Flexible Antennas


Published on

Final term presentation made for advanced antenna theory course

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Flexible Antennas

  1. 1. Riaz Ahmed LiyakathDepartment of Electrical Engineering University of South Florida Tampa, FL-33620 1
  2. 2. PRESENTATION OVER-VIEW: Introduction to flexible electronics Why we go for flexible antennas? Materials used for making flexible antennas Examples to explain the working of various types of flexible antennas My current research Challenges and future scope 2
  3. 3. REASONS TO MAKE ANTENNAS FLEXIBLE: Flexible antennas are robust light weight antennas which are withstand mechanical strain upto a certain extent. Flexible antennas Polymer based Carbon nano- antennas tube antennas Fig 1. Scope of flexible electronics Textile antennas Micro fluidic antennas Fig 2. Antennas for air-crafts 3
  4. 4. MATERIALS USED FOR FLEXIBLE ANTENNAS: 1. Polymer based antennas: FABRICTION PROCESS:i) Silicone elastomers: Polydimethyl Siloxane (PDMS): Fig 1. Various silicone elastomers Reasons to opt for PDMS: PDMS an inexpensive, flexible polymer Can withstand mechanical strain Can be mixed and cured at room temperature Dielectric properties can be tuned. ii) PDMS- ceramic composites: Fig 2. Patch antenna made from PDMS- ceramic composite 4
  5. 5. 3. Compressed Nano tubes: Fig 1. CNT based antenna APPLICATIONS: High gain-beamforming antennas for wireless systems 4. Micro fluidics/ Liquid metals: Liquid metals are filled in micro-fluidic 5. Textiles: cavities in an silicone elastomer.  FlecTron The liquid metal prevents loss of electrical connectivity when the antenna fleece fabric is deformed. Conductive  Liquid metal antennas on the other textiles coated hand, can conform to any shape without with Carbon strain and can be reversibly deformed. nanotubes(CNTs) and goldFig 2. Twisted liquid metal antenna 5
  6. 6. LIQUID METAL PLANAR INVERTED CONE ANTENNA (PICA): The planar inverted cone antenna (PICA) operates in the Ultra wide band (UWB) of frequency 3.1 to 10.6 GHz Fig. 2: Feed cable Fig. 1: Sketch of feed cable Fig. 3: Return loss and efficiency connection to the antennaThe antenna is manufactured byinjecting liquid metal into micro-structured channels in the elasticPDMS material. The antenna has a good return lossof 10 dB in the operating frequencyand the radiation efficiency was alsoobserved to be greater than 70%which is considered good. Fig. 3: Photographs of the stretchable PICA: (a) and (c)The produced antenna allows non-stretched antenna, (b) stretched antenna with 40%stretching up to 40%. y-axis elongation, (d) stretched antenna with 40% -axis elongation, (e) folded antenna, and (f) twisted antenna.It is a highly broadband antenna Shi Cheng, Zhigang Wu, Paul Hallbjörner, Klas Hjort, Anders Rydberg, “Foldable and Stretchable Liquid Metal Planar Inverted Cone Antenna”, IEEE Transactions on Antennas and Propogation, Vol. 57, No. 12, Dec 2009 6
  7. 7. REVERSIBLY DEFORMABLE AND MECHANICALLY TUNABLE FLUIDIC ANTENNAS :The antenna consist of a fluid metal alloy ( eutectic Fabrication Process:gallium indium - EGaIn) injected into micro fluidicchannels comprising a silicone elastomer (PDMS). FLUIDIC DIPOLE FEATURES:  Withstand mechanical deformation (stretching, bending, rolling, and twisting) Resonant frequency can be tuned mechanically by elongating the antenna Resonates at 1962 MHz Efficiency is around 90%(approx.) at a broad Fig,.3: Measured reflection coefficient of the dipole both in frequency range (1910–1990 MHz) its ‘‘relaxed’’ position (54mm length) and mechanically The size of antenna is 54 mm elongated positions (58, 62, and 66mm length) as a function of frequency. The ability to stretch the antenna allows the Simple to fabricate frequency to be tuned mechanically. Fig 1. prototype antenna being stretched Figure 4. Resonance frequency of a fluidic dipole antenna as a function of the length of the antenna as modulated by stretching Ju-Hee So, Jacob Thelen, Amit Qusba, Gerard J. Hayes, Gianluca Lazzi, and Michael D. Dickey, „Reversibly Deformable and Mechanically Tunable FluidicFig 2. prototype antenna being rolled (left) and antenna Antennas‟ , Adv. Funct. Mater. 2009, 19, 3632–3637 7self-heals in response to sharp cuts
