Inkjet-Printable UHF RFID Tag Antenna on a ... - Semantic Scholar
Inkjet-Printable UHF RFID Tag Antenna on a Flexible CeramicPolymer Composite Substrate A. Ali Babar1, J. Virtanen1, V. A. Bhagavati2, L. Ukkonen1, A. Z. Elsherbeni3, P. Kallio2, and L. Sydänheimo1 1
Rauma Research Unit, Department of Electronics, Tampere University of Technology, Tampere, Finland Micro and Nano Systems Research Group, Department of Automation Science and Engineering, Tampere University of Technology, Tampere, Finland 3 Electrical Engineering Department, The University of Mississippi, University, MS 38677, USA.
2
Abstract — The utilization of inkjet-printing technique to develop a printable UHF RFID tag antenna on flexible ceramicpolymer composite material is demonstrated. The substrate material is fabricated using high permittivity Barium Titanate (BaTiO3) ceramic powder mixed with polydimethylsiloxane (PDMS) polymer. A UHF RFID tag antenna is inkjet-printed using silver nano-particle to exploit the potential advantages of high dielectric flexible composite material when used as a tag substrate. Our preliminary results yielded a small flexible UHF RFID tag antenna with read range comparable to commercially available tag antennas. Index Terms — Flexible Ceramics, Inkjet-printed Tag, RFID Technologies,
I. INTRODUCTION There has been a rapid progress in the field of wireless communications and identification in recent years. Effective and reliable tracking of various objects wirelessly, using radio frequency identification (RFID) technology, is gaining much attention. An RFID system is composed of two main components, the reader and the tag. A passive RFID tag is composed of an IC chip and an antenna. The IC of the tag antenna contains its own unique identification code (ID) [1]. This identification code is sent back to the reader when the tag is interrogated or energized through backscattered modulation of the incident continuous wave [2]. The UHF RFID tag antenna’s input impedance and reflectivity rely on the physical properties of the substrate or the material it is attached to and on the antenna geometry. The size of the tag antenna is greatly dependent on the permittivity of the substrate. Several types of substrates have been used and developed for electronic devices. Similarly, flexible substrates have also gained much importance in recent years [3], [4]. One of the most commonly used plastic substrates is polyester, PEEK (Polyaryletheretherketone) and polymides [5], [6]. There has been a growing interest in the development of flexible antennas. To achieve this, a more desirable approach is to use flexible substrate materials that are less vulnerable to heat, water and other damaging effects. In this paper, a high permittivity polymer-ceramic composite material is developed, for its possible use as a UHF RFID tag antenna substrate. Using substrates with high permittivity values helps in achieving smaller antenna designs.
A UHF RFID tag antenna is printed on top of the substrate using silver ink, with the help of an inkjet printer. The composite substrate is developed using a high permittivity ceramic powder with a polymer known as Polydimethylsiloxane (PDMS). This helps in achieving a soft, flexible, hydrophobic, low loss and heat resistant substrate material. The dielectric and physical properties of the composite material depend on the fabrication process, ratio and type of ceramic powder used. The permittivity values of the material can be changed by changing the amount of the ceramic powder in the composite. This provides the flexibility to achieve the desired high permittivity value of the substrate, and thus a small size tag antenna. Inkjet-printing using DMP-2800 inkjet-printer from FujiFilm Dimatix is chosen as the fabrication method as it allows rapid prototyping and non-contact fabrication of flexible conducting traces [7]. It can also be seen as a prominent fabrication method in the future of UHF RFID tags. Thus, this work also aims to demonstrate capability of inkjetprinting RFID tags on non-conventional substrate materials. II. CHARACTERISTIC OF THE COMPOSITE SUBSTRATE The ceramic-polymer composite substrate is developed by mixing Barium titanate (BaTiO3) ceramic powder with a polymer known as Polydimethylsiloxane. BaTiO3 is a ferroelectric ceramic, usually available in powder form, with piezoelectric properties [8]. It usually has high permittivity values [9]. However, the permittivity depends on several factors, such as grain size, shape and size of the crystals, impurities, and on other processing techniques [10]. These types of ferroelectric ceramics can be used in several electronic applications, such as multilayer capacitors [11], positive temperature coefficient (PTC) thermistors, transducers and tunable phase shifters [12]. Polydimethylsiloxane (PDMS) is a most widely used type of a silicon based organic polymer, belonging to a group of siloxanes. It is available in fluid, elastomer and resin form [9]. PDMS material has high thermal stability, low surface tension, and bulk viscosity. It is transparent in nature, durable at high temperatures, and hydrophobic. In elastomer form PDMS is suitable for flexible substrates. They are fabricated using
