Rantec RadHaz

0359-EX-ST-2012 Text Documents

Intelsat License LLC

2012-05-02ELS_125269

Radiation Hazard Analysis
Rantec 18inch Ku Antenna

This exhibit presents the radiation hazard analysis for the Rantec 18inch Ku-band antenna to be
used in demonstration / validation testing. The analysis uses the procedure outlined in OET
Bulletin No. 65, Evaluating Compliance with FCC Guidelines for Human Exposure to Radio
Frequency Electromagnetic Fields, Edition 97-01, pp 26-30.

The maximum level of non-ionizing radiation to which employees may be exposed is limited to a
power density level of 5 milliwatts per square centimeter (5 mW/cm2) averaged over any 6
minute period in a controlled environment. The maximum level of non-ionizing radiation to
which the general public is exposed is limited to a power density level of 1 milliwatt per square
centimeter (1 mW/cm2) averaged over any 30 minute period in an uncontrolled environment.

Note that the worse-case radiation hazards exist along the beam axis. Under normal
circumstances, it is highly unlikely that the antenna beam axis will be aligned with an occupied
area since that would represent a blockage to the desired signals, thus rendering the link
unusable.

This analysis is done for exposure to radiation in the near field, the far field and the transition
region. Safe limits are computed for the controlled and uncontrolled exposure for both the
antenna main beam and sidelobes.

The near field region for the main beam is defined in terms of the radius Rnf according to the
relation
Rnf = D2/4λ
where D is the antenna diameter and λ is the transmit wavelength. Rnf, D and λ all have units of
cm, centimeters.

The maximum near field power density, Snf (units mW/cm2), is present at the face of the antenna
and is determined from
Snf = PPA/A
where PPA is the transmit power, in mW, (after cable losses are accounted for) and A is the
aperture of the antenna reflector, in cm2. For a parabolic reflector with a circular aperture such
as the Rantec 18inch, the surface area is A = pi * (D/2)2.

The far field region for the main beam is at any distance (R) away from the antenna greater than
Rff given by
Rff = 0.60 D2/λ

The far field power density Sff at distance R from the antenna is
Sff = PEIRP/4π R2
where R is ≥ Rff and PEIRP is the Effective Isotropic Radiated Power of the antenna. The
maximum far field power density is at R = Rff.

Near Field Exposure from Main Antenna Beam
The Rantec 18inch Ku antenna has D = 47.5 cm resulting in a surface area A = 1640 cm2. At a
transmit frequency of 14.5 GHz, the wavelength is 2.053 cm. The near field radius is then
Rnf = 254 cm (2.54 m).

The maximum permitted antenna radiation is 43.0 dBW. The antenna has a transmit gain of
34.47 dB. Consequently, the maximum transmit power is PPA = 8.53 dBW (=43 dBW-34.53 dB)
= 7.13 W = 7,129 mW. This results in a maximum near field power density of
Snf = 4.35 mW/cm2 at the surface of the antenna (= 7129 mW / 1640 cm2).

Far Field Exposure from Main Antenna Beam
The minimum far field radius is
Rff = 6.1 m.

The maximum far field power density is at the minimum far field radius, Rff. At the terminal’s
maximum transmit EIRP of 43.0 dBW, the far field power density at Rff is
Sff = 4.26 mW/cm2.

Meeting Radiation Exposure Limits

The 5 mW/cm2 power density for controlled exposure occurs at the surface of the antenna.

The 1 mW/cm2 power density for uncontrolled exposure occurs in the far field. At distance
R = 12.6 m, the far field power density is Sff = 1.00 mW/cm2.

Both of these distances are at beam peak and assume the terminal is transmitting at maximum
EIRP of 43.0 dBW.

Based on antenna sidelobes with 12 dB reduction from the main beam and using the far field
expressions, to meet the limit of
 5 mW/cm2 power density for less than 6 minutes for controlled exposure, no individual
shall be at the surface of the antenna while it is transmitting
 1 mW/cm2 power density for less than 30 minutes for uncontrolled exposure, no
individual shall be within 3.2 m of the antenna while it is transmitting.

Summary
This document presents the radiation hazard analysis for Rantec 18inch Ku antenna with a
maximum EIRP of 43.0 dBW. If individuals are in the main beam of the antenna
 for a controlled exposure, individuals shall be at least 0 meters away and for no more
than 6 minutes
 for an uncontrolled exposure, individuals shall be at least 12.6 meters away for no more
than 30 minutes.

Intelsat shall ensure that no individuals shall be within the above-referenced distances of the
antenna while it is transmitting. In particular, the antenna will be mounted to the top of an
airplane and Intelsat will control the area around the demonstration aircraft during stationary

operations to ensure that no individuals are within the main beam or sidelobes at the specified
distances. During in-motion operation, there is no possibility of human RF exposure since no
individuals will be within the specified distances of the moving aircraft. Backlobe roll-off and
attenuation from the antenna tracking system, mounting assembly and vehicle roof ensure that
individuals inside the aircraft will not be exposed to RF radiation in excess of permissible levels.

Document Created: 2012-05-02 13:48:36
Document Modified: 2012-05-02 13:48:36

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