User's Manual

2 Avoiding Hazards
32
The applicable power density exposure limit from the documents referenced above is:
• 10 W/m
2
for RF energy in the 2.4-, 5.2-, 5.4-, 5.8- and 5.9 GHz frequency bands.
Peak power density in the far field of a radio frequency point source is calculated as follows:
Equation 1 - Peak power density in the far field
Where
Rearranging terms to solve for distance yields:
2.1.1.1 Calculated Distances and Power Compliance Margins
Table 3 shows calculated minimum separation distances d,
recommended distances and
resulting power compliance margins for each frequency band and antenna combination.
Table 3 - Power Compliance Margins
Variable Band Antenna Max
Average
Transmit
Power in
Burst
(Watt)
P
(Watt)
G S
(W/m
2
)
d
(m)
Recom-
mended
Distance
(m)
Power
Compliance
Margin
2.5
GHz
Integrated 0.25 0.125
63
(18dBi)
10 0.25 2 8.0
4.5
GHz
Integrated 0.5 0.4
63
(22dBi)
10 0.71 5 7.0
Integrated 0.5 0.4
63
(22dBi)
10 0.71 5 7.0
4.8
GHz
Connectorized 0.5 0.4 (26 dBi) 10 1.1 5 4.5
Integrated 0.25 0.2
63
(22dBi) 10 0.5 2 4.0
4.9
GHz
Connectorized 0.25 0.2 (26 dBi) 10 0.8 5 6.25
S = power density in W/m
2
P= Maximum Average transmit power capability of the radio, in W
G= total Tx gain as a factor, converted from dB
d = distance from point source, in m
2
4
.
d
GP
S
π
=
S
GP
d
.4
.
π
=