Attachment WVU Radiation Study SES-LIC-20111219-01468

Attachment WVU Radiation Study

This document pretains to SES-LIC-20111219-01468 for License on a Satellite Earth Station filing.

IBFS_SESLIC2011121901468_930091

Exhibit
No.
WVU
1

RADIATION
HAZARD
STUDY

For

West
Virginia
University

This
report
is
to
analyze
the
non-‐ionizing
radiation
levels
for
a
Transportable
Ku
Uplink
utilizing

the
MEAS
(2-‐port),
2.4
meter
Earth
Station
Antenna.
The
Office
of
Science
and

Technology
Bulletin,
No.
65,
August
1997,
specified
that
the
maximum
level
of
non-‐ionizing

radiation
that
a
person
may
be
exposed
to
over
a
.1
hour
(6
minute)
period
is
an
average
power

density
equal
to
5mW/cm^2
(five
mill
watt
per
centimeter
squared).
It
is
the
purpose
of
this

report
to
ascertain
the
power
flux
densities
of
the
earth
station
in
the
far
field,
near
field,

transition
region,
the
main
reflector
surface,
and
between
the
antenna
edge
and
the
ground.

The
following
parameters
were
used
to
calculate
the
various
power
flux
densities
for
the
earth

station:

Antenna
Diameter,
(D)

=
2.4

meters

Antenna
Surface
Area,
(Sa)

=
p(D^2)/4

=
4.5239
m^2

Wavelength
at
14.25
Ghz,
(λ)

=
300/F

=
0.0211
meters

Transmit
Power
at
Flange,
(P)

=
100
watts

Antenna
Gain,
(Ges)

=
48.9dbi

Antenna
gain
at
14.3GHz
=
48.9dBi,
converted
to
a

power
ratio
given
by:
Ges=10
^
dBi/10

Antenna
Gain
Factor
(G)

=77624.7117

p

=
3.1415927

Antenna
Aperture
Efficiency,
(n)

=
G(λ^2)/(p2D^2)
=0.6052

ANSI
Safe
Power
Density,
(Ws)

=
5.0mW/cm^2

Exhibit
No.
WVU
1

I. Far
Field
Calculations

The
distance
to
the
beginning
of
the
far
field
region
can
be
found
by
the
following

equation:

Distance
to
the
Far
Field
Region,
(Rf)
=
(0.6(D^2))/λ

=
164.16
meters

The
maximum
main
beam
power
density
in
the
far
field
can
be
calculated
as
follows:

Far
Field
On-‐axis
power
density,
(Wf)

=
((Ges)(P))/(4
p
(Rf^2))

=
22.9222
W/m^2

=
2.2922
mW/cm^2

II. Near
Field
Calculations

Power
flux
density
is
considered
to
be
at
a
maximum
value
throughout
the
entire
length

of
the
defined
region.
The
region
is
contained
within
a
cylindrical
volume
having
the

same
diameter
as
the
antenna.
Past
the
extent
of
the
near
field
region,
the
power

density
decreased
with
distance
from
the
transmitting
antenna.

The
distance
to
the
end
of
the
near
field
can
be
determined
by
the
following
equation:

Extent
of
Near
Field,
(Rn)

=
D^2/4λ

=
68.4
meters

The
maximum
power
density
in
the
near
field
is
determined
by:

Near
Field
On-‐axis
power
density,
(Wn)

=
(16(n)P)/(
p
(D^2))

=
53.5104
W/m^2

=
5.351
mW/cm^2

Exhibit
No.
WVU
1

VI.
Off-‐axis
Evaluation

For
off-‐axis
calculations
in
the
near-‐field
and
in
the
transition
region,
it
can
be
assumed

that,
if
the
point
of
interest
is
at
least
one
antenna
diameter
removed
from
the
center
of

the
main
beam,
the
power
density
at
that
point
would
be
at
least
a
factor
of
100
(20dB)

less
than
the
value
calculated
for
the
equivalent
distance
in
the
main
beam.

Near
Field
On-‐axis
power
density,

Wn

=
5.351
mW/cm^2

Near
Field
Off-‐axis
power
density,
2.4
meters
from
main
beam
center

Wn(off)

=
0.01
Wn

=
0.0535
mW/cm^2

Therefore,
the
area
around
and
behind
the
dish
at
a
distance
of
one
dish
diameter
(2.4

meters)
from
the
center
of
the
main
beam
will
be
equal
to
or
less
than
5.351
mW/cm^2.

For
off-‐axis
calculations
in
the
far-‐field,
the
calculated
main-‐beam
power
density
of
(Wf)

can
be
multiplied
by
the
appropriate
relative
power
density
factor
obtained
from
the

antenna
gain
pattern
to
obtain
a
more
realistic
estimate.

The
proposed
antenna
meets
or
exceeds
the
performance
specifications
under
part
25.209

of
the
FCC
rules.
The
off-‐axis
gain
of
this
antenna,
therefore,
is
equal
to
or
greater
than

10dBi
less
than
the
on-‐axis
gain
in
any
direction
of
48
degrees
or
more
removed
from
the

center
line
of
the
main
beam.

Far
Field
On-‐axis
power
density

Wf

=
2.2922
mW/cm^2

Far
Field
Off-‐axis
power
density

Wf(off)

=
.1
Wf

=
0.2292
mW/cm^2

Exhibit
No.
WVU
1

VII.

Summary
of
Expected
Radiation
Levels

Calculated
Maximum

Radiation
Level

Region

(mW/cm^2)

Hazard
Assessment

Far
Field
Region:

=
164.16
meters

2.2922

Potential
Hazard

Near
Field
Region:

=
68.4
meters

5.351

Potential
Hazard

Transition
Region:

5.351

Potential
Hazard

Reflector
Surface
Region:

8.8419

Potential
Hazard

Far
Field
off-‐axis
Region:

0.2292

Satisfies
ANSI

Near
Field
off-‐axis
Region:

0.0535

Satisfies
ANSI

Area
around
dish
equal
to
dish
diameter:

0.0535

Satisfies
ANSI

VIII.
Conclusions

Based
on
the
above
analysis
it
is
concluded
that
the
ANSI
standards
of
5
mW/cm^2
or

greater
would
not
exist
in
regions
normally
occupied
by
the
public
or
the
earth
station=s

operating
personnel.

In
the
area
of
the
Main
Reflector,
personnel
would
only
enter
that
area
to
perform

maintenance
functions
and
the
transmitter
would
not
be
operational
at
that
time,
so
the

ANSI
standard
of
5
mW/cm^2
would
be
met.

In
the
area
of
the
Near
Field
and
Transition
Region,
since
the
antenna
is
mounted
at
a

height
of
2.7
meters
above
the
ground,
and
will
not
be
pointed
in
the
direction
of
populated

areas,
the
ANSI
standards
would
again
be
met.
Warning
signs
are
attached
to
the
surrounding

fence
to
warn
individuals
of
the
potential
for
hazardous
radiation.

In
addition,
the
transmit
power
used
in
these
calculations
is
greater
than
that
which
will

typically
be
utilized
by
the
earth
station.
During
normal
operation,
the
typical
power

level
would
generally
not
be
more
than
50
watts.
A
transmit
power
of
100
watts
would

only
occur
in
conditions
of
extreme
rain
fade.

Document Created: 2011-12-19 13:42:51
Document Modified: 2011-12-19 13:42:51

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