MPE calculations

FCC ID: R68WIPORTG

RF Exposure Info

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FCCID_671291

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 antenna antenna EIRP EIRP Frequency (P) (G) (P+G) Log-1(dBm/10) Antenna (GHz) (dBm) (dBi) (dBm) (mW) US Robotics 2.4 21.08 5.00 26.08 405.51 (PN: USR5481) 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) US Robotics 2.4 5.00 3.16 (PN: USR5481) G = Log-1 (dB antenna gain/10) Power density at the specific separation: Numeric Power Power input to Gain of the Maximum Power Maximum Power the antenna Antenna Spectral Density Spectral Density Frequency (P) (G) S=PG/(4R2π) Limit Antenna (GHz) (mW) (dB) (mW/cm2) (mW/cm2) US Robotics 2.4 128.23 3.16 0.081 1.00 (PN: USR5481) 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: 2006-06-15 10:42:11
Document Modified: 2006-06-15 10:42:11
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