978-1-4673-1088-8/12/$31.00 ©2012 IEEE
viscous liquid and a liquid cross-linking agentt. The stiffness of the substrate depend on the amount of crooss-linking agent used, curing time and temperature. Theirr most common applications include rubber molds, surrfactants, water repellents, personal care and cosmeetics, dielectric encapsulation, contact lenses, medical aand microfluidic devices [13]. The substrate developed here is low loss, sooft and flexible in nature, resistant to water, heat, breaking andd other damaging effects. Desired permittivity values of the substrate can be achieved by changing the ratio of ceramic iin the composite substrate. This type of a substrate enables too achieve smaller tag antenna designs. (a) (b) Fig. 1. UHF RFID tag antenna (a) ( Geometrical parameters, (b) Printed on flexible ceramic-polymerr substrate.
III. SUBSTRATE FABRICATION PROCEEDURE The fabrication process of the ceramic-polyymer substrate is described in a stepwise approach. The PDMS used is Sylgard184, supplied with a two component kit coontaining a ‘base pre-polymer’ and a curing agent (crosss-linking agent) manufactured by Dow Corning [14]. The BaT TiO3 was supplied by Sachtleben Ltd. Following steps were useed to develop the composite substrate. A similar approach has aalso been studied in [15]. 1) The pre-polymer is mixed with the ccuring agent in a mass ratio of 10 (pre-polymer): 1(curinng agent). 2) Degassing is performed to remove th the excessive air bubbles formed during the mixing for 115-20min. 3) Then the PDMS is vigorously mixeed with BaTiO3 powder in a volume based ratio using eeq. (1).
%
⁄ ⁄
⁄
100%
(1)
In the above equation ‘ ’ and ‘ ’refer to the mass and density of the ceramic (BaTiO3), respectivelyy. Whereas, ‘ ’ and ‘ ’ are the mass and density of the polym mer (PDMS). 4) The smooth paste is left for degassing ffor 5-6 hours and kept under vacuum pressure for arouund 30 hours to remove most of the air bubbles from thhe mixture. IV. ANTENNA DESIGN A small symmetric dipole tag antenna design is printed on top of the composite substrate. The compoosite substrate is 1.5mm thick and has a dielectric constant cloose to 7. The tag antenna is designed using HFSS v.12. Alien H Higgs 3 IC with 18dBm sensitivity is attached between the tw wo feeding pads with dimensions ‘a’ and ‘b’. Figure 1 (a) shows the geometrical parameters of the UHF RFID ttag antenna. The dimensions of the tag antenna are listed in Table 1. The IC was connected directly to the printed tagg antenna using conductive epoxy glue.
TABLE I DIMENSIONS OF THE GEOMETRICAL L PARAMETERS OF THE TAG Line a b c d e f
Length (mm) 3.25 2.5 0.75 3.55 3.75 1
Width (mm) 2 2 -
Line g h k m n o
Length (mm) 14.5 4.15 6.75 7.5 16.6 26.5
Width (mm) 0.5 -
V. RESULT TS The following results demonstrate the possibility of developing inkjet-printed UHF RFIID tag on top of a ceramicpolymer composite substrate. Figu ure 1 (b) shows a recently designed a small UHF RFID tag which w is inkjet-printed with 4 layers of Harima NPS-JL silver nanoparticle ink having a 6 µ••cm specific resistance. particle size equal to 7 nm and 4-6 The optimal printing resolution wass found to be 847 dpi. First the tag is printed with 2 layers of silver s ink and sintered; this is followed by re-printing of 2 addiitional layers and sintering. The printed tag is sintered for 40 minutes m at a temperature of 170 Celsius. The performance of o the tag antenna can be further enhanced in the future by an nalyzing and improving the current technique. The RFID tag antenna is testeed for its read range and minimum threshold power required d to turn on the IC, in an anechoic chamber by Voyantic corrporations [16]. A linearly polarized reader antenna inside thee chamber is connected to the Tagformance measurement device to measure the performance of the RFID tag anten nna. The read range of the tag is calculated using the meeasured results from the Tagformance, using the following equation. e .
