RF Exposure Exhibit

FCC ID: LDK102061

RF Exposure Info

Download: PDF
FCCID_784213

Custom EMC Test Report No: EDCS - 571566




Maximum Permissible Exposure (MPE) Calculations
15.407: 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



                                               Page No: 174 of 221

   This document is uncontrolled. Please refer to the electronic copy within EDCS for the most up to date version.
                                     Cisco Systems, Inc. Company Confidential


Custom EMC Test Report No: EDCS - 571566




        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)
            5180       54       1       14.4      6      2.95    20   17.05
            5260       54       1       20.3      6      5.82    20   14.18
            5320       54       1       20.3      6      5.82    20   14.18
            5500       54       1       20.4      6      5.89    20   14.11
            5600       54       1       20.6      6      6.03    20   13.97
            5700       54       1       19.8      6      5.50    20   14.50
            5745       54       1       20.1      9      8.04    20   11.96
            5785       54       1       20.2      9      8.13    20   11.87
            5825       54       1       20.4      9      8.32    20   11.68
        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)
       5180      54       20      14.4      6       0.02       1        0.98
       5260      54       20      20.3      6       0.08       1        0.92
       5320      54       20      20.3      6       0.08       1        0.92
       5500      54       20      20.4      6       0.09       1        0.91
       5600      54       20      20.6      6       0.09       1        0.91
       5700      54       20      19.8      6       0.08       1        0.92
       5745      54       20      20.1      9       0.16       1        0.84
       5785      54       20      20.2      9       0.17       1        0.83
       5825      54       20      20.4      9       0.17       1        0.83




                                               Page No: 175 of 221

   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: 2007-04-23 12:27:26
Document Modified: 2007-04-23 12:27:26

© 2024 FCC.report
This site is not affiliated with or endorsed by the FCC