# Adaptive Impedance Matching Network for Contactless Power and Data Transfer in E-Textiles

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Methods

#### 2.1. Link Design

#### 2.1.1. Link Characterization

#### 2.1.2. Link Compensation

#### 2.1.3. Quality Factor

#### 2.1.4. Non-Idealities

#### 2.1.5. Practical Implementation

#### 2.2. Supporting Electronics

#### 2.2.1. Carrier Generator

#### 2.2.2. Modulation and Demodulation

#### 2.2.3. Coupling Detection

#### 2.2.4. Practical Implementation

## 3. Results and Discussion

#### 3.1. Maximum Data Speeds

#### 3.2. Power Transfer Capabilities

#### 3.3. Coupling Correction

#### 3.4. Future Work

## 4. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

- Fernández-Caramés, T.M.; Fraga-Lamas, P. Towards The Internet of Smart Clothing: A Review on IoT Wearables and Garments for Creating Intelligent Connected E-Textiles. Electronics
**2018**, 7, 405. [Google Scholar] [CrossRef][Green Version] - Smart Clothing Market by Textile Type, Product Type (Upper Wear, Lower Wear, Innerwear, and Others), End-User Industry (Military & Defense, Sports & Fitness, Fashion & Entertainment, Healthcare), and Geography—Global Forecast to 2024. Technical report, MarketsandMarkets, 2019. Available online: https://www.marketsandmarkets.com/Market-Reports/smart-clothing-market-56415040.html (accessed on 20 June 2021).
- Caya, M.V.C.; Cruz, F.R.G.; Linsangan, N.B.; Catipon, M.A.M.D.; Monje, P.I.T.; Tan, H.K.R.; Chung, W.Y. Basal body temperature measurement using e-textile. In Proceedings of the 2017 IEEE ninth International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment and Management (HNICEM), Manila, Philippines, 1–3 December 2017; pp. 1–4. [Google Scholar]
- López, G.; Custodio, V.; Moreno, J.I. LOBIN: E-textile and wireless-sensor-network-based platform for healthcare monitoring in future hospital environments. IEEE Trans. Inf. Technol. Biomed.
**2010**, 14, 1446–1458. [Google Scholar] [CrossRef] [PubMed] - Caya, M.V.C.; Casaje, J.S.; Catapang, G.B.; Dandan, R.A.V.; Linsangan, N.B. Warning system for firefighters using e-textile. In Proceedings of the 2018 Third International Conference on Computer and Communication Systems (ICCCS), Nagoya, Japan, 27–30 April 2018; pp. 362–366. [Google Scholar]
- Qi, W.; Aliverti, A. A multimodal wearable system for continuous and real-time breathing pattern monitoring during daily activity. IEEE J. Biomed. Health Inform.
**2019**, 24, 2199–2207. [Google Scholar] [CrossRef] - Mieloszyk, R.; Twede, H.; Lester, J.; Wander, J.; Basu, S.; Cohn, G.; Smith, G.; Morris, D.; Gupta, S.; Tan, D.; et al. A Comparison of Wearable Tonometry, Photoplethysmography, and Electrocardiography for Cuffless Measurement of Blood Pressure in an Ambulatory Setting. IEEE J. Biomed. Health Inform.
**2022**, 26, 2864–2875. [Google Scholar] [CrossRef] - Zou, P.; Wang, Y.; Cai, H.; Peng, T.; Pan, T.; Li, R.; Fan, Y. Wearable Iontronic FMG for Classification of Muscular Locomotion. IEEE J. Biomed. Health Inform.
**2022**, 26, 2854–2863. [Google Scholar] [CrossRef] [PubMed] - Bastiaansen, B.J.; Wilmes, E.; Brink, M.S.; de Ruiter, C.J.; Savelsbergh, G.J.; Steijlen, A.; Jansen, K.M.; van der Helm, F.C.; Goedhart, E.A.; van der Laan, D.; et al. An inertial measurement unit based method to estimate hip and knee joint kinematics in team sport athletes on the field. JoVE (J. Vis. Exp.)
**2020**, 159, e60857. [Google Scholar] - Dias, T. (Ed.) Wearable Sensors Fundamentals, Implementation and Applications; Elsevier Inc.: Amsterdam, The Netherlands, 2015. [Google Scholar]
- Gonzalez, M.; Axisa, F.; Bulcke, M.V.; Brosteaux, D.; Vandevelde, B.; Vanfleteren, J. Design of metal interconnects for stretchable electronic circuits. Microelectron. Reliab.
