User's Manual

CSL CS101-2 EPC CLASS 1 GEN 2 RFID HANDHELD READER USER'S MANUAL, VERSION 1.0
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212
Radio Frequency Radiation Exposure Evaluation ─ WiFi Mode:
The measured highest RF output power of the EUT feeding to the embedded antenna was
11.5dBm at 2412MHz. According to §1.1310 of the FCC rules, the power density limit for
General Population/Uncontrolled Exposure at 2412MHz is = 1.0 mW/cm
2
. The maximum
permissible exposure (MPE) is calculated to show the required separation distance that must be
maintained during installation to maintain compliance with the power density limit.
The following formula was used to calculate the Power Density:
2
4
R
PG
S
π
=
where:
S = Power density
P = Power feeding to the embedded patch antenna
G = Tx gain of antenna (linear gain)
R = Distance from the antenna
For the EUT, the calculation is as follows:
P = 11.5dBm = 14.13mW
G = Maximum Antenna Gain = 1.6dBi = anti-log(1.6/10) = 1.445
At 20cm separation,
2
)20(4
445.113.14
π
×
=S
=0.004062mW/cm
2
Based on the above calculation for 20cm separation, the power density does not exceed FCC
limit of 1.0mW/cm
2
.