  8. 8. ELASTIC ANTENNAS BY METALLISED ELASTOMERS: Fig 4. Radiation patterns Fig 3. Ultra-wideband monopole antenna The objective of this is to investigate Elastic antennas made by metallised elastomers at RF frequencies for microwave transmission lines and antennas applications Fig 1: Elastic coplanar waveguide: Fig 5: Simulated return loss of Fig 2: Normal coplanar waveguide: ultra-wideband antennas Both give radiation patterns as expected for a normal monopole antenna 8
  9. 9. Table 1: Conductor thickness vs. Efficiency Fig.6 : Self-compensating antenna The below table shows that the conductor thickness is important for designing an efficient antenna Fig 7: Simulated return loss after stretching Qing Liu, Kenneth Lee Ford, Richard Langley,”Elastic Antennas by Metallised Elastomers”, 2010 Loughborough Antennas & Propagation Conference, Nov 2010 9
  10. 10. A MILLIMETER-WAVE MICROSTRIP ANTENNA ARRAY ON ULTRA-FLEXIBLEMICRO MACHINED POLYDIMETHYLSILOXANE (PDMS) POLYMER:  As bulk PDMS is demonstrated to be lossy at millimeter waves, membrane-supported devices are considered. Antenna array  A new reliable and robust technological process has been Fig. 2. (a) Layout of the developed to micro machine membrane-supported A 4 X 2-element transmission lines and microstrip antenna arrays. microstrip antenna array supported by a PDMS microstrip antenna array Transmission lines membrane supported by a 20- and zoom to see rounded micro meter-thick The insertion loss of microstrip lines angles. (b) 3-D schematic PDMS membrane is fabricated on 20- m-thick membranes is of the designed. about 0.5 dB/cm at 60 GHz. antenna array. (c) Photograph of the fabricated prototype Fig. 3(below). Measured and computed radiation patterns of the membrane supported microstrip antenna array at 55 GHz. (a) H-plane. (b) E-planeFig. 1. (a) Schematic view of 50- ohm transmission lines printed on bulkPDMS and PDMS membranes . (b) Bulk PDMS transmission line in the Sami Hage-Ali, Nicolas Tiercelin, Philippe Coquet, Ronanimpedance measurement setup based on an Anritsu Universal test fixture 3680 Fig. 3. (a) Reflection coefficient Sauleau, Hiroyuki Fujita, Vladimir Preobrazhensky, and Philippe Pernodm,‟ A Millimeter-Wave Microstrip Antenna Array on Ultra-V. (c) 50-ohm transmission line on a PDMS membrane d) Measured and and (b) input impedance of the Flexible Micromachined Polydimethylsiloxane (PDMS) Polymer‟computed insertion loss of 50-ohm transmission lines printed on bulk PDMS antenna array. , IEEE ANTENNAS AND WIRELESS PROPAGATION 10and 20-m-thick PDMS membranes LETTERS, VOL. 8, 2009
  11. 11. DESIGN AND MANUFACTURING OF STRETCHABLE HIGH-FREQUENCY INTERCONNECTS: Meander-shaped conductors in a coplanar waveguide topology. They are produced based on laser-ablation of a copper foil, which is then embedded in a highly stretchable bio-compatible Fig. 1 Structure of the entire silicone material - Silastic external interconnection MDX4-4210 . Fig. 2 Comparative simulation of the magnitude of the reflection coefficient of a straight and horseshoe-shaped CPW Fig. 5 Tapered interconnection between the pads and the CPW Maximal magnitude of -14 dB Fig 3. Horse-shaped CPW for the reflection coefficient and a minimal magnitude of -4 dB for the transmission coefficient in the frequency band up to 3 GHz. Neither magnitude nor the phase of the transmission coefficient was influenced by elongations up to 20%.Fig 4. Structure of the flexible Fig. 6 Close up of the horseshoe-shaped CPWlink Fig. 5 Close up of the horseshoe-shaped CPW 11 Fig. 7 Prototype stretchable high-frequency interconnect
