RF Exposure Info

FCC ID: BCGA1991

RF Exposure Info

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FCCID_4492791

                        RF EXPOSURE EVALUATION REPORT


                                                             For: Apple Inc.

                                                           Product: A1991

                                                         FCC ID: BCGA1991


                                       RF Exposure Evaluation Report Serial No.:
                                              UL/REGA1/MPE12718494B




 This RF Exposure Evaluation Report Is Issued Under The Authority
 Of Alan Binks, Head of Inspection:




 PP:

 Written By: John Bellairs                                              Checked By: Andrew Hoare




 Report Copy No: PDF01                                                  Issue Date: 10 October 2019




This report may be reproduced in full. Partial reproduction may only be made with the written consent
of UL




UL VS Ltd
Unit 1-3, Horizon, Wade Road, Kingsland Business Park, Basingstoke, Hampshire, RG24 8AH, UK
T: +44 (0)1256 312000                     W: www.ul.com


UL                                             RF EXPOSURE EVALUATION REPORT
                                               No: UL/REGA1/MPE12718494B
                                               Page: 2 of 9
                                               Issue Date: 10 October 2019
For:           Apple Inc.
Product:       A1991

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UL                                                     RF EXPOSURE EVALUATION REPORT
                                                       No: UL/REGA1/MPE12718494B
                                                       Page: 3 of 9
                                                       Issue Date: 10 October 2019
For:           Apple Inc.
Product:       A1991



RF Exposure Evaluation for the A1991

The A1991 is a desktop computer which contains 2.4GHz and 5GHz WIFI and 2.4GHz Bluetooth BR/
EDR and LE transmitters.

WLAN supports 3x3 MIMO operation with beam forming, and there can be simultaneous transmission
between all of the transmitters.


The following FCC Rule Parts and procedures are applicable:
Part 1.1310 – Radiofrequency radiation exposure limits
Part 2.1091 – Radiofrequency radiation exposure evaluation: mobile devices


KDB447498 D01 v06 - Mobile and Portable Devices RF Exposure Procedures and Equipment
Authorisation Policies

KDB 662911 D01 v02 r01 – Multiple Transmitter Output


MAXIMUM TRANSMITTER POWER CONSIDERATIONS

From Tune Up tables (conducted power):
WLAN 2.4GHz:
Power (SISO) = 23.0dBm max
For non-beam forming MIMO, conducted power for each antenna:
Power (2x2MIMO) = 23.0dBm max (200mW)
Power (3x3 MIMO) = 23.0dBm max (200mW)
For BF MIMO:
Power (2x2MIMO) = 23.0dBm max (200mW)
Power (3x3MIMO) = 21.0dBm max (125.9mW)


ANTENNA GAINS:
Antenna Gain Ant0: +4.56dBi (x2.9)
Antenna Gain Ant1: +4.32dBi (x2.7)
Antenna Gain Ant2: +4.47dBi (x2.8)


From KDB 662911 D01 v02 r01., Max. beamforming max antenna gain is calculated as (see
Appendix):
For 2Tx BF = +7.53dBi (x5.66) (Ant0 & Ant2)
For 3Tx BF = +9.22dBi (x8.36)


UL                                                   RF EXPOSURE EVALUATION REPORT
                                                     No: UL/REGA1/MPE12718494B
                                                     Page: 4 of 9
                                                     Issue Date: 10 October 2019
For:          Apple Inc.
Product:      A1991



RADIATED POWER:
EIRPSISO0 = 27.56dBm = 570.2 mW
EIRPSISO1 = 27.32dBm = 539.5 mW
EIRPSISO2 = 27.47dBm = 558.5 mW


Powermax for non BF 2x2 MIMO operation:
EIRPMIMO2 = 27.56dBm + 27.47dBm = 570.2mW + 558.5mW = 1.13W


Power for 2Tx BF operation (23dBm + Ant0 & Ant2 antenna gain):
EIRPBF2 = 23dBm + 7.53dBi = 30.53dBm = 1.13W


Power for non BF 3x3 MIMO operation:
EIRPMIMO3 = 27.56dBm + 27.32dBm + 27.47dBm = 570.2mW + 539.5mW + 558.5mW = 1.67W*


Power for 3Tx BF operation (21dBm + ant gain):
EIRPBF3 = 21dBm + 9.22dBi = 30.22dBm = 1.05W