.
978-1-4673-1088-8/12/$31.00 ©2012 IEEE
(2)
In (2), ‘dtag’ represents the read range of the tag antenna. ‘Lfwd’ is the measured path loss from the geenerator’s output port to the input port of a hypothetical issotropic antenna placed at the tag’s location. The forward path loss is computed from the measured calibration data obtaained from the Tagformance measurement device. The Euuropean effective radiated power ‘PERP’ is considered to bee equal to 2W (33dBm). The parameter ‘Pth’ representss the measured threshold power in the forward direction, from m the transmitter to the tag antenna. The threshold power iis the minimum continuous wave power from the transmitter,, required to turn on the IC and enable the tag to send a responnse to EPC Gen 2 protocol’s query command. Figure 3 shows thhe calculated read range and threshold power of the printed UHF RFID tag antenna. The tag antenna is operating in the global UHF RFID band. The current flexible tag yields a readd range compared to several commercially available tags of the ssame size.
various inkjet-printing techniques. This will also affect the performance of the UHF RFID tag antenna by further improving the read range of the tag.. VI. CONCLUSSION A method of utilizing inkjet printting technology to fabricate UHF RFID tags on top of ceeramic-polymer composite material is proposed. The tag is prrinted with silver ink using an inkjet printer. The composiite substrate material is developed using high permittivity y BaTiO3 ceramic powder with polydimethysiloxane polymer. This new type of substrate material can be manufactured for a wide range of dielectric d the capability constant values. This investigation demonstrates of using inkjet-printing RFID taags on non-conventional, flexible, and high dielectric constan nt substrate materials while yielding reasonable tag performancee. REFERENCES [1] [2] [3] [4] [5] [6]
Fig. 3. Threshold power and calculated read rangge of the tag antenna using (2).
The following figures show the microscopiic images of the printed tag antenna on top of a ceramic-pollymer composite substrate. Figure 4(a) shows the uniform innk surface of the edges with 5x magnification, whereas Fig. 4(bb) shows the 20x magnified image of the printed tag’s silver ink surface. The mooth and well microscopic images show a relatively sm connected conducting surface of the printed siilver ink tag.
[7] [8] [9] [10] [11] [12]
Silver ink
[13] Substrate [14]
(a) ((b) Fig. 4. Microscopic images with (a) 5x, and (b) 20x magnification of inkjet-printed UHF RFID tag antenna’s surface w with silver ink.
