test• Separation distances in host tested represent most conservative (smallest)

distances for other devices

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FCC Case Study - Tablet/Pad ,10x15x0.9cm, with 3GPP, Wireless LAN & BT Need to know diagonal dimension to determine appropriate KDB guidance (tablet or UMPC device)

KDB 616217 is for devices with diagonal > 20cm KDB941225 UMPC for mini-tablets with diagonal < 20cm

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10cm

15cm

18cm

WLAN

3GPP

Bluetooth

Edge 1

Edge 3

Edge 2

Edge 4

FCC Case Study - Tablet/Pad ,10x15x0.9cm, with 3GPP, Wireless LAN & BT

KDB 941225 D07 UMPC Mini Tablet v01r01 What are requirements ? • Body SAR evaluated with device-to-phantom separation of 5mm

• FCC may allow 10mm separation –have to consult FCC

• Extremity SAR evaluation at 0mm separation not required unless body SARevaluated at 10mm.

• Test each edge/side where antenna is within 25mm of that surface• If held-to-ear use might be supported also apply head SAR testing• If device uses some proximity sensor or other mechanism to reduce

power when an edge/surface is close to the body

• Test at 5mm with power reduction enabled

• Test at 1mm less than the sensor trigger distance at full power

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Stand-alone SAR exclusion thresholds

• For each transmitter determine if SAR measurement is required for aseparation distance of 5mm

• Typically required for Wireless LAN and 3GPP but not Bluetooth

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Stand-alone SAR measurements and estimated values • Estimate value for Bluetooth

• Rear, Front, Edge 3, Edge 4

• 9mW output power

• 5mm separation distance

• Value = 0.37 W/Kg

• Measure SAR for 3GPP

• Rear, Front, Edge 2, Edge 3• Measure SAR for WLAN

• Rear, Front, Edge 1, Edge 4

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Edge 1

Edge 3

Edge 2

Edge 4


Simultaneous SAR - Calculate total rf exposure hazard presented by combination of transmitters:

Step 1 – simple summation for each edge/surface

• Rear of device: WLAN + 3GPP + Bluetooth

• Front of device: WLAN + 3GPP + Bluetooth

• Edge 1: No (WLAN only)

• Edge 2: No (3GPP only)

• Edge 3: Bluetooth + 3GPP

• Edge 4: Bluetooth + WLAN

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Edge 1

Edge 3

Edge 2

Edge 4


Step 2:

• If sum SAR > 1.6 W/Kg evaluate SPLSR- For rear evaluate SPLSR for all three combinations

• WWAN + Bluetooth• WLAN + Bluetooth• WWAN + WLAN

- For all edges just two transmitters

• If Bluetooth estimated value causes sum SAR to exceed 1.6W/Kg orSPLSR to exceed 0.04 you would measure the SAR value and use thereported SAR value in Step 1 and Step 2

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If SARWLAN + SAR3G + SARBT > 1.6W/Kg

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(SAR1 + SAR2)1.5 /R ≤ 0.04 to avoid volume scan or measuring Bluetooth SAR: • SARBT = 0.37W/Kg (estimated)• SAR3G < 1.6W/Kg, SARWLAN < 1.6W/Kg• (SAR3G + SARBT)1.5/100 ≤ 0.04 => SAR3G + SARBT ≤ 2.52 W/Kg • (SARWLAN + SAR3G)1.5 /136 ≤ 0.04 => SARWLAN + SAR3G ≤ 3.09 W/Kg (probably)

• (SARWLAN + SARBT)1.5/ 63 ≤ 0.04 => SARWLAN + SARBT ≤ 1.85 W/Kg (probably)

136mm

100mm

63mm


Step 3:

• For any surface where sum SAR > 1.6 W/Kg AND SPLSR > 0.04, volumescan is required

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THANK YOU.

Documents

Body SAR and FCC...GSM, GPRS, EDGE KDB 941225 D03 GSM, E-GPRS, EDGE Dual Transfer Mode (DTM) KDB 941225 D04 LTE KDB 941225 D05 FCC Specific Guidance - Platform 13 Device Type KDB Exposure