*max power to be considered in calculations


WLAN 5GHz:
Power = 22.0dBm max (For SISO + 2x2 MIMO + 3x3MIMO + 2 X TxBF)
Power = 20.0dBm max (For 3 X TxBF)


ANTENNA GAINS:
Antenna Gain Ant0: +6.06dBi
Antenna Gain Ant1: +5.71dBi
Antenna Gain Ant2: +4.93dBi


From KDB 662911 D01 v02 r01., Max. beamforming antenna gain is calculated as (see Appendix):
For 2TX BF = +8.9dBi (x7.76) (Ant0 & Ant1)
For 3Tx BF = +10.35dBi (x10.84)


RADIATED POWER:
EIRPSISO1 = 28.06dBm = 639.7 mW


UL                                                       RF EXPOSURE EVALUATION REPORT
                                                         No: UL/REGA1/MPE12718494B
                                                         Page: 5 of 9
                                                         Issue Date: 10 October 2019
For:          Apple Inc.
Product:      A1991

EIRPSISO2 = 27.71dBm = 590.2 mW
EIRPSISO3 = 26.93dBm = 493.2 mW


Power for non BF 2x2 MIMO operation:
EIRPMIMO2 = 28.06dBm + 27.71dBm = 639.7mW + 590.2mW = 1.23W


Power for 2TX BF operation (22dBm + WF2 & WF3 antenna gain):
EIRPBF2 = 22dBm +8.9dBi = 30.9dBm = 1.23W


Power for non BF 3x3 MIMO operation:
EIRPMIMO3 = 28.06dBm + 27.71dBm + 26.93dBm = 639.7mW + 590.2mW + 493.2mW= 1.72W*


Power for 3TX BF operation (20dBm + ant gain):
EIRPBF3 = 20dBm + 10.35dBi = 30.35dBm = 1.08W


*max power to be considered in calculations


Bluetooth (Basic Rate, EDR & Low Energy) 2.4GHz
Power conducted = 13.0dBm
Antenna Gain Ant 3: 4.5dBi
EIRP = 17.5dBm = 56.2mW



MPE CALCULATIONS
The MPE calculation used to calculate the safe operating distance for the user is.


                                           S = EIRP/4 π R2


Where         S = Power density
              EIRP = Effective Isotropic Radiated Power (EIRP = P x G)
              P = Conducted Transmitter Power
              G = Antenna Gain (relative to an isotropic radiator)
              R = distance to the centre of radiation of the antenna (20cm requirement).


UL                                                       RF EXPOSURE EVALUATION REPORT
                                                         No: UL/REGA1/MPE12718494B
                                                         Page: 6 of 9
                                                         Issue Date: 10 October 2019
For:           Apple Inc.
Product:       A1991

For WLAN 2.4GHz
Values:
Transmitter frequency range = 2412 MHz to 2472MHz
Max. EIRPSISO = 570.2 mW
EIRPMIMO = 1.67W
R = 20cm


Power Density Requirement
               From table 1 (b) - Limits for General Population/ Uncontrolled Exposure of
               FCC Rule Part 1.1310 for 2.4GHz

               Sreq1 = 1.0 mW/cm2


Calculation:
               S = EIRPSISO /4 π R2
               S = 570.2/(12.56 x 202)
               S = 570.2/ (5024)


                      S1 SISO = 0.11mW/ cm2 (<1.0 mW/cm 2)
Similarly for MIMO:   S1 MIMO = 0.33mW/ cm2 (<1.0 mW/cm 2)
This equates to minimum safe operating distance ( 3x3 MIMO operation) of 11.5 cm at the RF
exposure limit of 1.0 mW/cm2



For WLAN 5GHz
Values:
Transmitter frequency range = 5150 MHz to 5850MHz
Max. EIRPSISO = 639.7mW
EIRPMIMO = 1.72W
R = 20cm


Power Density Requirement
               From table 1 (b) - Limits for General Population/ Uncontrolled Exposure of
               FCC Rule Part 1.1310 for 5GHz

               Sreq2 = 1.0 mW/cm2


UL                                                       RF EXPOSURE EVALUATION REPORT
                                                         No: UL/REGA1/MPE12718494B
                                                         Page: 7 of 9
                                                         Issue Date: 10 October 2019
For:           Apple Inc.
Product:       A1991