[15]
[16]
D. M. Dobkin, The RF in RFID: passive p UHF RFID in Practice, Elsevier, Amsterdam, 2007. G. Marrocco, and F. Amato, "Self-sen nsing passive RFID: From theory to tag design and experimentation," European E Microwave Conference, EuMC 2009. pp.001-004, Sept. 29 - Occt. 1, 2009. A. Sazonov, D. Striakhilev, C.-H. Leee, A. Nathan, "Low- temperature Materials and Thin Film Transistors for Flexible Electronics," Proc. IEEE, vol.93, no.8, pp.1420-1428, Aug g. 2005. T. H. Sterns, Flexible Printed Circuitryy, McGraw-Hill, New York, 1996. S. R. Forrest, “The path to ubiquitouss and low-cost organic electronic appliances on plastic,” Nature, vol. 428 8, pp. 911–918, April 2004. K. Jain, M. Klosner, M. Zemel, and a S. Raghunandan, “Flexible Electronics and Displays: High-reso olution, Roll-to-Roll, Projection Lithography and Photoablation Proccessing Technologies for HighThroughput Production,” Proc. IEEE E, vol. 93, pp. 1500–1510, Aug. 2005. FUJIFILM Dimatic,Inc.,http://www.dim matix.com A. J. Moulson and J. M. Herbeert, Electroceramics: Materials, Properties, Applications, John Wiley & Sons Ltd, Sept. 2003. J. E. Mark, “Polymer Data Handb book,” New York, NY: Oxford University Press, 1999. L. Guo, H. Luo, J. Gao, L. Guo, J. Yang, Y “Microwave Hydrothermal Synthesis of Barium Titanate Powderss,” Materials Letters, vol. 60, pp. 3011-3014, Oct., 2006. H. Saito, H. Chazono, H. Kishi and d N. Yamaoka, “X7R Multilayer Ceramic Capacitors with Nickel Electrode,” Japanese Journal of Applied Physics, vol. 30, pp.2307-2310 0, 1991. S. Chatterjee and H. S. Maiti, “A Novel Method of Doping PTC Thermistor Sensor Elements during Sintering through Diffusion by Vapour Phase,” Materials Chemistry and a Physics, vol. 67, pp. 294-297, 2001. J. Kuncova-Kallio, P. J. Kallio, "PDMS S and its Suitability for Analytical Microfluidic Devices," Engineering in n Medicine and Biology Society, 28th Annual International Conference of the IEEE, pp.2486-2489, Aug. 30-Sept. 3 2006. Dow Corning Corporation, Sylgard® 184, material properties [Online]. Available: http //www.dowcorning.com m S. Koulouridis, G. Kiziltas, Y. Zhou u, D. J. Hansford, J. L. Volakis, "Polymer–Ceramic Composites for f Microwave Applications: Fabrication and Performance Assessm ment," IEEE Trans. on Microwave Theory and Techniques, vol.54, no.12, pp.4202-4208, Dec. 2006. Voyantic, RFID measurements solution ns, http://www.voyantic.com.
The surface of the UHF RFID tag antenna printed on top of a ceramic-polymer composite substrate lookss well connected. The surface can be made smoother in the futuure, by exploring
978-1-4673-1088-8/12/$31.00 ©2012 IEEE
Rauma Research Unit, Department of Electronics, Tampere University of Technology, Tampere, Finland Micro and Nano Systems Research Group, Department of Automation Science and Engineering, Tampere University of Technology, Tampere, Finland 3 Electrical Engineering Department, The University of Mississippi, University, MS 38677, USA.
2
Abstract — The utilization of inkjet-printing technique to develop a printable UHF RFID tag antenna on flexible ceramicpolymer composite material is demonstrated. The substrate material is fabricated using high permittivity Barium Titanate (BaTiO3) ceramic powder mixed with polydimethylsiloxane (PDMS) polymer. A UHF RFID tag antenna is inkjet-printed using silver nano-particle to exploit the potential advantages of high dielectric flexible composite material when used as a tag substrate. Our preliminary results yielded a small flexible UHF RFID tag antenna with read range comparable to commercially available tag antennas. Index Terms — Flexible Ceramics, Inkjet-printed Tag, RFID Technologies,
I. INTRODUCTION There has been a rapid progress in the field of wireless communications and identification in recent years. Effective and reliable tracking of various objects wirelessly, using radio frequency identification (RFID) technology, is gaining much attention. An RFID system is composed of two main components, the reader and the tag. A passive RFID tag is composed of an IC chip and an antenna. The IC of the tag antenna contains its own unique identification code (ID) [1]. This identification code is sent back to the reader when the tag is interrogated or energized through backscattered modulation of the incident continuous wave [2]. The UHF RFID tag antenna’s input impedance and reflectivity rely on the physical properties of the substrate or the material it is attached to and on the antenna geometry. The size of the tag antenna is greatly dependent on the permittivity of the substrate. Several types of substrates have been used and developed for electronic devices. Similarly, flexible substrates have also gained much importance in recent years [3], [4]. One of the most commonly used plastic substrates is polyester, PEEK (Polyaryletheretherketone) and polymides [5], [6]. There has been a growing interest in the development of flexible antennas. To achieve this, a more desirable approach is to use flexible substrate materials that are less vulnerable to heat, water and other damaging effects. In this paper, a high permittivity polymer-ceramic composite material is developed, for its possible use as a UHF RFID tag antenna substrate. Using substrates with high permittivity values helps in achieving smaller antenna designs.