**2008**, 48, 825–832. [Google Scholar] [CrossRef] - Dils, C.; Werft, L.; Walter, H.; Zwanzig, M.; Krshiwoblozki, M.v.; Schneider-Ramelow, M. Investigation of the mechanical and electrical properties of elastic textile/polymer composites for stretchable electronics at quasi-static or cyclic mechanical loads. Materials
**2019**, 12, 3599. [Google Scholar] [CrossRef][Green Version] - Simegnaw, A.A.; Malengier, B.; Rotich, G.; Tadesse, M.G.; Van Langenhove, L. Review on the Integration of Microelectronics for E-Textile. Materials
**2021**, 14, 5113. [Google Scholar] [CrossRef] - Stanley, J.; Hunt, J.A.; Kunovski, P.; Wei, Y. A review of connectors and joining technologies for electronic textiles. Eng. Rep.
**2021**, 4, e12491. [Google Scholar] [CrossRef] - Koshi, T.; Nomura, K.i.; Yoshida, M. Electronic component mounting for durable e-textiles: Direct soldering of components onto textile-based deeply permeated conductive patterns. Micromachines
**2020**, 11, 209. [Google Scholar] [CrossRef] [PubMed][Green Version] - Micus, S.; Haupt, M.; Gresser, G.T. Automatic Joining of Electrical Components to Smart Textiles by Ultrasonic Soldering. Sensors
**2021**, 21, 545. [Google Scholar] [CrossRef] [PubMed] - Micus, S.; Kirsten, I.; Haupt, M.; Gresser, G.T. Analysis of Hot Bar Soldering, Insulation Displacement Connections (IDC), and Anisotropic Conductive Adhesives (ACA), for the Automated Production of Smart Textiles. Sensors
**2020**, 20, 5. [Google Scholar] [CrossRef] [PubMed][Green Version] - Linz, T.; Kallmayer, C.; Aschenbrenner, R.; Reichl, H. Embroidering electrical interconnects with conductive yarn for the integration of flexible electronic modules into fabric. In Proceedings of the Ninth IEEE International Symposium on Wearable Computers (ISWC’05), Osaka, Japan, 18–21 October 2005; pp. 86–89. [Google Scholar]
- Locher, I.; Sefar, A. Joining technologies for smart textiles. In Multidisciplinary Know-How for Smart-Textiles Developers; Elsevier: Amsterdam, The Netherlands, 2013; pp. 285–305. [Google Scholar]
- Linz, T.; Vieroth, R.; Dils, C.; Koch, M.; Braun, T.; Becker, K.F.; Kallmayer, C.; Hong, S.M. Embroidered interconnections and encapsulation for electronics in textiles for wearable electronics applications. In Advances in Science and Technology; Trans Tech Publications Ltd.: Stafa-Zurich, Switzerland, 2008; Volume 60, pp. 85–94. [Google Scholar]
- Köhler, A.R. Challenges for eco-design of emerging technologies: The case of electronic textiles. Mater. Des.
**2013**, 51, 51–60. [Google Scholar] [CrossRef] - Yao, Y.; Sun, P.; Liu, X.; Wang, Y.; Xu, D. Simultaneous wireless power and data transfer: A comprehensive review. IEEE Trans. Power Electron.
**2021**, 37, 3650–3667. [Google Scholar] [CrossRef] - Qian, Z.; Yan, R.; Wu, J.; He, X. Full-duplex high-speed simultaneous communication technology for wireless EV charging. IEEE Trans. Power Electron.
**2019**, 34, 9369–9373. [Google Scholar] [CrossRef] - Karimi, M.J.; Schmid, A.; Dehollain, C. Wireless power and data transmission for implanted devices via inductive links: A systematic review. IEEE Sens. J.
**2021**, 21, 7145–7161. [Google Scholar] [CrossRef] - Wen, S.; Heidari, H.; Vilouras, A.; Dahiya, R. A wearable fabric-based RFID skin temperature monitoring patch. In Proceedings of the 2016 IEEE SENSORS, Orlando, FL, USA, 30 October–3 November 2016; pp. 1–3. [Google Scholar]
- Jiang, Y.; Xu, L.; Pan, K.; Leng, T.; Li, Y.; Danoon, L.; Hu, Z. e-Textile embroidered wearable near-field communication RFID antennas. IET Microwaves Antennas Propag.
**2019**, 13, 99–104. [Google Scholar] [CrossRef][Green Version] - Del-Rio-Ruiz, R.; Lopez-Garde, J.M.; Macon, J.L.; Rogier, H. Design and performance analysis of a purely textile spiral antenna for on-body NFC applications. In Proceedings of the 2017 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP), Pavia, Italy, 20–22 September 2017; pp. 1–3. [Google Scholar]
- Niu, S.; Matsuhisa, N.; Beker, L.; Li, J.; Wang, S.; Wang, J.; Jiang, Y.; Yan, X.; Yun, Y.; Burnett, W.; et al. A wireless body area sensor network based on stretchable passive tags. Nat. Electron.
