MPE

FCC ID: 2AJUZ76052

RF Exposure Info

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FCCID_3211060

RF Exposure Evaluation For FCC ID: 2AJUZ76052


Refer user manual this device is a RHF76-052 Module, and this device was designed used in
Mobile devices that the minimum distance between human’s body is 20cm. Based on the 47CFR
2.1091, this device belongs to Mobile device. The definition of the category as following:

Mobile Derives:
CFR Title 47 §2.1091(b)
(b) For purposes of this section, a mobile device is defined as a transmitting device designed to be
used in other than fixed locations and to generally be used in such a way that a separation distance of
at least 20 centimeters is normally maintained between the transmitter’s radiating structure(s) and the
body of the user or nearby persons.
FCC KDB 447498 D01 General RF Exposure Guidance v06 Limit

Devices operating in standalone mobile exposure conditions may contain a single transmitter or
multiple transmitters that do not transmit simultaneously. A minimum test separation distance ≥ 20 cm
is required between the antenna and radiating structures of the device and nearby persons to apply
mobile device exposure limits.        The distance must be fully supported by the operating and
installation configurations of the transmitter and its antenna(s), according to the source-based
time-averaged maximum power requirements of § 2.1091(d)(2). In cases where cable losses or
other attenuations are applied to determine compliance, the most conservative operating
configurations and exposure conditions must be evaluated. The minimum test separation distance
required for a device to comply with mobile exposure conditions must be clearly identified in the
installation and operating instructions, for all installation and exposure conditions, to enable users
and installers to comply with RF exposure requirements. For mobile devices that have the potential to
operate in portable device exposure conditions, similar to the configurations described in §
2.1091(d)(4), a KDB inquiry is required to determine the SAR test requirements for demonstrating
compliance.

When the categorical exclusion provision of § 2.1091(c) applies, the minimum test separation
distance may be estimated, when applicable, by simple calculations according to plane-wave
equivalent conditions, to ensure the transmitter and its antenna(s) can operate in manners that meet
or exceed the estimated distance. The source-based time-averaged maximum radiated power,
according to the maximum antenna gain, must be applied to calculate the field strength and power
density required to establish the minimum test separation distance.        When the estimated test
separation distance becomes overly conservative and does not support compliance, MPE
measurement or computational modeling may be used to determine the required minimum separation
distance.


According to FCC Part 1.1307, systems operating under the provisions of this section shall be
operated in a manner the ensures that the public is not exposed to radio frequency energy level in
excess of the commission’s guidelines.
                        Limits for General Population/ Uncontrolled Exposure
     Frequency Range              Electric Field           Magnetic Field             Power Density
          (MHz)                 Strength(E)(V/m)          Strength (H)(A/m)            (S)(mW/cm2)
           0.3-1.34                   614                         1.63                    (100)*
           1.34-30                   824/f                     2.19/f                    (180/f2)*
           30-300                     27.5                     0.073                        0.2
         300-1500                                                                         f/1500
       1500-100,000                                                                         1.0
MPE calculation formula




Where:
S = power density
P = output power (mW)
G = power gain of the antenna in the direction of interest relative to an isotropic radiator
R = Separation distance between radiator and human body (cm)

Peak Power Test Data
   Modulation Technology                                           DTS
      Modulation Type                                             LoRa
           Channel                     Low                     Middle                       High
    Frequency (MHz)                    903                     909.4                       914.2
     Peak Power (dBm)                 13.71                    13.38                       13.72
  Note: This report listed the worst case peak power value, please refer to RF test report for more
  details.


   Modulation Technology                     Frequency hopping system & Hybrid system
      Modulation Type                                             LaRa
           Channel                     Low                     Middle                       High
    Frequency (MHz)                   902.3                    908.7                       914.9
     Peak Power (dBm)                 13.63                    13.59                       13.67
  Note: This report listed the worst case peak power value, please refer to RF test report for more
  details.


Test result
                       Maximum      Antenna                               Limit of
                                                  Total                                Power
   Evolution          peak output     Gain                Distance         Power
                                                 Power                                Density         Verdict
    mode                power       (typical)               (cm)          Density
                                                 (mw)                                (mW/cm²)
                       (dBm)          (dBi):                             (mW/cm²)
    GFSK                13.72         -2.0       14.85       20            0.61      3.00 x 10-3      Pass
     FSK                13.67         -2.0       14.68       20            0.61      2.92 x 10   -3
                                                                                                      Pass


Note:
1. The RHF1S001 IP64 T&H sensor work frequency range used is 902 MHz ~ 928 MHz, the result
   close to the limit by the above formula so, we select 914.2 MHz and 914.9 MHz to calculate the
   exclusion power threshold.
2. More power list please refer to RF test report.



Document Created: 2019-07-21 15:33:32
Document Modified: 2019-07-21 15:33:32

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