Calculation:
               S = EIRPSISO /4 π R2
               S = 639.7/(12.56 x 202)
               S = 639.7/(5024)


                      S2 SISO = 0.13mW/ cm2 (<1.0 mW/cm 2)
Similarly for BF:     S2 MIMO = 0.34mW/ cm2 (<1.0 mW/cm 2)


This equates to minimum safe operating distance (3TX BF operation) of 11.7 cm at the RF
exposure limit of 1.0 mW/cm2


For Bluetooth 2.4 GHz
Values:
Transmitter frequency range = 2402 MHz to 2480MHz
EIRP = 56.23 mW
R = 20cm


Power Density Requirement
               From table 1 (b) - Limits for General Population/ Uncontrolled Exposure of
               FCC Rule Part 1.1310 for 5GHz


               Sreq3 = 1.0 mW/cm2
Calculation:
               S = EIRP/4 π R2
               S = 56.23/(12.56 x 202)
               S = 56.23/(5024)


               S3 = 0.011mW/ cm2 (<1.0 mW/cm 2)


This equates to a minimum safe operating distance of 2.1cm at the RF exposure limit of 1.0
mW/cm2


UL                                                             RF EXPOSURE EVALUATION REPORT
                                                               No: UL/REGA1/MPE12718494B
                                                               Page: 8 of 9
                                                               Issue Date: 10 October 2019
For:          Apple Inc.
Product:      A1991

KDB447498 D01 v05 Section 7.2 SIMULTANEOUS TRANSMISSION CONSIDERATIONS


Worst case summation of calculated MPE ratios for 2.4GHz/ 5GHz WLAN and 2.4GHz BT
simultaneously transmitting transmitters from each respective antenna is:


              ie:   ΣMPEratios = (S1 SISO/ Sreq1) + (S2 SISO/ Sreq2) + (S3 SISO/ Sreq3)
                               = (0.33/1.0) + (0.34/1.0) + (0.011/1.0)
                               = 0.68


Σ of MPE ratios<1.0, so in accordance with KDB447498 Section 7.2, simultaneous transmission test
exclusion applies for the WLAN and Bluetooth transmitters.


Conclusion
The required 20cm RF exposure limits for General Population/ Uncontrolled Exposure will not be
exceeded for the A1991 using antennas as specified.


UL                                                                         RF EXPOSURE EVALUATION REPORT
                                                                           No: UL/REGA1/MPE12718494B
                                                                           Page: 9 of 9
                                                                           Issue Date: 10 October 2019
For:          Apple Inc.
Product:      A1991


Appendix
Antenna gain calculation for BF operation:

From KDB 662911 D01 v02 r01:

For 2TX BF - Directional Gain =

                                𝑁𝐴𝑁𝑇          2
                         𝑁𝑆𝑆           𝑔𝑗,𝑘                                3        2
                         𝑗=1
                                𝑘=1                               1        𝑘=1 𝑔𝑗,𝑘
                                                                  𝑗=1
              10 log                                  = 10 log
                               𝑁𝐴𝑁𝑇                                        2


For 3TX BF - Directional Gain =


                                𝑁𝐴𝑁𝑇          2                                     2
                                                                           3
                         𝑁𝑆𝑆
                                𝑘=1    𝑔𝑗,𝑘                       1        𝑘=1 𝑔𝑗,𝑘
                         𝑗=1                                      𝑗=1
              10 log                                  = 10 log
                               𝑁𝐴𝑁𝑇                                        3



Example - 2.4GHz 3TX BF:
Antenna Gain Ant0: +4.56dBi (x2.9)
Antenna Gain Ant1: +4.32dBi (x2.7)
Antenna Gain Ant2: +4.47dBi (x2.8)

Directional Gain =

                                                                          𝐺1         𝐺2          𝐺3 2
                                                  2                     1020   +   1020   +   10 20
                       𝑔1,1 + 𝑔1,2 + 𝑔1,3
            10 log                                     = 10 log
                               3                                                     3

                                                      4.56       4.32          4.47 2
                                              10 20 + 10 20 + 10 20
                               = 10 log                                                   = 𝟗. 𝟐𝟐 𝐝𝐁𝐢
                                                                 3



Document Created: 2019-10-10 09:40:10
Document Modified: 2019-10-10 09:40:10

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