**2019**, 2, 361–368. [Google Scholar] [CrossRef] - Lin, R.; Kim, H.J.; Achavananthadith, S.; Kurt, S.A.; Tan, S.C.; Yao, H.; Tee, B.C.; Lee, J.K.; Ho, J.S. Wireless battery-free body sensor networks using near-field-enabled clothing. Nat. Commun.
**2020**, 11, 444. [Google Scholar] [CrossRef][Green Version] - Garnier, B.; Mariage, P.; Rault, F.; Cochrane, C.; Koncar, V. Electronic-components less fully textile multiple resonant combiners for body-centric near field communication. Sci. Rep.
**2021**, 11, 2159. [Google Scholar] [CrossRef] [PubMed] - Garnier, B.; Mariage, P.; Rault, F.; Cochrane, C.; Konçar, V. Textile NFC antenna for power and data transmission across clothes. Smart Mater. Struct.
**2020**, 29, 085017. [Google Scholar] [CrossRef] - Ye, H.; Lee, C.J.; Wu, T.Y.; Yang, X.D.; Chen, B.Y.; Liang, R.H. Body-Centric NFC: Body-Centric Interaction with NFC Devices through Near-Field Enabled Clothing. In Proceedings of the Designing Interactive Systems Conference, Virtual Event, 13–17 June 2022; pp. 1626–1639. [Google Scholar]
- Lindeman, W. Contactless Inductive Power and Data Transfer: For use in E-Textiles. Master’s Thesis, Delft University of Technology, Delft, The Netherlands, 2022. [Google Scholar]
- Stielau, O.H.; Covic, G.A. Design of loosely coupled inductive power transfer systems. In Proceedings of the PowerCon 2000, 2000 International Conference on Power System Technology, Proceedings (Cat. No. 00EX409), Perth, WA, Australia, 4–7 December 2000; Volume 1, pp. 85–90. [Google Scholar]
- Wang, C.S.; Stielau, O.H.; Covic, G.A. Design considerations for a contactless electric vehicle battery charger. IEEE Trans. Ind. Electron.
**2005**, 52, 1308–1314. [Google Scholar] [CrossRef] - Mude, K.; Aditya, K. Comprehensive review and analysis of two-element resonant compensation topologies for wireless inductive power transfer systems. Chin. J. Electr. Eng.
**2019**, 5, 14–31. [Google Scholar] [CrossRef] - Joseph, P.K.; Elangovan, D. A review on renewable energy powered wireless power transmission techniques for light electric vehicle charging applications. J. Energy Storage
**2018**, 16, 145–155. [Google Scholar] [CrossRef] - Prasanth, V. Wireless Power Transfer for E-Mobility. Master’s Thesis, Electrical Sustainable Energy Deptartment, Delft University of Techology, Delft, The Netherlands, 2012. [Google Scholar]
- Green, E.I. The story of Q. Am. Sci.
**1955**, 43, 584–594. [Google Scholar] - Corti, F.; Grasso, F.; Reatti, A.; Ayachit, A.; Saini, D.K.; Kazimierczuk, M.K. Design of class-E ZVS inverter with loosely-coupled transformer at fixed coupling coefficient. In Proceedings of the IECON 2016—42nd Annual Conference of the IEEE Industrial Electronics Society, Florence, Italy, 23–26 October 2016; pp. 5627–5632. [Google Scholar]
- Chen, W.; Chinga, R.; Yoshida, S.; Lin, J.; Chen, C.; Lo, W. A 25.6 W 13.56 MHz wireless power transfer system with a 94% efficiency GaN class-E power amplifier. In Proceedings of the 2012 IEEE/MTT-S International Microwave Symposium Digest, Montreal, QC, Canada, 17–22 June 2012; pp. 1–3. [Google Scholar]
- Liu, S.; Liu, M.; Fu, M.; Ma, C.; Zhu, X. A high-efficiency Class-E power amplifier with wide-range load in WPT systems. In Proceedings of the 2015 IEEE Wireless Power Transfer Conference (WPTC), Boulder, CO, USA, 13–15 May 2015; pp. 1–3. [Google Scholar]
- Low, Z.N.; Chinga, R.A.; Tseng, R.; Lin, J. Design and test of a high-power high-efficiency loosely coupled planar wireless power transfer system. IEEE Trans. Ind. Electron.
**2008**, 56, 1801–1812. [Google Scholar] - Pinuela, M.; Yates, D.C.; Lucyszyn, S.; Mitcheson, P.D. Maximizing DC-to-load efficiency for inductive power transfer. IEEE Trans. Power Electron.
**2012**, 28, 2437–2447. [Google Scholar] [CrossRef][Green Version] - Fu, M.; Yin, H.; Liu, M.; Ma, C. Loading and power control for a high-efficiency class E PA-driven megahertz WPT system. IEEE Trans. Ind. Electron.
**2016**, 63, 6867–6876. [Google Scholar] [CrossRef] - Sokal, N.O.; Sokal, A.D. Class E—A new class of high-efficiency tuned single-ended switching power amplifiers. IEEE J. Solid-State Circuits
**1975**, 10, 168–176. [Google Scholar] [CrossRef]

