MPE Calculation

FCC ID: LDK102055

RF Exposure Info

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FCCID_576970

FCC ID: LDK102055, Canada: 2461B-102055 Maximum Permissible Exposure (MPE) Calculations Given E=√(30*P*G)/d and S=E^2/3770 where E=Field Strength in Volts/meter P=Power in Watts G=Numeric Antenna Gain d=Distance in meters S=Power Density in mW/cm^2 Combine equations and rearrange the terms to express the distance as a function of the remaining variables: d=√((30*P*G)/(3770*S)) Changing to units of power in mW and distance in cm, using: P(mW)=P(W)/1000 d(cm)=100*d(m) yields d=100*√((30*(P/1000)*G)/(3770*S)) d=0.282*√(P*G/S) where d=Distance in cm P=Power in mW G=Numerica Antenna Gain S=Power Density in mW/cm^2 Substituting the logarithmic form of power and gain using: P(mW)=10^(P(dBm)/10) G(numeric)=10^(G(dBi)/10) yields d=0.282*10^((P+G)/20)/√S Equation (1) where d=MPE distance in cm P=Power in dBm G=Antenna Gain in dBi S=Power Density in mW/cm^2 Equation (1) and the measured peak power is used to calculate the MPE distance. Note that for mobile or fixed location transmitters such as an access point, the minimum separation distance is 20 cm even if the calculations indicate that the MPE distance may be less. S=1mW/cm^2 maximum. The highest 2.4GHz antenna gain supported is 10 dBi, and the highest 5 GHz antenna gain is 9.5 dBi. Using the peak power levels recorded in the test report along with Equation 1 above, the MPE distances are calculated as follows. Page No: 118 of 137 This document is uncontrolled. Please refer to the electronic copy within EDCS for the most up to date version. Cisco Systems, Inc. Company Confidential

FCC ID: LDK102055, Canada: 2461B-102055 Peak Power Transmit Antenna MPE Frequency Bit Rate Density Power Gain Distance Limit Margin (MHz) (Mbps) (mW/cm^2) (dBm) (dBi) (cm) (cm) (cm) 2412 11 1 20 10 8.92 20 11.08 2437 11 1 20 10 8.92 20 11.08 2462 11 1 20 10 8.92 20 11.08 2412 54 1 17 10 6.31 20 13.69 2437 54 1 17 10 6.31 20 13.69 2462 54 1 17 10 6.31 20 13.69 2.4GHz MPE Calculations Peak Power Transmit Antenna MPE Frequency Bit Rate Density Power Gain Distance Limit Margin (MHz) (Mbps) (mW/cm^2) (dBm) (dBi) (cm) (cm) (cm) 5180 54 1 11 9.5 2.99 20 17.01 5260 54 1 17 9.5 5.96 20 14.04 5320 54 1 11 9.5 2.99 20 17.01 5745 54 1 17 9.5 5.96 20 14.04 5785 54 1 14 9.5 4.22 20 15.78 5805 54 1 11 9.5 2.99 20 17.01 5GHz MPE Calculations Page No: 119 of 137 This document is uncontrolled. Please refer to the electronic copy within EDCS for the most up to date version. Cisco Systems, Inc. Company Confidential


Document Created: 2005-08-31 12:36:23
Document Modified: 2005-08-31 12:36:23
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