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Compact UWB Wearable Antenna with Improved Bandwidth and Low SAR

Compact UWB Wearable Antenna with Improved Bandwidth and Low SAR. Authors WADHAH ABDO MOHAMMED AL-ASHWAL & DR KHAIRUN NIDZAM BIN RAMLI Presenter : WADHAH ABDO MOHAMMED AL-ASHWAL. 10/12/2013, 12:00PM . Outline. Introduction Overview Background Antenna design Antenna materials

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Compact UWB Wearable Antenna with Improved Bandwidth and Low SAR

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  1. Compact UWB Wearable Antenna with Improved Bandwidth and Low SAR Authors WADHAH ABDO MOHAMMED AL-ASHWAL & DR KHAIRUN NIDZAM BIN RAMLI Presenter : WADHAH ABDO MOHAMMED AL-ASHWAL 10/12/2013, 12:00PM

  2. Outline • Introduction • Overview • Background • Antenna design • Antenna materials • Antenna geometry • Results and discussions • Antenna performance at free space. • Antenna performance at the presence of the body • SPECIFIC ABSORPTION RATE (SAR) • Conclusion

  3. Introduction • Overview • ‘Ultra-wideband’ (UWB) commonly refers to signals or systems that have a large bandwidth. • In the past few years Ultra wideband (UWB) technology has received increasing attention in the communication system. • Its main advantages over (narrowband) wireless communications systems are: low transmit power levels, high-data rates, and possibly simpler hardware configurations

  4. Wireless Communication System -41.3 dBm/MHz maximum power level for UWB

  5. Examples for existing communication standard • GPS (1.57–1.58 GHz) • WCDMA (1.92–2.17 GHz) • Bluetooth (2.4-2.48GHz) • WLAN 802.11b/g (5.15-5.825) • WLAN802.11b/g (2.4-2.4835) • Wi-max (3.3-3.6GHz) • Commercial UWB (3.1–10.6 GHz) • Vehicle UWB radar system(22-29GHz)

  6. Background • UWB technology has been employed for military sector communication systems for decades • Opening the unlicensed spectrum of UWB (3.1GHz – 10.6GHz) for commercial use has brought us variety of systems (indoor applications) • Recently, wearable applications have combined miniaturization of electronic devices. • Therefore, a growing interest exists for wearable antennas and electronics. • All for flexibility and portability. • Integrating UWB wearable systems and textile technology

  7. Background • Body-worn antennas systems embedded into the so-called “smart clothes” • Merging between wearable systems, (UWB) technology and textile technology. • Such flexible antennas can be easily integrated into a piece of clothing. • Why textiles? Medical Body Area Networks (MBAN)

  8. Background • attention to the impact of the interaction between electromagnetic (EM) fields and the human body. • Therefore, Specific Absorption Rate (SAR) is required.

  9. ANTENNA DESIGN • Antenna Materials • (jeans) • metallic radiator (adhesive copper tape) • ɛr and loss tangent have been averaged to 1.76, 0.078 respectively.

  10. ANTENNA DESIGN • Antenna Geometry • rectangular patch • slot and truncation techniques in order to enhance the bandwidth. • ground plane truncated and notched • Substrate: L × W (46 × 46 mm2), • Patch :l × w (25 × 21.6 mm2), r = 4 mm, Sl × Sw (2 × 11 mm2), lf = 18 mm and wf = 3.64 mm • Ground: lg × W (13.8 × 46 mm2), ln × wn (8 × 2.6 mm2).

  11. RESULTS AND DISCUSSIONS • Simulated S11 • 2.25 GHz and 12.19 GHz • Abs BW = 9.94 GHz • Fractional BW %= 137% • measured S11 • 3.04 GHz-10.3 GHz • Abs BW = 7.26 GHz • Fractional BW %= 108%

  12. RESULTS AND DISCUSSIONS • 2D radiation pattern

  13. ANTENNA PERFORMANCE AT THE PRESENCE OF THE BODY • Four-layer model (skin, fat, muscle and bone) has been considered for the evaluation, (Curvature approximated to conical shape ). • skin = 2 mm, fat = 3 mm, muscle = 8 mm and bone = 10 mm (radius). • Body Tissue Dielectric Parameters Tool provided by FCC official website • Antenna placed at 1.5 mm from the origin.

  14. ANTENNA PERFORMANCE AT THE PRESENCE OF THE BODY • Simulated results: • Operating frequency: 4.2 GHz-10.6 GHz • Fractional BW can reach up to 86.48%. • skin = 2 mm, fat = 3 mm, muscle = 8 mm and bone = 10 mm (radius) Substrate: jeans. • Body Tissue Dielectric Parameters Tool provided by FCC official website • Antenna placed at 1.5 mm from the origin.

  15. ANTENNA PERFORMANCE AT THE PRESENCE OF THE BODY

  16. SPECIFIC ABSORPTION RATE (SAR) • evaluation of the power absorbed by the human body, (power absorbed per unit mass) W/kg . • Phantoms • By homogenous (rectangles) • homogenous and layered body model (layered Rectangles) • Voxel • Full or partial?

  17. (SAR) • peak 10-g SAR for the body model • contrast difference of the dielectric constant between skin and fat layers • different internal structure gives different distribution of the penetrating radiation • The skin has the highest conductivity followed by muscle and bone layers, while the fat has the lowest. 10 g averaging limit = 4 W/kg

  18. Conclusion

  19. THANK YOU

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