**Figure 6.**System Q for various loads and coupling factors (k). $L=500$ nH and $\omega =2\pi \xb713.56$ MHz.

**Figure 7.**A grid of Nyquist plots showing how the real part (x-axis) and imaginary part (y-axis) of the input impedance of the link change as one of the link parameters (${k}_{1}$, ${k}_{2}$, and ${L}_{11}$–${L}_{22}$) is varied from −10% to +10% of its nominal value. Each column of plots corresponds to a different parameter, whereas the rows indicate different nominal values for L. A longer line indicates a greater sensitivity to the selected parameter. The tick-marks on the axis are placed at a 50 $\Omega $ distance from the origin. Each simulation was performed at a frequency of $13.56$ MHz with a 50 $\Omega $ load and a nominal coupling factor of 0.7.

**Figure 8.**Nyquist plot of the link input impedance as the length of the transmission line between ${L}_{12}$ and ${L}_{21}$ increases from 0 to 0.5 m. The various traces correspond to different characteristic transmission line impedances. The transmission line used in the simulation has a wave propagation speed of $0.6c$ and is terminated in a 50 $\Omega $ load.

**Figure 10.**(

**a**) Simulated time-domain waveforms of the output signal of the modified class-E amplifier. (

**b**) Spectral use of the output signal.

**Figure 12.**Image of the prototype. In this picture, coil pair #2 is placed in a holder with a fixed spacing, and coil pair #1 is loose.

**Figure 13.**Signal waveforms during square wave communication. (

**a**) Master-to-slave communication at 120 kHz. The top signal is the modulated carrier sent by the master. The bottom signal is the demodulated signal output by the slave. The vertical scale is 5 V/div. (

**b**) Slave to master communication at 180 kHz. The top signal is the data stream presented to the input of the slave. The bottom signal is the demodulated signal output by the master. The vertical scale is 2 V/div.

