mpe calculations

FCC ID: R68XSDRWLSG

RF Exposure Info

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FCCID_718924

                                                      MPE Calculations
Systems operating under the provision of 47 CFR 1.1307(b)(1) shall be operated in a manor that ensures that
the public is not exposed to radio frequency energy levels in excess of the FCC guidelines.

The EUT will only be used with a separation of 20 centimeters or greater between the antenna and the body of
the user or nearby persons and can therefore be considered a mobile transmitter per 47 CFR 2.1091(b). The
MPE calculation for this exposure is shown below.

Using the Antennas with highest output power:

The peak radiated output power (EIRP) is calculated as follows:
                                                      Power input to the   Power gain of the       EIRP             EIRP
                                  Frequency             antenna (P)          antenna (G)           (P+G)          Log-1(dBm/10)
          Antenna                   (GHz)                  (dBm)                 (dBi)             (dBm)            (mW)
          Wanshih
                                       2.4                  20.49                 2.89             23.38              217.77
        (PN: WSS003)

EIRP = P + G
Where
P = Power input to the antenna (mW).
G = Power gain of the antenna (dBi)

The numeric gain (G) of the antenna with a gain specified in dB is determined by:
                                                                            Antenna Gain               Numeric Antenna Gain
                                             Frequency                           (G)                       Log-1(dBm/10)
          Antenna                              (GHz)                            (dBi)                          (dB)
          Wanshih
                                                2.4                               2.89                         1.95
        (PN: WSS003)

G = Log-1 (dB antenna gain/10)

Power density at the specific separation:
                                                                     Numeric Power        Maximum Power       Maximum Power
                                                 Power input to       Gain of the         Spectral Density    Spectral Density
                                 Frequency      the antenna (P)       Antenna (G)          S=PG/(4R2π)             Limit
          Antenna                  (GHz)             (mW)                (dB)                (mW/cm2)            (mW/cm2)
          Wanshih
                                    2.4                111.94              1.95                0.043                  1.00
        (PN: WSS003)

S = PG/(4R2π)
Where
S = Maximum power density (mW/cm2)
P = Power input to the antenna (mW).
G = Numeric power gain of the antenna
R = Distance to the center of the radiation of the antenna (20cm = limit for MPE)

The maximum permissible exposure (MPE) for the general population is 1mW/cm2.

The power density at 20cm does not exceed the 1mW/cm2 limit. Therefore, the exposure condition is compliant with FCC rules.



Document Created: 2006-07-31 09:03:56
Document Modified: 2006-07-31 09:03:56

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