Attachment Radiation Analysis.p

This document pretains to SES-LIC-20110209-00130 for License on a Satellite Earth Station filing.

IBFS_SESLIC2011020900130_867977

Radiation Analysis Analysis of Non-ionizing Radiation For General Dynamics 2.40 Meter Antenna This report analyzes the non-ioninizing radiation levels for an earth station using the VertexRSI antenna. The equations used in these calculations are presented in the Office of Science and Technology Bulletin No. 65, Oct. 1985 as revised in 1997 in Edition 97-01. The purpose of this analysis is to determine the power flux densities in the far field, near field, transition region, between the sub- and main-reflector surface, and between the antenna edges and ground. Per FCC R&O 96- 326, the maximum level of non-ionizing radiation is limited to a power density of 5 milliwatts per square centimeter over any 6 minute in a controlled environment. The maximum level of non-ionizing radiation is limited to a power density of 1 milliwatt per square centimeter over any 30 minutes in a uncontrolled environment. Antenna Diameter 235 cm Antenna Aperture Area 43355 cm2 Subreflector Diameter 51 cm Area of Subreflector 2027 cm2 Frequency 13.75 GHz Wavelength 2.18 cm Total Transmit Power at Flange 100 Watts Antenna Gain 48.50 dB Antenna Aperture Efficiency 61.8% Height of Object to be cleared by main beam 3 m Far Field Calculations Distance to the beginning of far field 15191 cm 2 On axis power density in the far field 2.44 mW/cm Near Field Calculations Distance to the end of near field 6330 cm 2 Near Field Power Density 5.70 mW/cm Controlled Environment: Non-Compliant with FCC Limits Uncontrolled Environment: Non-Compliant with FCC Limits Transition Region Calculation The transition region is located between the near and far field regions. As stated above, the power density begins to decrease with distance in the transition region. While the power density decreases inversely with distance in the transition region, the power density decreases inversely with the square of the distance in the far field region. The maximum power density in the transition region will not exceed that calculated for the near field region. 2/8/2011 Page 1 of 2

Radiation Analysis Region between Main Reflector and Subreflector Transmissions from the feed horn are directed toward the subreflector surface, and are reflected back toward the main reflector. The energy density between the subreflector and main reflector surfaces can be calculated by determining the power density at the subreflector surface. 2 Power density at subreflector edge 98.68 mW/cm Main Reflector Region The power density in the main reflector region is determined in the same manner as the power density in the subreflector above. 2 Power density at the main reflector edge 4.61 mW/cm Region between Main Reflector and Ground Assuming uniform illumination of the reflector surface, the power density between antenna and ground can be calculated as follows: 2 Power density between Reflector and Ground 2.31 mW/cm Controlled Environment: Compliant with FCC Limits Uncontrolled Environment: Non-Compliant with FCC Limits Safety region in front of Antenna Considering walking along the antenna boresight, the distances one has to obtain from the antenna to achieve safe power density levels are, respectively, Controlled Environment; distance on-axis 106.15 m Uncontrolled Environment; distance on-axis 237.35 m Similarly, when a path is followed parallel to the antenna's boresight axis yet removed from the center axis by a distance equal to the antenna diameter, the power density is reduced by at least 20 dB (per Bulletin 65). The safety region in front of the antenna is finally defined by the following distance from a vertical axis through the antenna center as Elevation Angle Minimum distance 5 36.4 m 10 18.2 m 20 9.1 m 30 6.1 m 40 4.6 m 2/8/2011 Page 2 of 2


Document Created: 2019-04-20 20:02:37
Document Modified: 2019-04-20 20:02:37
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