**Figure 15.**Measured DC efficiency and phase detector output for various DC loads at a coil distance of 1.5 mm.

**Table 1.**Common values for primary compensation capacitors and their resulting transmission matrices at resonance ($\omega ={\omega}_{0}$).

Topology | ${\mathit{C}}_{\mathit{p}}$ | ${\mathit{C}}_{\mathit{s}}$ | $\left[\begin{array}{c}\mathit{T}\end{array}\right]$ |
---|---|---|---|

SS | $\frac{1}{{\omega}_{0}^{2}\widehat{L}}$ | $\frac{1}{{\omega}_{0}^{2}\widehat{L}}$ | $\left[\begin{array}{cc}0& \frac{{\omega}_{0}\widehat{k}\widehat{L}}{j}\\ \frac{j}{{\omega}_{0}\widehat{k}\widehat{L}}& 0\end{array}\right]$ |

SP | $\frac{\widehat{1}}{{\omega}_{0}^{2}\widehat{L}(1-{\widehat{k}}^{2})}$ | $\frac{1}{{\omega}_{0}^{2}\widehat{L}}$ | $\left[\begin{array}{cc}\widehat{k}& 0\\ 0& \frac{1}{\widehat{k}}\end{array}\right]$ |

PP | $\frac{(1-{\widehat{k}}^{2})\widehat{L}}{{\omega}_{0}^{2}{\widehat{L}}^{2}{(1-{\widehat{k}}^{2})}^{2}+{\widehat{k}}^{4}{Z}_{l}^{2}}$ | $\frac{1}{{\omega}_{0}^{2}\widehat{L}}$ | $\left[\begin{array}{cc}\widehat{k}& \frac{\widehat{L}{\omega}_{0}(1-{\widehat{k}}^{2})}{\widehat{k}}\\ \frac{j{\omega}_{0}\widehat{L}\widehat{k}(1-{\widehat{k}}^{2})}{{\omega}_{0}^{2}{\widehat{L}}^{2}{(1-{\widehat{k}}^{2})}^{2}+{Z}_{l}{\widehat{k}}^{4}}& \frac{{Z}_{l}{\widehat{k}}^{4}}{{\omega}_{0}^{2}{\widehat{L}}^{2}{(1-{\widehat{k}}^{2})}^{2}+{Z}_{l}{\widehat{k}}^{4}}\end{array}\right]$ |

PS | $\frac{{Z}_{l}^{2}}{{\omega}_{0}^{2}\widehat{L}{Z}_{l}^{2}+{\omega}_{0}^{3}\widehat{L}{\widehat{k}}^{4}}$ | $\frac{1}{{\omega}_{0}^{2}\widehat{L}}$ | $\left[\begin{array}{cc}\frac{1}{\widehat{k}}& \frac{{\omega}_{0}\widehat{k}\widehat{L}}{j}\\ \frac{\widehat{L}{\widehat{k}}^{3}{\omega}_{0}}{j{\widehat{L}}^{2}{\widehat{k}}^{4}{\omega}_{0}^{2}+j{Z}_{l}}& \frac{\widehat{k}{Z}_{l}}{{\widehat{L}}^{2}{\widehat{k}}^{4}{\omega}_{0}^{2}+{Z}_{l}}\end{array}\right]$ |

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**MDPI and ACS Style**

Lindeman, P.; Steijlen, A.; Bastemeijer, J.; Bossche, A.
Adaptive Impedance Matching Network for Contactless Power and Data Transfer in E-Textiles. *Sensors* **2023**, *23*, 2943.
https://doi.org/10.3390/s23062943

**AMA Style**

Lindeman P, Steijlen A, Bastemeijer J, Bossche A.
Adaptive Impedance Matching Network for Contactless Power and Data Transfer in E-Textiles. *Sensors*. 2023; 23(6):2943.
https://doi.org/10.3390/s23062943

**Chicago/Turabian Style**

Lindeman, Pim, Annemarijn Steijlen, Jeroen Bastemeijer, and Andre Bossche.
2023. "Adaptive Impedance Matching Network for Contactless Power and Data Transfer in E-Textiles" *Sensors* 23, no. 6: 2943.
https://doi.org/10.3390/s23062943