SL9090_RF Exposure report_02

FCC ID: N7NSL9090

RF Exposure Info

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FCCID_1776910

Evaluation of RF Exposure for SL9090 Wireless Modem as a Mobile Device In this application we seek modular approval to the SL9090 wireless modem for use in mobile configuration. Part I: FCC requirement Based on the FCC OET Bulletin 65 Supplement C and 47 CFR §2.1091, we have concluded that the SL9090 will comply with the FCC rules on RF exposure for mobile devices if the antenna gain does not exceed 7.5 dBi in cellular band and 3.5 dBi in PCS band. The following analysis will demonstrate such compliance. The analysis will be done in two US bands. Operation in cellular band (824 – 849 MHz) The peak conducted output power of SL9090 in Cellular band is 32.61 dBm. Take the worst case as an example, in which an antenna with 7.5 dBi gain is used. The resulted power density at a distance of 20 cm can be deducted as follows: EIRP = Pcond + 7.5 Power Density = EIRP*DutyCycle/(4πR2) The table below shows the different MPE levels in different time slot configurations: Max Pcond Max EIRP Max EIRP Dute Cycle (dBm) (dBm) (mW) MPE (mW/ cm2) 1 Time Slot 32.44 39.94 9862.79 12.5% 0.245 2 Time Slots 32.61 40.11 10256.52 25% 0.510 The MPE limit for General Population/Uncontrolled Exposure is shown in the FCC OET Bulletin 65 Supplement C and can be calculated as follows: MPE limit = 824/1500 = 0.55 mW/cm2 As we can see the resulted power density is below the MPE limit, therefore SL9090 in Cellular band is compliant with the FCC rules on RF exposure. Operation in PCS band (1850 – 1910 MHz) The peak conducted output power of SL9090 in PCS band is 29.4 dBm. Take the worst case as an example, in which an antenna with 3.5 dBi gain is used. The resulted ERP can be expressed as follows: ERP = 29.4 + 3.5 –2.15 = 30.75 dBm (1.19 W) < 3 W The FCC OET Bulletin 65 Supplement C states that mobile devices identified in 47 CFR §2.1091 that operate at frequencies above 1.5 GHz with an ERP of 3.0 watts or more are required to perform routine environmental evaluation for RF exposure prior to equipment authorization or use; otherwise, they are categorically excluded.

As we can see this resulted ERP is below 3 W, therefore routine environmental evaluation for RF exposure prior to equipment authorization or use for SL9090 in PCS band is categorically excluded. Part II: IC requirement Power Density= 0.515m W/cm2 =5.15W/ m2 (Worse case) When operate in cellular band (824 – 849 MHz) if the device antenna gain does not exceed 7.5 dBi in cellular band. (Please list the power density calculation base on cellular peak power) Power Density= 0.097m W/cm2 =0.97W/ m2 (Worse case) When operate in PCS band (1850 – 1910 MHz) if the device antenna gain does not exceed 3.5 dBi in PCS band. (Please list the power density calculation base on PCS peak power) The table below shows the different MPE levels in different time slot configurations: Max Pcond Max EIRP Max EIRP Dute Cycle (dBm) (dBm) (mW) MPE (mW/ cm2) 1 Time Slot 29.4 32.9 1949.84 12.5% 0.048 2 Time Slots 29.4 32.9 1949.84 25% 0.097 AS IC RSS-102 requirement, RF Field Strength Limits for Devices Used by the General Public (Uncontrolled Environment) listed below: Frequency Range Electric Field (V/m Magnetic Field (A/m Power Density Averaging Time 2 (MHz) rms) rms) (W/ m ) (minutes) 0.003-1 280 2.19 - 6 1-10 280/f 2.19/f - 6 10-30 28 2.19/f - 6 30-300 28 0.073 2* 6 300-1500 1.585 f 0.5 0.0042 f 0.5 f/150 6 1500-15000 61.4 0.163 10 6 15000-150000 61.4 0.163 10 616000/f 1.2 150000-300000 0.158 f 0.5 4.21 x 10-4 f 0.5 6.67 x 10-5 f 616000/f 1.2 Note: f is frequency in MHz. * Power density limit is applicable at frequencies greater than 100 MHz. The RF Field Strength limit for General Population/Uncontrolled Exposure is shown in the RSS- 102 and can be calculated as follows: Cellular band limit = 824/150 = 5.5 W/m2 PCS band limit =10W/ m2 As we can see the resulted power density is below the MPE limit, therefore SL9090 is compliant with the IC rules on RF exposure.


Document Created: 2012-08-09 10:51:44
Document Modified: 2012-08-09 10:51:44
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