Attachment Radiation Haz Study

This document pretains to SES-LIC-20071029-01471 for License on a Satellite Earth Station filing.

IBFS_SESLIC2007102901471_604398

Radiation Hazard Report ZSU-CERAP Page 1 of 9 Radiation Hazard Analysis San Juan (ZSU-CERAP) This report analyzes the non-ionizing radiation Ievels for a 4.5-meter earth station system. The analysis and calculations performed in this report comply with the methods described in the FCC Office of Engineering and Technology Bulletin No. 65 first published in 1985 and revised in 1997 in Edition 97-01. The radiation safety limits used in the analysis are in conformance with the FCC R&O 96-326, Bulletin No. 65 and the FCC R&O specifies that there are two separate tiers of exposures limits that are dependant on the situation in which the exposure takes place and/or the status of the individuals who are subject to the exposure. The Maximum Permissible Exposure (MPE) limits for persons in a General Population/Uncontrolled environment are shown in Table 1. The General Population/Uncontrolled MPE is a function of the transmit frequency and is for an exposure period of thirty minutes or less. The MPW limits for persons in an Occupational/Controlled environment are shown in Table 2. The Occupational MPE is a function of transmit frequency and is for an exposure period of six minutes or less. The purpose of the analysis described in this report is to determine the power flux density levels of the earth station in the far-field, near-field, transition region, between the subreflector or main reflector surface, at the main reflector surface, and between the antenna edge and the ground and to compare these levels to the specified MPEs. Table 1. Limits for General Population/Uncontrolled Exposure (MPE) Frequency Range (MHz) Power Density (mW/cm2) 30-300 0.2 300-1500 Frequency (MHz)*(0.8/1200) 1500-100,000 1.0 Table 2. Limits for Occupational/Controlled Exposure (MPE) Frequency Range (MHz) Power Density (mW/cm2) 30-300 1.0 300-1500 Frequency (MHz)*(4.0/1200) 1500-100,000 5.0 Table 3. Formulas and Parameters Used for Determining Power Flux Densities Parameter Symbol Formula Value Units Antenna Diameter D Input 4.5 m Antenna Surface Area Asurface πD2 / 4 15.90 m2 Subreflector Diameter Dsr Input N/A cm Area of Subreflector Asr πDsr 2 /4 N/A cm2 Frequency F Input 6000 MHz Wavelength λ 300 / F 0.05 m Transmit Power P Input 0.47 W Antenna Gain (dBi) Ges Input 42.05 dBi Antenna Gain (factor) G 10 Ges/10 16032.454 N/A Pi π Constant 3.1415927 N/A 2 2 2 Antenna Efficiency η Gλ /(π D ) 0.2005466 N/A

Radiation Hazard Report ZSU-CERAP Page 2 of 9 1. Far Field Radiation The distance to the beginning of the far field region can be expressed by the equation: Rff = 0.6 D2 R = Distance to beginning of far field (meters 0.60 m λ D = Antenna Diameter (meters) 4.50 m λ = Wavelength 0.05 m Rff = 0.60 x 4.50 x 4.50 = 243.00 meters 0.05 The maximum main beam power density in the far field can be determined from the following equation: Sff = GP G= Antenna Gain (factor) 16032.5 4 π Rff2 P= Transmit Power 0.47 W 2 2 Sff = 16,032.45 x 0.47 = 0.010155 W/m or 0.00102 mW/cm 4 x 3.1416 x 243 x 243

Radiation Hazard Report ZSU-CERAP Page 3 of 9 2. Near Field Radiation The extent of the near field can be described by the equation: WHERE: Rnf = D2 R = Extent of near-field meters 4λ D = Antenna diameter 4.5 meters λ = Wavelength 0.05 meters Rnf = 1.22 == 101.25 meters 4 x 0.0214 The maximum value of the near field on-axis (main beam) power density is given by the equation: Snf = 16 η P S = Maximum near-field power density 16 W/m 2 πD η = Efficiency of aperture (percentage) 0.200547 % P = Power into feed (Watts) 0.47 W D = Antenna Diameter (meters) 4.5 m Snf = 6 x 0.2005 x 0.47 = 0.0237 W/m or 0.00237 mW/cm2 3.1416 x 4.5 x 4.5

