Inkjet-Printed Electromagnet-Based Touchpad Using Spiral Resonators

In this paper, an inkjet-printed electromagnet-based touchpad employing spiral resonators is proposed. The proposed touchpad is fabricated by a direct patterning method using an inkjet printer with a conductive silver nanoparticle ink. The conductive patterns are easily printed on a paper substrate and sintered for achieving good conductivity. The proposed touchpad is composed of two spiral resonators that resonate at 0.94 GHz (f1) and 1.83 GHz (f2), respectively. When the first resonator is touched, f1 decreases from 0.94 to 0.81 GHz because of electromagnetic (EM) coupling between the finger and the spiral resonator. Similarly, when the second resonator is touched, f2 decreases from 1.83 to 1.55 GHz. Owing to the EM coupling distance between the spiral resonator and the finger, the frequency changes although the finger does not reach beyond a height of 1.27 mm on the spiral resonator. The performance of the proposed touchpad is validated using simulation and measurement results.

[1]  Heli Jantunen,et al.  Inkjet printing of electrically conductive patterns of carbon nanotubes. , 2006, Small.

[2]  D. Gundlach,et al.  Organic electronics. Low power, high impact. , 2007, Nature materials.

[3]  Soon-Ki Kwon,et al.  Flexible High‐Performance All‐Inkjet‐Printed Inverters: Organo‐Compatible and Stable Interface Engineering , 2013, Advanced materials.

[4]  John A Rogers,et al.  Interfacial chemistries for nanoscale transfer printing. , 2002, Journal of the American Chemical Society.

[5]  A. Toscano,et al.  Equivalent-Circuit Models for the Design of Metamaterials Based on Artificial Magnetic Inclusions , 2007, IEEE Transactions on Microwave Theory and Techniques.

[6]  Naomi J. Halas,et al.  Photodetection with Active Optical Antennas , 2011, Science.

[7]  I. Park,et al.  Nanoscale Patterning and Electronics on Flexible Substrate by Direct Nanoimprinting of Metallic Nanoparticles , 2007 .

[8]  Aaron D. Mazzeo,et al.  Paper‐Based, Capacitive Touch Pads , 2012, Advanced materials.

[9]  I. Park,et al.  Direct nanoimprinting of metal nanoparticles for nanoscale electronics fabrication. , 2007, Nano letters.

[10]  A. Toscano,et al.  Design of Spiral and Multiple Split-Ring Resonators for the Realization of Miniaturized Metamaterial Samples , 2007, IEEE Transactions on Antennas and Propagation.

[11]  John A. Rogers,et al.  Omnidirectional Printing of Flexible, Stretchable, and Spanning Silver Microelectrodes , 2009, Science.

[12]  John A. Rogers,et al.  Electrical Contacts to Molecular Layers by Nanotransfer Printing , 2003 .

[13]  W. Jesser,et al.  Thermodynamic theory of size dependence of melting temperature in metals , 1977, Nature.

[14]  W. Kim,et al.  Repeatedly Bendable Paper Touch Pad via Direct Stamping of Silver Nanoink With Pressure-Induced Low-Temperature Annealing , 2013, IEEE Transactions on Nanotechnology.

[15]  Xiao Li,et al.  Paper-based piezoelectric touch pads with hydrothermally grown zinc oxide nanowires. , 2014, ACS applied materials & interfaces.

[16]  Jaehoon Choi,et al.  Manufacturing of a Korean Hand Phantom with Human Electrical Properties at 835 MHz and 1,800 MHz Bands , 2013 .

[17]  S. Ko,et al.  Microelectrode fabrication by laser direct curing of tiny nanoparticle self-generated from organometallic ink. , 2011, Optics express.

[18]  R. Österbacka,et al.  Paper Electronics , 2011, Advanced materials.

[19]  Jooho Moon,et al.  Direct nanoprinting by liquid-bridge-mediated nanotransfer moulding. , 2010, Nature nanotechnology.

[20]  Ruo-Zhou Li,et al.  Direct writing on paper of foldable capacitive touch pads with silver nanowire inks. , 2014, ACS applied materials & interfaces.

[21]  J. Lewis,et al.  Pen‐on‐Paper Flexible Electronics , 2011, Advanced materials.