A UHF RFID tag antenna is printed on top of the substrate using silver ink, with the help of an inkjet printer. The composite substrate is developed using a high permittivity ceramic powder with a polymer known as Polydimethylsiloxane (PDMS). This helps in achieving a soft, flexible, hydrophobic, low loss and heat resistant substrate material. The dielectric and physical properties of the composite material depend on the fabrication process, ratio and type of ceramic powder used. The permittivity values of the material can be changed by changing the amount of the ceramic powder in the composite. This provides the flexibility to achieve the desired high permittivity value of the substrate, and thus a small size tag antenna. Inkjet-printing using DMP-2800 inkjet-printer from FujiFilm Dimatix is chosen as the fabrication method as it allows rapid prototyping and non-contact fabrication of flexible conducting traces [7]. It can also be seen as a prominent fabrication method in the future of UHF RFID tags. Thus, this work also aims to demonstrate capability of inkjetprinting RFID tags on non-conventional substrate materials. II. CHARACTERISTIC OF THE COMPOSITE SUBSTRATE The ceramic-polymer composite substrate is developed by mixing Barium titanate (BaTiO3) ceramic powder with a polymer known as Polydimethylsiloxane. BaTiO3 is a ferroelectric ceramic, usually available in powder form, with piezoelectric properties [8]. It usually has high permittivity values [9]. However, the permittivity depends on several factors, such as grain size, shape and size of the crystals, impurities, and on other processing techniques [10]. These types of ferroelectric ceramics can be used in several electronic applications, such as multilayer capacitors [11], positive temperature coefficient (PTC) thermistors, transducers and tunable phase shifters [12]. Polydimethylsiloxane (PDMS) is a most widely used type of a silicon based organic polymer, belonging to a group of siloxanes. It is available in fluid, elastomer and resin form [9]. PDMS material has high thermal stability, low surface tension, and bulk viscosity. It is transparent in nature, durable at high temperatures, and hydrophobic. In elastomer form PDMS is suitable for flexible substrates. They are fabricated using
978-1-4673-1088-8/12/$31.00 ©2012 IEEE
viscous liquid and a liquid cross-linking agentt. The stiffness of the substrate depend on the amount of crooss-linking agent used, curing time and temperature. Theirr most common applications include rubber molds, surrfactants, water repellents, personal care and cosmeetics, dielectric encapsulation, contact lenses, medical aand microfluidic devices [13]. The substrate developed here is low loss, sooft and flexible in nature, resistant to water, heat, breaking andd other damaging effects. Desired permittivity values of the substrate can be achieved by changing the ratio of ceramic iin the composite substrate. This type of a substrate enables too achieve smaller tag antenna designs. (a) (b) Fig. 1. UHF RFID tag antenna (a) ( Geometrical parameters, (b) Printed on flexible ceramic-polymerr substrate.
III. SUBSTRATE FABRICATION PROCEEDURE The fabrication process of the ceramic-polyymer substrate is described in a stepwise approach. The PDMS used is Sylgard184, supplied with a two component kit coontaining a ‘base pre-polymer’ and a curing agent (crosss-linking agent) manufactured by Dow Corning [14]. The BaT TiO3 was supplied by Sachtleben Ltd. Following steps were useed to develop the composite substrate. A similar approach has aalso been studied in [15]. 1) The pre-polymer is mixed with the ccuring agent in a mass ratio of 10 (pre-polymer): 1(curinng agent). 2) Degassing is performed to remove th the excessive air bubbles formed during the mixing for 115-20min. 3) Then the PDMS is vigorously mixeed with BaTiO3 powder in a volume based ratio using eeq. (1).