Radiation Hazard Report ZSU-CERAP Page 4 of 9 3. Transition Region On-axis power density will decrease with 40.37 meters distance in the transition region. The power density can be expressed by the equation: WHERE: St = Snf Rnf S = Power Density Rff Snf = Power Density in (near field) 0.002 mW/cm2 Rnf = Extent of near field 101.25 m Rff = Beginning of far field 243.00 m R = Distance to point of interest At the beginning of the transition region, i.e. at a distance of 101.25 meters, the power density equals: St = 0.002 x 101.25 = 0.00237 mW/cm2 101.25 At the beginning of the far-field region, i.e. at a distance of 243.00 meters, the power density equals: St = 0.002 x 101.25 = 0.00099 mW/cm2 243.00

Radiation Hazard Report ZSU-CERAP Page 5 of 9 4. Region between Main Reflector and Subreflector Transmissions from the feed assembly are directly toward the subreflector surface, and are reflected back toward the main reflector. The most common feed assemblies are waveguide flanges, horns or subreflectors. The energy between the subreflector and the reflector surfaces can be calculatee by determining the power density at the subreflector surface. This can be determined from the following equation: This antenna design does not incorporate a subreflector

Radiation Hazard Report ZSU-CERAP Page 6 of 9 5. Main Reflector Region The maximum power density between the main reflector and the feed is taken as the power density at the main reflector. This can be described from the equation: Ssurface = 4P P = Power into feed 0.47 W 2 Asurface Asurface = Reflector Surface Area 15.90 m Ssurface = 4 x 0.47 = 0.11821 W/m2 or 0.01182 mW/ cm2 15.90

Radiation Hazard Report ZSU-CERAP Page 7 of 9 6. Between Antenna and Ground Assuming uniform illumination of the reflector surface, the power density between the antenna and the ground can be determined from the following equation: Sg = P P = Power into feed 0.47 W 2 Asurface Asurface =Antenna Surface Area 15.90 m 2 2 Sg = 0.47 = 0.02955 W/m or 0.00296 mW/ cm 15.90

Radiation Hazard Report ZSU-CERAP Page 8 of 9 7. Summary of Calculations Table 4. Summary of Expected Rdiation Levels for Uncontrolled Environment Calculated Maximum Radiation Power Density Level Region (mW/cm2) Hazard Assessment 1. Far Field (Rff = 243 m) Sff 0.00102 Satisfies FCC MPE 2. Near Field (Rnf = 101.25 m) Snf 0.00237 Satisfies FCC MPE 3. Transition Region (Rnf < Rt < Rff) St 0.00237 Satisfies FCC MPE 4. Between Main Reflector and Ssr N/A No Subreflector Subreflector 5. Main Reflector Ssurface 0.01182 Satisfies FCC MPE 6. Between Main Reflector and Ground Sg 0.00296 Satisfies FCC MPE Table5. Summary of Expected Rdiation Levels for Controlled Environment Calculated Maximum Radiation Power Density Level Region (mW/cm2) Hazard Assessment 1. Far Field (Rff = m) Sff 0.00102 Satisfies FCC MPE 2. Near Field (Rnf = m) Snf 0.00237 Satisfies FCC MPE 3. Transition Region (Rnf < Rt < Rff) St 0.00237 Satisfies FCC MPE 4. Between Main Reflector and Ssr N/A No Subreflector Subreflector 5. Main Reflector Ssurface 0.01182 Satisfies FCC MPE 6. Between Main Reflector and Ground Sg 0.00296 Satisfies FCC MPE It is the applicant's responsibility to ensure that the public and operational personnel are not exposed to harmful levels of radiation.

Radiation Hazard Report ZSU-CERAP Page 9 of 9 8. Conclusions Bsed upon the above analysis, it is concluded that harmful levels of radiation will not exist within any region of this earth terminal.


Document Created: 2007-11-07 11:45:40
Document Modified: 2007-11-07 11:45:40
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