MPE Analysis Report
Product Description
The Equipment Under Test (EUT) is a Wi-Fi and BLE enabled humidity controller designed to provide timed regulation of humidity. The EUT is powered by 120VAC.
MPE Evaluation Context
For Maximum Permissible Exposure (MPE) evaluation of the unit, the maximum power density at 20 cm from this transmitter shall be less than the General Population / Uncontrolled MPE limit in OET Bulletin 65 and meet the requirement listed in KDB447498 D04 v01.
For the 2.4GHz RF portion of the unit, the measured powers among all the measured channels were within its production tolerance. The maximum source-based time-averaging duty factor is 100%. From these data and its operating configuration, the exposed power density at a distance (R) of 20 cm from the center of radiation of the antenna can be calculated according to OET Bulletin 65 as follow:
BLE Portion Details
Antenna Type: Internal, integral
Antenna Gain: 2.54dBi
Nominal Conducted Power: -17.0dBm
Range of Peak Conducted Power: -20dBm to 10dBm
Wi-Fi Portion Details
The Wi-Fi portion was tested in accordance with the following power output and in actual application the below limit shall not be exceeded.
| Operating Mode | Nominal Power | Range of Peak Conducted Power |
|---|---|---|
| 802.11b | 18.4dBm | 10dBm to 20dBm |
An internal, integral antenna has been used.
Antenna Gain: 2.54dBi
MPE Calculations
For Maximum Permissible Exposure (MPE) evaluation of the EUT, the maximum power density at 20 cm from this mobile transmitter shall be less than the General Population / Uncontrolled MPE limit in OET Bulletin 65.
BLE Portion Calculation
Maximum conducted power was 10dBm. The distance (D) between the antenna and the equipment under test (EUT) was 3 meters. The maximum source-based time-averaging duty factor is 100%. Exposed power density at a distance (R) of 20cm from the center of radiation of the antenna is calculated as follows:
The radiated power = 10dBm + 2.54dBi = 12.54dBm (17.95 mW)
The radiated (EIRP) source-based time-averaging output power = (17.95 * 1) mW = 17.95 mW
The power density at 20 cm from the antenna = EIRP / 4πR^2 = 0.003571 mW cm-2
Wi-Fi Portion Calculation
Maximum conducted power was 20dBm. The distance (D) between the antenna and the equipment under test (EUT) was 3 meters. The maximum source-based time-averaging duty factor is 100%. Exposed power density at a distance (R) of 20cm from the center of radiation of the antenna is calculated as follows:
The radiated power = 20dBm + 2.54dBi = 22.54dBm (179.47 mW)
The radiated (EIRP) source-based time-averaging output power = (179.47 * 1) mW = 179.47 mW
The power density at 20 cm from the antenna = EIRP / 4πR^2 = 0.035704 mW cm-2
MPE Limit and Compliance
In the frequency range of 1,500 - 100,000MHz, the MPE limit is 1.0 mWcm-2 for general population and uncontrolled exposure. As the measured power density at 20cm from the transmitter is lower than the MPE limit, compliance can be ensured by indicating the minimum 20cm separation between the transmitter's radiating structures and the user's body or nearby persons.
FCC RF Radiation Exposure Statement
Caution: To maintain compliance with the FCC's RF exposure guidelines, place the unit at least 20cm from nearby persons.
Simultaneous Transmission Evaluation
For this product with multiple transmitters and antennas (BLE and Wi-Fi portions), the requirement of Simultaneous Transmission evaluation has been considered and complied with the following conditions of the worst case:
MPE1/Limit1 + MPE2/Limit2 ≤ 1
Thus:
0.003571 / 1 (BLE portion) + 0.035704 / 1 (Wi-Fi portion) = 0.039275
It is concluded that no Simultaneous Transmission evaluation is required.
Product Identification
FCC ID: 2AYZD-200WIFI
