rf exposure

FCC ID: 2AOFDLSD4BT-K5X

RF Exposure Info

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FCCID_4216547

RF Exposure Evaluation For FCC ID: 2AOFDLSD4BT-K5X

Refer user manual this device is a Bluetooth 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)

Test data
                                               Bluetooth
                                                             GFSK (BLE)
              Mode
                                      Low Channel             Middle Channel           High Channel
      Peak Power (dBm)                     10.19                    10.33                  10.39
  Note: This report listed the worst case peak power value, please refer to RF test report for more
  details.
Turn-up power
               Mode                                          Range (dBm)
             Bluetooth                                         9.00-11.00
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)
  Bluetooth            11.00        1.50       17.78        20              1        0.004        Pass
Note:
1. The Bluetooth Module work frequency range used is 2400 MHz ~ 2483.5 MHz, the result close to
   the limit by the above formula, so we select 2480MHz to calculate the exclusion power threshold.
2. More power list please refer to RF test report.

Conclusion:
RF exposure Evaluation Results: Compliance



Document Created: 2019-03-26 15:54:29
Document Modified: 2019-03-26 15:54:29

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