RF Exposure Info

FCC ID: Q87-WRT610NV1

RF Exposure Info

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FCCID_988069

RF EXPOSURE REPORT REPORT NO.: SA970423H02B MODEL NO.: WRT610N V1 ACCORDING: FCC Guidelines for Human Exposure IEEE C95.1 APPLICANT: Cisco-Linksys LLC ADDRESS: 121 Theory Drive Irvine, CA 92617(USA) ISSUED BY: Advance Data Technology Corporation LAB LOCATION: No. 81-1, Lu Liao Keng, 9 Ling, Wu Lung Tsuen, Chiung Lin Hsiang, Hsin Chu Hsien, Taiwan, R.O.C. Report No.: SA970423H02B 1 Reference No.: 970814H03

RF Exposure Measurement 1. Introduction In this document, we try to prove the safety of radiation harmfulness to the human body for our product. The limit for Maximum Permissible Exposure (MPE) specified in FCC 1.1310 is followed. The Gain of the antenna used in this product is measured in a Fully Anechoic Chamber (FAC) calibrated for antenna measurement in ADT, and also the maximum total power input to the antenna is measured. Through the Friis transmission formula and the maximum gain of the antenna, we can calculate the distance, away from the product, where the limit of MPE is reached. Although the Friis transmission formula is a far field assumption, the calculated result of that is an over-prediction for near field power density. We will take that as the worst case to specify the safety range. 2. RF Exposure Limit According to FCC 1.1310: The criteria listed in the following table shall be used to evaluate the environmental impact of human exposure to radio-frequency (RF) radiation as specified in 1.1307(b) LIMITS FOR MAXIMUM PERMISSIBLE EXPOSURE (MPE) Frequency Electric Field Magnetic Field Power Density Average Time Range Strength (V/m) Strength (A/m) (mW/cm2) (minutes) (MHz) (A)Limits For Occupational / Control Exposures 300-1500 … … F/300 6 1500-100,000 … … 5 6 (B)Limits For General Population / Uncontrolled Exposure 300-1500 … … F/1500 6 1500-100,000 … … 1.0 30 F = Frequency in MHz Report No.: SA970423H02B 2 Reference No.: 970814H03

3. Friis Formula Friis transmission formula : Pd = (Pout*G) / (4*pi*r2) where Pd = power density in mW/cm2 Pout = output power to antenna in mW G = gain of antenna in linear scale Pi = 3.1416 R = distance between observation point and center of the radiator in cm Pd is the limit of MPE, 1 mW/cm2. If we know the maximum Gain of the antenna and the total power input to the antenna, through the calculation, we will know the MPE value at distance 20cm. Ref. : David K. Cheng, Field and Wave Electromagnetics, Second Edition, Page 640, Eq. (11-133). 4. EUT Operating condition The software provided by Manufacturer enabled the EUT to transmit and receive data at lowest, middle and highest channel individually. 5. Classification The antenna of this product, under normal use condition, is at least 20cm away from the body of the user. Warning statement to the user for keeping at least 20cm or more separation distance with the antenna should be included in users manual. So, this device is classified as Mobile Device Report No.: SA970423H02B 3 Reference No.: 970814H03

6. Test Results 6.1 Antenna Gain 1. There three antennas provided to this EUT, please refer to the following table: Transmitter Antenna For 2.4GHz For 5GHz Antenna Note Circuit Type Gain (dBi) Gain (dBi) Connector Chain(0) PIFA 0.75 3 NA With TX & RX function Chain(1) PIFA 1.5 2.23 NA With TX & RX function Chain(2) PIFA 3.5 2.5 NA Only RX function 6.2 Output Power Into Antenna & RF Exposure value at distance 20cm: For 15.247(2.4GHz) : For Part 802.11b: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 2412 47.863 0.013 1.0 6 2437 63.096 0.018 1.0 11 2462 66.069 0.019 1.0 For Part 802.11g: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 2412 113.778 0.032 1.0 6 2437 117.800 0.033 1.0 11 2462 89.336 0.025 1.0 DRAFT 802.11n (20MHz) OFDM Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 2412 111.188 0.031 1.0 6 2437 117.768 0.033 1.0 11 2462 90.377 0.025 1.0 DRAFT 802.11n (40MHz) OFDM Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 2422 70.962 0.020 1.0 4 2437 113.778 0.032 1.0 7 2452 78.966 0.022 1.0 Report No.: SA970423H02B 4 Reference No.: 970814H03

For 15.247(5GHz) : For Part 802.11a: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 5745 322.372 0.128 1.0 3 5785 411.430 0.163 1.0 4 5805 433.159 0.172 1.0 For DRAFT 802.11n (20MHz) OFDM: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 5745 333.022 0.132 1.0 3 5785 419.251 0.166 1.0 4 5805 437.398 0.174 1.0 DRAFT 802.11n (40MHz) OFDM Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 5755 249.080 0.099 1.0 3 5795 440.855 0.175 1.0 Report No.: SA970423H02B 5 Reference No.: 970814H03

For 15.407(5GHz) : For Part 802.11a: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 5180 28.746 0.011 1.0 2 5200 29.076 0.012 1.0 4 5240 27.073 0.011 1.0 For DRAFT 802.11n (20MHz) OFDM: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 5180 17.755 0.007 1.0 2 5200 17.303 0.007 1.0 4 5240 21.611 0.009 1.0 DRAFT 802.11n (40MHz) OFDM Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2) (MHz) (mW/cm2) 1 5190 32.431 0.013 1.0 2 5230 30.563 0.012 1.0 CONCULSION: Both of the 11g and 11a can transmit simultaneously, the formula of calculated the MPE is: CPD1 / LPD1 + CPD2 / LPD2 + ……etc. < 1 CPD = Calculation power density LPD = Limit of power density Therefore, the calculation of this situation is 0.033 / 1 + 0.175 / 1 = 0.208, which is less than the “1” limit. Report No.: SA970423H02B 6 Reference No.: 970814H03


Document Created: 2008-08-19 19:17:02
Document Modified: 2008-08-19 19:17:02
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