On-body Antenna Design using Carbon Nanotubes Presenter : Syed Muzahir Abbas, Ph.D. Student Supervisor : Prof. Karu Esselle Centre for Electromagnetic and Antenna Engineering (CELANE) Department of Engineering 1/28
Presentation Outline • Project Overview • Background – Antennas – CNT – CNT Yarns – Body Centric Communication – On-body Antennas • Research Objectives – On-body Antenna Design Requirements – Design Constraints/Aims & Objective – Expected Outcomes • Task Plan • Conclusion 2/28
Project Overview 3/28
Presentation Outline • Project Overview • Background – Antennas – CNT – CNT Yarns – Body Centric Communication – On-body Antennas • Research Objectives – On-body Antenna Design Requirements – Design Constraints/Aims & Objective – Expected Outcomes • Task Plan • Conclusion 4/28
Antennas [1] • Antenna Definition “Usually a metallic device (as a rod or wire) for radiating or receiving radio waves”. (Webster’s dictionary) OR “A means for radiating or receiving radio waves”. (IEEE Standard) • Antenna Parameters – Antenna Impendence – Efficiency – Radiation Pattern – Antenna Gain – Directivity – Antenna Polarization – Bandwidth – Return Loss [1] C. A. Balanis, Antenna Theory: Analysis and Design: John Wiley, 2005. 5/28
Carbon Nanotube (CNT) • Potential candidates for replacement of conventional metals – Density of CNT composites is about five time lower than copper and around half that of aluminium. – Thermal conductivity is about ten times that of copper • Significant Advantages – Mechanical (high strength and load bearing) Fig. 1: Diamond * – Electrical (conductivity and resistivity) – Thermal (sustain at high temperatures) Graphene – Non-oxidizing abilities • Applications – Nanoantennas – Nanoelectronics • Allotropes of carbon with a cylindrical nanostructure Fig. 2: Graphite * * http://chem-guide.blogspot.com.au/2010/04/covalent-solid.html 6/28
Carbon Nanotube (CNT) -- Continued • CNT can be categorized as – Single-Walled Carbon Nanotube (SWCNT) A layer of graphite, a single atom thick, called graphene, which is rolled into a seamless cylinder Diameter is close to 1nm Length thousand times of diameter Fig. 3: SWCNT * – Multi-Walled Carbon Nanotube (MWCNT) Consist of concentric tubes (i.e. multiple rolled layers) of graphene. OR As a single sheet of graphite rolled into the shape of a scroll. Diameter range is 5nm to 50nm Length thousand times of diameter Fig. 4: MWCNT * *http://staff.aist.go.jp/h-kataura/Kogaku-kiji-forweb.htm 7/28
Carbon Nanotube (CNT) -- Continued a b c d Fig. 5: Carbon Nanotubes * * http://explow.com/buckypaper 8/28 http://www.phy.mtu.edu/yap/frontiercarbon.html
CNTs in Antenna Applications -- Continued • Load Bearing Antenna Applications [2] – Polymer-carbon nanotube sheets for conformal load bearing antennas. – Presented circuit model to calculate CNT sheet conductivity. – Presented fabrication process. Fig. 6: Circuit model for conductivity [2] 9/28
CNTs in Antenna Applications -- Continued – Conducted mechanical tests for • Stress, • Strain • Bending (a) Fig. 7: (a) Stress (b) Strain (c) Bend [2] (b) – Proposed it suitable for conformal load bearing antennas and RF circuits. [2] Z. Yijun, Y. Bayram, D. Feng, D. Liming, and J. L. Volakis, "Polymer-Carbon Nanotube Sheets for Conformal Load Bearing Antennas," Antennas and Propagation, IEEE Transactions on, vol. 58, pp. 2169-2175, 2010. (c) 10/28
CNTs in Antenna Applications -- Continued • Multiband Wireless Applications [3] – Full-Composite Fractal Antenna Using Carbon Nanotubes for Multiband Wireless Applications. – UHF-RFID (900MHz), Blutooth (2.4GHz) and WLAN (5.5GHz). – Presented antenna design and fabrication process. – Antenna gain and read range can be controlled by changing the conductivity of composite, which is not possible for materials with fixed conductivity such as copper. Fig. 8: Fractal Antenna Design [3] [3] A. Mehdipour, I. D. Rosca, A. R. Sebak, C. W. Trueman, and S. V. Hoa, "Full-Composite Fractal Antenna Using Carbon Nanotubes for Multiband Wireless Applications," Antennas and Wireless Propagation Letters, IEEE, vol. 9, pp. 891-894, 2010. 11/28
CNTs in Antenna Applications -- Continued • Wideband Millimeter-Wave Antenna Applications [4] – Comparison of copper and CNT antennas. – Frequency range 24 - 34 GHz. – Presented antenna design and fabrication process. – Housing effect on the performance of CNT antenna is much lower than for the copper (a) antenna – Above 30GHz its significantly less resulting in stable gain and less distortion in radiation pattern. [4] A. Mehdipour, I. D. Rosca, A. R. Sebak, C. W. Trueman, and S. V. Hoa, "Carbon Nanotube Composites for Wideband Millimeter- Wave Antenna Applications," Antennas and Propagation, IEEE Transactions on, vol. 59, pp. 3572-3578, 2011. (b) Fig. 9: (a) Antenna Design (b) Array [4] 12/28