  12. 12. ROBUST PLANAR TEXTILE ANTENNA FOR WIRELESS BODY LANSOPERATING IN 2.45 GHZ ISM BAND:A single-feed rectangular-ring textileantenna is proposed for wireless bodyarea networks operating in the 2.45GHz ISM band.Conductive part - FlecTronNon-conductive antenna substrate -fleece fabric Fig. 2 Measured and simulated return loss (S11) Fig. 3 Measured antenna gain along broadside Fig. 4 Simulated antenna gain at 2.45 GHz a xz-plane b yz-plane ADVANATGES: Highly efficient Flexible Wearable A. Tronquo, H. Rogier, C. Hertleer and L. Van Langenhove, „Robust planar textile antenna for wireless body LANs operating in 2.45 GHzFig. 1 Geometry of rectangular-ring microstrip textile antenna ISM band‟ , ELECTRONICS LETTERS 2nd February 2006 . 12
  13. 13. DUAL-BAND TEXTILE ANTENNA USING AN EBG STRUCTURE: Antenna on EBG geometryThe antenna is fully characterized in free space and on the body model, with and without an electromagnetic band gap (EBG) substrate. The bandgap array consists of 3 3 elements and is used to reduce the interaction with human tissues. With the EBG back reflector, the radiation into the body is reduced by more than 15 dB.Increases of 5.2 dB and 3 dB gain are noticed at 2.45 GHz and 5.5 GHz, respectively. Dual-band coplanar antenna. The efficiency of the antenna combined with the EBG structure and placed 1 mm above the homogeneous phantom, significantly increases (83% at 2.45 GHz and 86% at 5.5 GHz). EBG geometry Nacer Chahat1, Maxim Zhadobov, Ronan Sauleau, Kouroch Mahdjoubi, „Improvement of the On-Body Performance of a Dual-Band Textile Antenna Using an EBG structure ‟, 2010 Loughborough Antennas & Propagation Conference 13
  14. 14. A FLEXIBLE MONOPOLE ANTENNA WITH BAND-NOTCH FUNCTION FORUWB SYSTEMS: Fig 1. Rolled type flexible antenna  A flexible monopole antenna for UWB systems which can cover the frequency band 3.1 - 10.6 GHz is proposed and fabricated on PET film having the flexible characteristic.  To obtain the wide bandwidth, the stepped CPW feed line and the declined shape of the ground plane is used.  It has a band-notch function of 5 GHz WLAN band using two slits. Thisis used to reject 5 GHz band, which includes the limited band by IEEE802. 1 la and HIPERLAN/2. Fig 2. Rolled type flexible antenna Fig 3. The parameter study of Su Won Bae, Hyung Kuk Yoon, Woo Suk Kang, Young Joong Yoon and Cheon-Hee Lee, the length of the slit of the „A Flexible Monopole Antenna with Band-notch Function for UWB Systems‟ , Proceedings of flexible UWB antenna Asia-Pacific Microwave Conference 2007 14
  15. 15. OPTICALLY TRANSPARENT ULTRA-WIDEBAND ANTENNA: Optically transparent ultra-wideband (UWB) disc monopole using AgHT-4 transparent film is designed. The antenna is fed by a 50 V coplanar waveguide Its operational bandwidth is measured from 1 to 8.5 GHz. Fig. 1 UWB transparent antenna Fig. 2 Measured and simulated return loss Fig. 3 Gain sweep for transparent and aluminum UWB antenna using coaxial and optical fibreFig. 4 H (left) and E-plane radiation patterns for transparent and aluminium UWB APPLICATIONS: Vehicles, Building windows, Computer video monitors Solar photovoltaic panels A. Katsounaros, Y. Hao, N. Collings and W.A. Crossland, „Optically transparent ultra-wideband antenna‟, ELECTRONICS LETTERS 2nd July 2009 Vol. 45 No. 14 15
  16. 16. MY RESEARCH:We plan to make a planar antenna on a flexible substrate that can be tuned to work over a range of frequencies bystretching the substrate. STRETCH ALONG LENGTH: 5% stretch S11 0 -5 Mag. [dB] m1 -10 f req=2.427GHz dB(new stlen5per_mom_a..S(1,1))=-23.646 -15 Min -20 m1 -25 25% stretch 1.0 1.5 2.0 2.5 3.0 Frequency 3.5 4.0 4.5 5.0 m1 S11 freq=2.057GHz 0 dB(newstlen25per_mom_a..S(1,1))=-31.789 Fig 1.Fundamental idea Min -10 Mag. [dB] -20 -30 m1 -40 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Frequency STRETCH ALONG WIDTH: 10% stretch 0 S11 m1 freq=2.537GHz -10 dB(newstwid5per_mom_a..S(1,1))=-41.608 Min Mag. [dB] -20 -30 m1 Fig 2. 4-probe measurement -40 Set-up (left) and fabricated -50 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 PDMS film (right) Frequency 16
  17. 17. WHAT FUTURE HOLDS FOR THESE ANTENNAS: E-Textiles MilitaryFlexible RFID tags Flexible antennas Medicine Air-planes 17
  18. 18. 18