%
⁄ ⁄
⁄
100%
(1)
In the above equation ‘ ’ and ‘ ’refer to the mass and density of the ceramic (BaTiO3), respectivelyy. Whereas, ‘ ’ and ‘ ’ are the mass and density of the polym mer (PDMS). 4) The smooth paste is left for degassing ffor 5-6 hours and kept under vacuum pressure for arouund 30 hours to remove most of the air bubbles from thhe mixture. IV. ANTENNA DESIGN A small symmetric dipole tag antenna design is printed on top of the composite substrate. The compoosite substrate is 1.5mm thick and has a dielectric constant cloose to 7. The tag antenna is designed using HFSS v.12. Alien H Higgs 3 IC with 18dBm sensitivity is attached between the tw wo feeding pads with dimensions ‘a’ and ‘b’. Figure 1 (a) shows the geometrical parameters of the UHF RFID ttag antenna. The dimensions of the tag antenna are listed in Table 1. The IC was connected directly to the printed tagg antenna using conductive epoxy glue.
TABLE I DIMENSIONS OF THE GEOMETRICAL L PARAMETERS OF THE TAG Line a b c d e f
Length (mm) 3.25 2.5 0.75 3.55 3.75 1
Width (mm) 2 2 -
Line g h k m n o
Length (mm) 14.5 4.15 6.75 7.5 16.6 26.5
Width (mm) 0.5 -
V. RESULT TS The following results demonstrate the possibility of developing inkjet-printed UHF RFIID tag on top of a ceramicpolymer composite substrate. Figu ure 1 (b) shows a recently designed a small UHF RFID tag which w is inkjet-printed with 4 layers of Harima NPS-JL silver nanoparticle ink having a 6 µ••cm specific resistance. particle size equal to 7 nm and 4-6 The optimal printing resolution wass found to be 847 dpi. First the tag is printed with 2 layers of silver s ink and sintered; this is followed by re-printing of 2 addiitional layers and sintering. The printed tag is sintered for 40 minutes m at a temperature of 170 Celsius. The performance of o the tag antenna can be further enhanced in the future by an nalyzing and improving the current technique. The RFID tag antenna is testeed for its read range and minimum threshold power required d to turn on the IC, in an anechoic chamber by Voyantic corrporations [16]. A linearly polarized reader antenna inside thee chamber is connected to the Tagformance measurement device to measure the performance of the RFID tag anten nna. The read range of the tag is calculated using the meeasured results from the Tagformance, using the following equation. e .
.
978-1-4673-1088-8/12/$31.00 ©2012 IEEE
(2)
In (2), ‘dtag’ represents the read range of the tag antenna. ‘Lfwd’ is the measured path loss from the geenerator’s output port to the input port of a hypothetical issotropic antenna placed at the tag’s location. The forward path loss is computed from the measured calibration data obtaained from the Tagformance measurement device. The Euuropean effective radiated power ‘PERP’ is considered to bee equal to 2W (33dBm). The parameter ‘Pth’ representss the measured threshold power in the forward direction, from m the transmitter to the tag antenna. The threshold power iis the minimum continuous wave power from the transmitter,, required to turn on the IC and enable the tag to send a responnse to EPC Gen 2 protocol’s query command. Figure 3 shows thhe calculated read range and threshold power of the printed UHF RFID tag antenna. The tag antenna is operating in the global UHF RFID band. The current flexible tag yields a readd range compared to several commercially available tags of the ssame size.
various inkjet-printing techniques. This will also affect the performance of the UHF RFID tag antenna by further improving the read range of the tag.. VI. CONCLUSSION A method of utilizing inkjet printting technology to fabricate UHF RFID tags on top of ceeramic-polymer composite material is proposed. The tag is prrinted with silver ink using an inkjet printer. The composiite substrate material is developed using high permittivity y BaTiO3 ceramic powder with polydimethysiloxane polymer. This new type of substrate material can be manufactured for a wide range of dielectric d the capability constant values. This investigation demonstrates of using inkjet-printing RFID taags on non-conventional, flexible, and high dielectric constan nt substrate materials while yielding reasonable tag performancee. REFERENCES [1] [2] [3] [4] [5] [6]
Fig. 3. Threshold power and calculated read rangge of the tag antenna using (2).