Carbon Nanotube (CNT) Yarns • CNT yarns (fibers) are composed of individual CNTs • Can be spun from CNT forest by spinning • By passing CNT films through a drop of volatile liquid Fig. 10: CNT yarns production by CSIRO* * http://www.csiro.au/Outcomes/Materials-and-Manufacturing/ 13/28 Innovation/Carbon-Nanotubes-2.aspx
Body Centric Communication [5] • Off-body communication – Communications from off-body to an on-body device or system • On-body communication – Communications within on-body networks and wearable systems • In-body communication – Communications to medical implants and sensor networks Fig. 11: Human body model 14/28
Presentation Outline • Project Overview • Background – Antennas – CNT – CNT Yarns – Body Centric Communication – On-body Antennas • Research Objectives – On-body Antenna Design Requirements – Design Constraints/Aims & Objective – Expected Outcomes • Task Plan • Conclusion 15/28
On-body Antenna Design Requirements • Frequency Range – UWB lower band (3 - 5 GHz) – UWB (3.1 – 10.6 GHz) – V-Band (7 GHz around 60 GHz) TABLE: Unlicensed frequency bands around 60 GHz [6]. Country Japan USA Canada Korea Europe Australia Frequency Band (GHz) 59-66 57.05-64 57-64 57-64 57-64 59.4-62 • Antenna Impedance – 50 ohm 16/28
Design Constraints/Aims & Objective • Polarization – Horizontal / Vertical • Radiation Pattern [6] – Omni-directional and along the body surface • Full Ground Plane – To prevent radiation towards body • Bandwidth – Larger bandwidth • Size/Weight – Small/Light • Distance b/w antenna and body 17/28
Expected Outcomes • RF/Microwave characterization of CNT yarns • Antenna prototype for on-body communication with desired parameters • Which polarization is suitable and why? • Desired radiation pattern over the required bandwidth • How bandwidth can be enhanced in presence of full ground plane? • Recommended distance between antenna and body? 18/28
Presentation Outline • Project Overview • Background – Antennas – CNT – CNT Yarns – Body Centric Communication – On-body Antennas • Research Objectives – On-body Antenna Design Requirements – Design Constraints/Aims & Objective – Expected Outcomes • Task Plan • Conclusion 19/28
Task Plan-First year (2012-2013) Months 1 - 6 7 - 8 9 - 11 12 Task-1, Literature Review Mar – Aug2012 Task-2, Software Learning Sep-Oct Task-3, Test Structures Designing Nov-Jan2013 Task-4, Test Structures Fabrication Feb Task-1, Literature Review (6-months) – To strengthen the relevant knowledge and to gain detailed insight of existing work carried out so far in the field under investigation – CNT, CNT yarns, Antennas, On-body communication/antennas, UWB, Human body properties Deliverables – Literature review report 20/28
Task Plan-First year (2012-2013) Task-1, Achieved (March 2012 to date) – CNT, CNT yarns, Antennas, On-body communication/antennas, UWB, Human body properties Task-2, Software Learning (2-months) – High Frequency Structure Simulator (HFSS) Completed – CST Microwave Studio In progress – AWR Microwave Office In progress Tasks To Do – Task-3, Test Structures Designing – Task-4, Test Structures Fabrication Deliverables – Test Structures 21/28
Task Plan-Second year (2013-2014) Months 13 - 15 16 - 18 19 - 21 22-24 Mar – May2013 Task-5, CNT Measurements Jun-Aug Task-6, Antenna Designing Sep-Nov Task-7, Antenna Simulations Dec Task-8, Antenna Fabrication Jan-Feb2014 Task-9, Antenna Testing Deliverables – Properties of CNT yarns – Antenna prototype – Publication of results in International conferences/journals 22/28
Task Plan-Third year (2014-2015) Months 25 - 26 27 - 36 Task-10, Results and Analysis Mar-Apr2014 May2014 - Feb2015 Task-11, Write-up Deliverables – Publication of results in International conferences/journals – Thesis write-up – Completion of thesis in 3 years 23/28
Presentation Outline • Project Overview • Background – Antennas – CNT – CNT Yarns – Body Centric Communication – On-body Antennas • Research Objectives – On-body Antenna Design Requirements – Design Constraints/Aims & Objective – Expected Outcomes • Task Plan • Conclusion 24/28
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