CSL CS101-2 EPC CLASS 1 GEN 2 RFID HANDHELD READER
USER'S MANUAL, VERSION 1.0
Copyright © Convergence Systems Limited, All Rights Reserved
211
Radio Frequency Radiation Exposure Evaluation
─
RFID Mode:
The measured highest RF output power of the EUT feeding to the embedded antenna was
28.6dBm at 927.25MHz. According to §1.1310 of the FCC rules, the power density limit for
General Population/Uncontrolled Exposure at 927.25 MHz is f
(MHz)
/1500 = 0.6182mW/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 the antenna (linear gain)
R = Distance from the antenna
For the EUT, the calculation is as follows:
P = 28.6dBm = 724.4mW
G = Maximum Antenna Gain = 5.5dBi = anti-log(5.5/10) = 3.55
At 20cm separation,
2
)
20
(
4
55
.
3
4
.
724
π
×
=
S
=
0.5116mW/cm
2
Based on the above calculation for 20cm separation, the power density does not exceed FCC
limit of 0.6182mW/cm
2
.
