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EN50360/1

EN50360/1. Measurement of SAR related to human exposure to EM fields from mobile phones (300 MHz - 3 GHz) Group 4A member: Eric(92850219) Sam(50255035) Wilbur (97070763). Celluar phone Health concern. Brain cancer? Affect memory?

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EN50360/1

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  1. EN50360/1 Measurement of SAR related to human exposure to EM fields from mobile phones (300 MHz - 3 GHz) Group 4A member: Eric(92850219) Sam(50255035) Wilbur (97070763)

  2. Celluar phoneHealth concern • Brain cancer? • Affect memory? • Affect human analysis ability?

  3. Motorola SAM Scan Profiler in Hong Kong

  4. What is SAR?? • SAR - Specific Absorption Rate • It is an indication of the amount of radiation that is absorbed into a head whilst using a cellular phone • A SAR value is a measure of the maximum energy absorbed by a unit of mass of exposed tissue. • Units = watts per kilogram (W/kg)

  5. Definition of SAR • Definition of SAR: • Ei : rms value of the electric field strength in the tissue in V/m • σ : Conductivity of body tissue in Kg/m3 • Ci : heat capacity of body tissue in J/Kg K • : derivative of temperature in body tissue in K/s

  6. Preparation - Laboratory • 15˚c - 30˚c ±2˚c • No interact with local network • Be aware of ambient EM sources • Be aware of reflection from environment • Validation • At least once a year

  7. Preparation - Mobile • battery must be Fully charged • So that, the worst case (maximum power) obtained • At least 50cm between emulator antenna and the mobile • 1‰ or less power from the antenna with respect to the mobile

  8. GPIB to grab the data from the DVM Position Controller Serial Ports: COM1, COM2, COM3 3 channels DVM with DAQ card x y z Amplifier Indication Board Right head Flat phantom Left head Hardware System Overview Change 2x9V batteries every 16 hours

  9. Tests to be performed • Cheek and tilted • Left and right sides of the head • Center frequency of each band • Retractable antenna • Extended • Retracted • Multi-mode/multi-band • Performed in each mode with max power

  10. Test Setup • Mobile phone operating at the maximum power level • Phone holder described positions at a shell phantom of a human being

  11. Test Setup • Probes with high sensitivity and low field disturbance are used • Move along X-axis, Y-axis, Z-axis

  12. Test setup • Electric field strength E is measured in the tissue simulating liquid • Tissue simulation liquid: • Dielectric properties • 900MHz: 64.81% 1,2-propanediol; 34.4% de-ionized water; 0.79 NaCl salt

  13. Phantom Requirements • The phantom is a simplified representation of the human anatomy and comprised of material with electrical properties similar to the corresponding tissues. The physical characteristics of the phantom model shall resemble the head and the neck of a user since the shape is a dominant parameter for exposure.

  14. Phantom Requirements • Shape is a dominant parameter for exposure. • 90% large adult male study by anthropomorphic study in 1989 • Fill with tissue simulating liquid through head to neck

  15. Test Setup

  16. Handset vertical and horizontal reference lines.

  17. Phantom reference points.

  18. Cheek Position

  19. Tilted position

  20. Validation • Simplified performance checking • Phantom setup • Dipole source • Dipole input power measurement • System check procedure • System validation • known SAR values of selected mobile

  21. Test Setup

  22. Validation Test installation (Use flat phantom) Flat Phantom For SAM Profiler, 250mW output will give 2.5mW/g. 11mm 250mW=24dBm Directional Coupler Amplifier Signal Generator Checked the reflected power

  23. SAM Profiler is used to control the Scan Profiler.The interface is shown below:

  24. Result

  25. Definition of SAR • Definition of SAR: • Ei : rms value of the electric field strength in the tissue in V/m • σ : Conductivity of body tissue in Kg/m3 • Ci : heat capacity of body tissue in J/Kg K • : derivative of temperature in body tissue in K/s

  26. QuantizationHaving in mind a worst case consideration, the SAR limit is valid for uncontrolled environment mobile respectively portable transmitters.

  27. The SAR values of your mobile phone may be found from the following website www.SARvalues.com

  28. SAR values of some models

  29. Future Development • Whole body measurement

  30. Thanks for attention

  31. Q & A

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