The following figures show the microscopiic images of the printed tag antenna on top of a ceramic-pollymer composite substrate. Figure 4(a) shows the uniform innk surface of the edges with 5x magnification, whereas Fig. 4(bb) shows the 20x magnified image of the printed tag’s silver ink surface. The mooth and well microscopic images show a relatively sm connected conducting surface of the printed siilver ink tag.
[7] [8] [9] [10] [11] [12]
Silver ink
[13] Substrate [14]
(a) ((b) Fig. 4. Microscopic images with (a) 5x, and (b) 20x magnification of inkjet-printed UHF RFID tag antenna’s surface w with silver ink.
[15]
[16]
D. M. Dobkin, The RF in RFID: passive p UHF RFID in Practice, Elsevier, Amsterdam, 2007. G. Marrocco, and F. Amato, "Self-sen nsing passive RFID: From theory to tag design and experimentation," European E Microwave Conference, EuMC 2009. pp.001-004, Sept. 29 - Occt. 1, 2009. A. Sazonov, D. Striakhilev, C.-H. Leee, A. Nathan, "Low- temperature Materials and Thin Film Transistors for Flexible Electronics," Proc. IEEE, vol.93, no.8, pp.1420-1428, Aug g. 2005. T. H. Sterns, Flexible Printed Circuitryy, McGraw-Hill, New York, 1996. S. R. Forrest, “The path to ubiquitouss and low-cost organic electronic appliances on plastic,” Nature, vol. 428 8, pp. 911–918, April 2004. K. Jain, M. Klosner, M. Zemel, and a S. Raghunandan, “Flexible Electronics and Displays: High-reso olution, Roll-to-Roll, Projection Lithography and Photoablation Proccessing Technologies for HighThroughput Production,” Proc. IEEE E, vol. 93, pp. 1500–1510, Aug. 2005. FUJIFILM Dimatic,Inc.,http://www.dim matix.com A. J. Moulson and J. M. Herbeert, Electroceramics: Materials, Properties, Applications, John Wiley & Sons Ltd, Sept. 2003. J. E. Mark, “Polymer Data Handb book,” New York, NY: Oxford University Press, 1999. L. Guo, H. Luo, J. Gao, L. Guo, J. Yang, Y “Microwave Hydrothermal Synthesis of Barium Titanate Powderss,” Materials Letters, vol. 60, pp. 3011-3014, Oct., 2006. H. Saito, H. Chazono, H. Kishi and d N. Yamaoka, “X7R Multilayer Ceramic Capacitors with Nickel Electrode,” Japanese Journal of Applied Physics, vol. 30, pp.2307-2310 0, 1991. S. Chatterjee and H. S. Maiti, “A Novel Method of Doping PTC Thermistor Sensor Elements during Sintering through Diffusion by Vapour Phase,” Materials Chemistry and a Physics, vol. 67, pp. 294-297, 2001. J. Kuncova-Kallio, P. J. Kallio, "PDMS S and its Suitability for Analytical Microfluidic Devices," Engineering in n Medicine and Biology Society, 28th Annual International Conference of the IEEE, pp.2486-2489, Aug. 30-Sept. 3 2006. Dow Corning Corporation, Sylgard® 184, material properties [Online]. Available: http //www.dowcorning.com m S. Koulouridis, G. Kiziltas, Y. Zhou u, D. J. Hansford, J. L. Volakis, "Polymer–Ceramic Composites for f Microwave Applications: Fabrication and Performance Assessm ment," IEEE Trans. on Microwave Theory and Techniques, vol.54, no.12, pp.4202-4208, Dec. 2006. Voyantic, RFID measurements solution ns, http://www.voyantic.com.
The surface of the UHF RFID tag antenna printed on top of a ceramic-polymer composite substrate lookss well connected. The surface can be made smoother in the futuure, by exploring
978-1-4673-1088-8/12/$31.00 ©2012 IEEE
