MPE

FCC ID: LDK102090P

RF Exposure Info

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FCCID_2050749

Maximum Permissible Exposure (MPE) Calculations For AIR-CAP1532I-A-K9 15.247: U-NII devices are subject to the radio frequency radiation exposure requirements specified in Sec. 1.1307(b), Sec. 2.1091 and Sec. 2.1093 of this chapter, as appropriate. All equipment shall be considered to operate in a ``general population/uncontrolled'' environment. Applications for equipment authorization of devices operating under this section must contain a statement confirming compliance with these requirements for both fundamental emissions and unwanted emissions. Technical information showing the basis for this statement must be submitted to the Commission upon request. 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) and s=((0.282*10^((P+G)/20))/d)^2 Equation (2) 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 are 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 supported antenna gain is 6 dBi (9dBi with beamforming). Using the peak power levels recorded in the test report along with Equation 1 above, the MPE distances are calculated as follows. 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 28.0 3 10.01 20 9.99 2437 11 1 29.0 3 11.23 20 8.77 2462 11 1 26.0 3 7.95 20 12.05 2412 54 1 17.0 3 2.82 20 17.18 2437 54 1 24.0 3 6.31 20 13.69 2462 54 1 18.0 3 3.16 20 16.84 MPE Calculations To maintain compliance, installations will assure a separation distance of at least 20cm. Using Equation 2, the MPE levels (s) at 20 cm are calculated as follows: Peak MPE Transmit Antenna Power Frequency Bit Rate Distance Power Gain Density Limit Margin (MHz) (Mbps) (cm) (dBm) (dBi) (mW/cm^2) (mW/cm^2) (mW/cm^2) 2412 11 20 28.0 3 0.25 1 0.75 2437 11 20 29.0 3 0.32 1 0.68 2462 11 20 26.0 3 0.16 1 0.84 2412 54 20 17.0 3 0.02 1 0.98 2437 54 20 24.0 3 0.10 1 0.90 2462 54 20 18.0 3 0.03 1 0.97


Document Created: 2013-08-20 08:25:22
Document Modified: 2013-08-20 08:25:22
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